diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 08057e0..c6e0539 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -24,3 +24,5 @@ jobs:
       - run: npm run test
 
       - run: npm run build
+
+      - run: npm run check:dist
diff --git a/ARCHITECTURE_ESSENTIALS.md b/ARCHITECTURE_ESSENTIALS.md
index ea649ec..d58953c 100644
--- a/ARCHITECTURE_ESSENTIALS.md
+++ b/ARCHITECTURE_ESSENTIALS.md
@@ -25,6 +25,13 @@ those first if you're new to the org, not just this file.
 ## Where things live
 - `src/services/` — API client calls to `docforum-core`. `api-client.ts` is
   the only place fetch/base-URL/error-envelope details live.
+- `src/mocks/` — MSW mock API for `npm run dev:mock` (issue #95). Handlers
+  mirror the same real/assumed contracts `src/services/` calls, over
+  obviously fake `example.test` fixtures. Loaded only behind the
+  `import.meta.env.DEV && VITE_ENABLE_MOCKS` guard in `main.tsx`, before
+  the first render; production bundles must never contain it — CI enforces
+  this via `npm run check:dist`. When an assumed contract in this file is
+  reconciled, update `src/mocks/` fixtures/handlers in the same PR.
 - `src/features/` — flow-specific logic (booking, referral-accept, order
   fulfillment selection, etc.) — one feature folder per PRD core flow.
 - `src/pages/` — route-level components.
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index e3e2051..5c5d33c 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -20,6 +20,33 @@ to actually do anything: run `docforum-core`'s backend yourself (see its
 `CONTRIBUTING.md`), or point `VITE_API_BASE_URL` at a hosted instance.
 `npm run dev` defaults to `http://localhost:4000`.
 
+### Run with no backend at all: the mock API
+
+`npm run dev:mock` starts the same Vite dev server with an
+[MSW](https://mswjs.io)-backed mock of every endpoint the app calls —
+no `docforum-core` needed:
+
+- **Role switcher** — jump straight into the patient, doctor, facility or
+  admin experience (seeded personas with obviously fake data, all
+  `@example.test` emails). Logging in through the real login screen works
+  too; any email logs you in as the selected role.
+- **Scenarios** — toggle empty datasets and forced 500s to see empty and
+  error states without hand-crafting backend conditions.
+- **Latency** — delay every response (0–3 s) to check loading states.
+- **Reset data** — restore the fixture database after in-session
+  mutations (nothing is persisted; fixtures reset on reload).
+
+Mock handlers live in `src/mocks/` and sit on top of the fixtures in
+`src/mocks/fixtures.ts`. The app still reaches them through the normal
+service layer (`src/services/`), so screens behave exactly as they do
+against the real API. Mock code is excluded from production builds, and
+CI fails if it ever leaks (`npm run check:dist`).
+
+**When you add a service call to a new endpoint**, add a handler and
+fixtures in `src/mocks/` in the same PR, and cover it in
+`src/mocks/handlers.test.ts` — that's what keeps `dev:mock` honest as the
+API grows.
+
 ## 2. Find something to work on
 
 Open issues are scoped, real, and tagged with a complexity/point value
diff --git a/ROADMAP.md b/ROADMAP.md
index e1d6738..71093d5 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -86,6 +86,12 @@ real API" (no refresh-on-reload flow).
   a session exists, same caveat as the facility dashboard already had.
 - [ ] Link transaction hashes/escrows to the Stellar testnet explorer. Tracked as [issue #10](https://github.com/DocForum/docforum-web/issues/10) (Trivial, 100 pts).
 
+## Phase W7 — Platform quality: reliability, accessibility, performance, testing
+- [x] Mock API for local development (MSW). Tracked as [issue #95](https://github.com/DocForum/docforum-web/issues/95) (High, 200 pts) — `npm run dev:mock` serves every endpoint the app uses through the normal service layer via `src/mocks/`: seeded obviously-fake fixtures, a dev-panel role switcher (patient/doctor/facility/admin), scenario toggles (empty states, forced errors), a latency slider, and a fixture reset. 26 handler tests drive the real `src/services/` layer against MSW; CI fails if mock code ever enters a production bundle (`npm run check:dist`). Documented in `CONTRIBUTING.md`.
+- [ ] Generate MSW handlers and fixtures from the backend OpenAPI spec. Tracked as [issue #96](https://github.com/DocForum/docforum-web/issues/96) (High, 200 pts) — **blocked**: depends on [docforum-core#112](https://github.com/DocForum/docforum-core/issues/112) (OpenAPI 3.1 spec generated from the Zod schemas), which is still open — there is no authoritative `openapi.json` to generate from yet. Do not fabricate one; see that issue.
+- [ ] Storybook component library with interaction and accessibility tests. Tracked as [issue #97](https://github.com/DocForum/docforum-web/issues/97) (High, 200 pts).
+- [ ] Performance budget: route-level code splitting, lazy GSAP, and Lighthouse CI. Tracked as [issue #99](https://github.com/DocForum/docforum-web/issues/99) (High, 200 pts).
+
 ## Changelog
 - 2026-09-09 — Roadmap created, carved out of docforum-core Phase 7 as part
   of the 3-repo org split.
diff --git a/package-lock.json b/package-lock.json
index fdefee5..5283737 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -23,6 +23,7 @@
         "@types/react-dom": "^19.3.0",
         "@vitejs/plugin-react": "^4.7.0",
         "happy-dom": "^20.14.5",
+        "msw": "^2.15.0",
         "typescript": "^7.0.2",
         "vite": "^6.4.3",
         "vitest": "^4.1.11"
@@ -769,6 +770,93 @@
         "node": ">=18"
       }
     },
+    "node_modules/@inquirer/ansi": {
+      "version": "2.0.9",
+      "resolved": "https://registry.npmjs.org/@inquirer/ansi/-/ansi-2.0.9.tgz",
+      "integrity": "sha512-0Ywt3S8tqM6TWUcsRlBFQ1x+X3/o8kktX0ZiKAnByYb9GFDknnOhse1PVtfiD2BXPI8ar+BWx9PV9R0lQIcygw==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=23.5.0 || ^22.13.0 || ^20.17.0"
+      }
+    },
+    "node_modules/@inquirer/confirm": {
+      "version": "6.3.3",
+      "resolved": "https://registry.npmjs.org/@inquirer/confirm/-/confirm-6.3.3.tgz",
+      "integrity": "sha512-ImOBgpl/sJTFp8naeSkNu4S0Sf8F8pxv3/CUx+LoBAdQvCVqFz6rSB2A/oZYsJge3+yphbEDxEkfaRNYq1OU0A==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@inquirer/core": "^12.0.4",
+        "@inquirer/type": "4.2.0"
+      },
+      "engines": {
+        "node": ">=23.5.0 || ^22.13.0 || ^20.17.0"
+      },
+      "peerDependencies": {
+        "@types/node": ">=18"
+      },
+      "peerDependenciesMeta": {
+        "@types/node": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/@inquirer/core": {
+      "version": "12.0.4",
+      "resolved": "https://registry.npmjs.org/@inquirer/core/-/core-12.0.4.tgz",
+      "integrity": "sha512-M5fB67y7jPObI45vhD82RskWwCSm0scOvenV/I6K8tIi2gfr9DXqQqJ+iw+Wi6SgapikdOiJibYzz1gW47fsDg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@inquirer/ansi": "^2.0.9",
+        "@inquirer/figures": "^2.0.9",
+        "@inquirer/type": "4.2.0",
+        "cli-width": "^4.1.0",
+        "fast-wrap-ansi": "^0.2.0",
+        "mute-stream": "^3.0.0",
+        "signal-exit": "^4.1.0"
+      },
+      "engines": {
+        "node": ">=23.5.0 || ^22.13.0 || ^20.17.0"
+      },
+      "peerDependencies": {
+        "@types/node": ">=18"
+      },
+      "peerDependenciesMeta": {
+        "@types/node": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/@inquirer/figures": {
+      "version": "2.0.9",
+      "resolved": "https://registry.npmjs.org/@inquirer/figures/-/figures-2.0.9.tgz",
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+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=23.5.0 || ^22.13.0 || ^20.17.0"
+      }
+    },
+    "node_modules/@inquirer/type": {
+      "version": "4.2.0",
+      "resolved": "https://registry.npmjs.org/@inquirer/type/-/type-4.2.0.tgz",
+      "integrity": "sha512-2rnHX8RPo4glJYqnFc/v3nQeIhDcjyRRyaT7MGcfL/8xv/8K03SXYoA2tX06WVSKywWOE/ncbG3dtuzLjR5TCQ==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=23.5.0 || ^22.13.0 || ^20.17.0"
+      },
+      "peerDependencies": {
+        "@types/node": ">=18"
+      },
+      "peerDependenciesMeta": {
+        "@types/node": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/@jridgewell/gen-mapping": {
       "version": "0.3.13",
       "resolved": "https://registry.npmjs.org/@jridgewell/gen-mapping/-/gen-mapping-0.3.13.tgz",
@@ -819,6 +907,31 @@
         "@jridgewell/sourcemap-codec": "^1.4.14"
       }
     },
+    "node_modules/@mswjs/interceptors": {
+      "version": "0.41.9",
+      "resolved": "https://registry.npmjs.org/@mswjs/interceptors/-/interceptors-0.41.9.tgz",
+      "integrity": "sha512-VVPPgHyQ6ShqnrmDWuxjmUIsO9gWyOZFmuOfLd9LfBGQJwZfy0gvv9pbHSJuoFNIYC7ZDX9aoFwowjcdSC4E8w==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@open-draft/deferred-promise": "^2.2.0",
+        "@open-draft/logger": "^0.3.0",
+        "@open-draft/until": "^2.0.0",
+        "is-node-process": "^1.2.0",
+        "outvariant": "^1.4.3",
+        "strict-event-emitter": "^0.5.1"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/@mswjs/interceptors/node_modules/@open-draft/deferred-promise": {
+      "version": "2.2.0",
+      "resolved": "https://registry.npmjs.org/@open-draft/deferred-promise/-/deferred-promise-2.2.0.tgz",
+      "integrity": "sha512-CecwLWx3rhxVQF6V4bAgPS5t+So2sTbPgAzafKkVizyi7tlwpcFpdFqq+wqF2OwNBmqFuu6tOyouTuxgpMfzmA==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@napi-rs/lzma-linux-x64-gnu": {
       "version": "1.5.1",
       "resolved": "https://registry.npmjs.org/@napi-rs/lzma-linux-x64-gnu/-/lzma-linux-x64-gnu-1.5.1.tgz",
@@ -836,6 +949,31 @@
         "node": "^22.20 || ^24.12 || >=25"
       }
     },
+    "node_modules/@open-draft/deferred-promise": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/@open-draft/deferred-promise/-/deferred-promise-3.0.0.tgz",
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+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/@open-draft/logger": {
+      "version": "0.3.0",
+      "resolved": "https://registry.npmjs.org/@open-draft/logger/-/logger-0.3.0.tgz",
+      "integrity": "sha512-X2g45fzhxH238HKO4xbSr7+wBS8Fvw6ixhTDuvLd5mqh6bJJCFAPwU9mPDxbcrRtfxv4u5IHCEH77BmxvXmmxQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "is-node-process": "^1.2.0",
+        "outvariant": "^1.4.0"
+      }
+    },
+    "node_modules/@open-draft/until": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/@open-draft/until/-/until-2.1.0.tgz",
+      "integrity": "sha512-U69T3ItWHvLwGg5eJ0n3I62nWuE6ilHlmz7zM0npLBRvPRd7e6NYmg54vvRtP5mZG7kZqZCFVdsTWo7BPtBujg==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@rolldown/pluginutils": {
       "version": "1.0.0-beta.27",
       "resolved": "https://registry.npmjs.org/@rolldown/pluginutils/-/pluginutils-1.0.0-beta.27.tgz",
@@ -1424,6 +1562,23 @@
         "@types/react": "^19.3.0"
       }
     },
+    "node_modules/@types/set-cookie-parser": {
+      "version": "2.4.10",
+      "resolved": "https://registry.npmjs.org/@types/set-cookie-parser/-/set-cookie-parser-2.4.10.tgz",
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+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/node": "*"
+      }
+    },
+    "node_modules/@types/statuses": {
+      "version": "2.0.6",
+      "resolved": "https://registry.npmjs.org/@types/statuses/-/statuses-2.0.6.tgz",
+      "integrity": "sha512-xMAgYwceFhRA2zY+XbEA7mxYbA093wdiW8Vu6gZPGWy9cmOyU9XesH1tNcEWsKFd5Vzrqx5T3D38PWx1FIIXkA==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/@types/whatwg-mimetype": {
       "version": "3.0.2",
       "resolved": "https://registry.npmjs.org/@types/whatwg-mimetype/-/whatwg-mimetype-3.0.2.tgz",
@@ -1921,7 +2076,6 @@
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-      "peer": true,
       "engines": {
         "node": ">=8"
       }
@@ -2051,6 +2205,51 @@
         "node": ">=18"
       }
     },
+    "node_modules/cli-width": {
+      "version": "4.1.0",
+      "resolved": "https://registry.npmjs.org/cli-width/-/cli-width-4.1.0.tgz",
+      "integrity": "sha512-ouuZd4/dm2Sw5Gmqy6bGyNNNe1qt9RpmxveLSO7KcgsTnU7RXfsw+/bukWGo1abgBiMAic068rclZsO4IWmmxQ==",
+      "dev": true,
+      "license": "ISC",
+      "engines": {
+        "node": ">= 12"
+      }
+    },
+    "node_modules/cliui": {
+      "version": "8.0.1",
+      "resolved": "https://registry.npmjs.org/cliui/-/cliui-8.0.1.tgz",
+      "integrity": "sha512-BSeNnyus75C4//NQ9gQt1/csTXyo/8Sb+afLAkzAptFuMsod9HFokGNudZpi/oQV73hnVK+sR+5PVRMd+Dr7YQ==",
+      "dev": true,
+      "license": "ISC",
+      "dependencies": {
+        "string-width": "^4.2.0",
+        "strip-ansi": "^6.0.1",
+        "wrap-ansi": "^7.0.0"
+      },
+      "engines": {
+        "node": ">=12"
+      }
+    },
+    "node_modules/color-convert": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/color-convert/-/color-convert-2.0.1.tgz",
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+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "color-name": "~1.1.4"
+      },
+      "engines": {
+        "node": ">=7.0.0"
+      }
+    },
+    "node_modules/color-name": {
+      "version": "1.1.4",
+      "resolved": "https://registry.npmjs.org/color-name/-/color-name-1.1.4.tgz",
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+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/convert-source-map": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/convert-source-map/-/convert-source-map-2.0.0.tgz",
@@ -2128,6 +2327,13 @@
       "dev": true,
       "license": "ISC"
     },
+    "node_modules/emoji-regex": {
+      "version": "8.0.0",
+      "resolved": "https://registry.npmjs.org/emoji-regex/-/emoji-regex-8.0.0.tgz",
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+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/es-module-lexer": {
       "version": "2.3.2",
       "resolved": "https://registry.npmjs.org/es-module-lexer/-/es-module-lexer-2.3.2.tgz",
@@ -2207,6 +2413,33 @@
         "node": ">=12.0.0"
       }
     },
+    "node_modules/fast-string-truncated-width": {
+      "version": "3.0.3",
+      "resolved": "https://registry.npmjs.org/fast-string-truncated-width/-/fast-string-truncated-width-3.0.3.tgz",
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+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/fast-string-width": {
+      "version": "3.0.2",
+      "resolved": "https://registry.npmjs.org/fast-string-width/-/fast-string-width-3.0.2.tgz",
+      "integrity": "sha512-gX8LrtNEI5hq8DVUfRQMbr5lpaS4nMIWV+7XEbXk2b8kiQIizgnlr12B4dA3ZEx3308ze0O4Q1R+cHts8kyUJg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "fast-string-truncated-width": "^3.0.2"
+      }
+    },
+    "node_modules/fast-wrap-ansi": {
+      "version": "0.2.2",
+      "resolved": "https://registry.npmjs.org/fast-wrap-ansi/-/fast-wrap-ansi-0.2.2.tgz",
+      "integrity": "sha512-7F2Fl+TjRSenLqlU3UjSH0iyqopqoZIu7eZVpEirP2g1GtWa2G/ecEmBdgz31+Mxr+ELclgg6sokpSFIQiZ02Q==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "fast-string-width": "^3.0.2"
+      }
+    },
     "node_modules/fdir": {
       "version": "6.5.0",
       "resolved": "https://registry.npmjs.org/fdir/-/fdir-6.5.0.tgz",
@@ -2250,6 +2483,26 @@
         "node": ">=6.9.0"
       }
     },
+    "node_modules/get-caller-file": {
+      "version": "2.0.5",
+      "resolved": "https://registry.npmjs.org/get-caller-file/-/get-caller-file-2.0.5.tgz",
+      "integrity": "sha512-DyFP3BM/3YHTQOCUL/w0OZHR0lpKeGrxotcHWcqNEdnltqFwXVfhEBQ94eIo34AfQpo0rGki4cyIiftY06h2Fg==",
+      "dev": true,
+      "license": "ISC",
+      "engines": {
+        "node": "6.* || 8.* || >= 10.*"
+      }
+    },
+    "node_modules/graphql": {
+      "version": "16.14.2",
+      "resolved": "https://registry.npmjs.org/graphql/-/graphql-16.14.2.tgz",
+      "integrity": "sha512-Chq1s4CY7jmh8gO2qvLIJyfCDIN+EHLFW/9iShnp1z8FjBQMoodWP1kDC36VAMXXIvAjj4ARa7ntfAV2BrjsbA==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": "^12.22.0 || ^14.16.0 || ^16.0.0 || >=17.0.0"
+      }
+    },
     "node_modules/gsap": {
       "version": "3.15.0",
       "resolved": "https://registry.npmjs.org/gsap/-/gsap-3.15.0.tgz",
@@ -2298,6 +2551,24 @@
         "node": ">=12"
       }
     },
+    "node_modules/headers-polyfill": {
+      "version": "5.0.1",
+      "resolved": "https://registry.npmjs.org/headers-polyfill/-/headers-polyfill-5.0.1.tgz",
+      "integrity": "sha512-1TJ6Fih/b8h5TIcv+1+Hw0PDQWJTKDKzFZzcKOiW1wJza3XoAQlkCuXLbymPYB8+ZQyw8mHvdw560e8zVFIWyA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/set-cookie-parser": "^2.4.10",
+        "set-cookie-parser": "^3.0.1"
+      }
+    },
+    "node_modules/headers-polyfill/node_modules/set-cookie-parser": {
+      "version": "3.1.4",
+      "resolved": "https://registry.npmjs.org/set-cookie-parser/-/set-cookie-parser-3.1.4.tgz",
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+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/indent-string": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/indent-string/-/indent-string-4.0.0.tgz",
@@ -2308,6 +2579,23 @@
         "node": ">=8"
       }
     },
+    "node_modules/is-fullwidth-code-point": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/is-fullwidth-code-point/-/is-fullwidth-code-point-3.0.0.tgz",
+      "integrity": "sha512-zymm5+u+sCsSWyD9qNaejV3DFvhCKclKdizYaJUuHA83RLjb7nSuGnddCHGv0hk+KY7BMAlsWeK4Ueg6EV6XQg==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=8"
+      }
+    },
+    "node_modules/is-node-process": {
+      "version": "1.2.0",
+      "resolved": "https://registry.npmjs.org/is-node-process/-/is-node-process-1.2.0.tgz",
+      "integrity": "sha512-Vg4o6/fqPxIjtxgUH5QLJhwZ7gW5diGCVlXpuUfELC62CuxM1iHcRe51f2W1FDy04Ai4KJkagKjx3XaqyfRKXw==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/js-tokens": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/js-tokens/-/js-tokens-4.0.0.tgz",
@@ -2389,6 +2677,61 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/msw": {
+      "version": "2.15.0",
+      "resolved": "https://registry.npmjs.org/msw/-/msw-2.15.0.tgz",
+      "integrity": "sha512-2wQAmKkQKxRuXvYJxVhPGG0wZNBQyD06oJvxqw90XqLvptdqxdlHrFUfEteKkpaNORX3Xzc+HtEl/q0nfmN2wQ==",
+      "dev": true,
+      "hasInstallScript": true,
+      "license": "MIT",
+      "dependencies": {
+        "@inquirer/confirm": "^6.0.11",
+        "@mswjs/interceptors": "^0.41.3",
+        "@open-draft/deferred-promise": "^3.0.0",
+        "@types/statuses": "^2.0.6",
+        "cookie": "^1.1.1",
+        "graphql": "^16.13.2",
+        "headers-polyfill": "^5.0.1",
+        "is-node-process": "^1.2.0",
+        "outvariant": "^1.4.3",
+        "path-to-regexp": "^6.3.0",
+        "picocolors": "^1.1.1",
+        "rettime": "^0.11.11",
+        "statuses": "^2.0.2",
+        "strict-event-emitter": "^0.5.1",
+        "tough-cookie": "^6.0.1",
+        "type-fest": "^5.5.0",
+        "until-async": "^3.0.2",
+        "yargs": "^17.7.2"
+      },
+      "bin": {
+        "msw": "cli/index.js"
+      },
+      "engines": {
+        "node": ">=18"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/mswjs"
+      },
+      "peerDependencies": {
+        "typescript": ">= 4.8.x"
+      },
+      "peerDependenciesMeta": {
+        "typescript": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/mute-stream": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/mute-stream/-/mute-stream-3.0.0.tgz",
+      "integrity": "sha512-dkEJPVvun4FryqBmZ5KhDo0K9iDXAwn08tMLDinNdRBNPcYEDiWYysLcc6k3mjTMlbP9KyylvRpd4wFtwrT9rw==",
+      "dev": true,
+      "license": "ISC",
+      "engines": {
+        "node": "^20.17.0 || >=22.9.0"
+      }
+    },
     "node_modules/nanoid": {
       "version": "3.3.19",
       "resolved": "https://registry.npmjs.org/nanoid/-/nanoid-3.3.19.tgz",
@@ -2432,6 +2775,20 @@
         "node": ">=12.20.0"
       }
     },
+    "node_modules/outvariant": {
+      "version": "1.4.3",
+      "resolved": "https://registry.npmjs.org/outvariant/-/outvariant-1.4.3.tgz",
+      "integrity": "sha512-+Sl2UErvtsoajRDKCE5/dBz4DIvHXQQnAxtQTF04OJxY0+DyZXSo5P5Bb7XYWOh81syohlYL24hbDwxedPUJCA==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/path-to-regexp": {
+      "version": "6.3.0",
+      "resolved": "https://registry.npmjs.org/path-to-regexp/-/path-to-regexp-6.3.0.tgz",
+      "integrity": "sha512-Yhpw4T9C6hPpgPeA28us07OJeqZ5EzQTkbfwuhsUg0c237RomFoETJgmp2sa3F/41gfLE6G5cqcYwznmeEeOlQ==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/pathe": {
       "version": "2.0.3",
       "resolved": "https://registry.npmjs.org/pathe/-/pathe-2.0.3.tgz",
@@ -2595,6 +2952,23 @@
         "node": ">=8"
       }
     },
+    "node_modules/require-directory": {
+      "version": "2.1.1",
+      "resolved": "https://registry.npmjs.org/require-directory/-/require-directory-2.1.1.tgz",
+      "integrity": "sha512-fGxEI7+wsG9xrvdjsrlmL22OMTTiHRwAMroiEeMgq8gzoLC/PQr7RsRDSTLUg/bZAZtF+TVIkHc6/4RIKrui+Q==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=0.10.0"
+      }
+    },
+    "node_modules/rettime": {
+      "version": "0.11.12",
+      "resolved": "https://registry.npmjs.org/rettime/-/rettime-0.11.12.tgz",
+      "integrity": "sha512-5ExtR1ppiDBQkVoPw5NAqdbfH4Iq2VOmQKHMtUoaFxA9bo2krzFYBtyq6K40xxbYp+2w/YOr6D+1ToF6tTN53A==",
+      "dev": true,
+      "license": "MIT"
+    },
     "node_modules/rollup": {
       "version": "4.63.2",
       "resolved": "https://registry.npmjs.org/rollup/-/rollup-4.63.2.tgz",
@@ -2670,6 +3044,19 @@
       "dev": true,
       "license": "ISC"
     },
+    "node_modules/signal-exit": {
+      "version": "4.1.0",
+      "resolved": "https://registry.npmjs.org/signal-exit/-/signal-exit-4.1.0.tgz",
+      "integrity": "sha512-bzyZ1e88w9O1iNJbKnOlvYTrWPDl46O1bG0D3XInv+9tkPrxrN8jUUTiFlDkkmKWgn1M6CfIA13SuGqOa9Korw==",
+      "dev": true,
+      "license": "ISC",
+      "engines": {
+        "node": ">=14"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/isaacs"
+      }
+    },
     "node_modules/source-map-js": {
       "version": "1.2.1",
       "resolved": "https://registry.npmjs.org/source-map-js/-/source-map-js-1.2.1.tgz",
@@ -2687,6 +3074,16 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/statuses": {
+      "version": "2.0.2",
+      "resolved": "https://registry.npmjs.org/statuses/-/statuses-2.0.2.tgz",
+      "integrity": "sha512-DvEy55V3DB7uknRo+4iOGT5fP1slR8wQohVdknigZPMpMstaKJQWhwiYBACJE3Ul2pTnATihhBYnRhZQHGBiRw==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">= 0.8"
+      }
+    },
     "node_modules/std-env": {
       "version": "4.2.0",
       "resolved": "https://registry.npmjs.org/std-env/-/std-env-4.2.0.tgz",
@@ -2694,6 +3091,41 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/strict-event-emitter": {
+      "version": "0.5.1",
+      "resolved": "https://registry.npmjs.org/strict-event-emitter/-/strict-event-emitter-0.5.1.tgz",
+      "integrity": "sha512-vMgjE/GGEPEFnhFub6pa4FmJBRBVOLpIII2hvCZ8Kzb7K0hlHo7mQv6xYrBvCL2LtAIBwFUK8wvuJgTVSQ5MFQ==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/string-width": {
+      "version": "4.2.3",
+      "resolved": "https://registry.npmjs.org/string-width/-/string-width-4.2.3.tgz",
+      "integrity": "sha512-wKyQRQpjJ0sIp62ErSZdGsjMJWsap5oRNihHhu6G7JVO/9jIB6UyevL+tXuOqrng8j/cxKTWyWUwvSTriiZz/g==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "emoji-regex": "^8.0.0",
+        "is-fullwidth-code-point": "^3.0.0",
+        "strip-ansi": "^6.0.1"
+      },
+      "engines": {
+        "node": ">=8"
+      }
+    },
+    "node_modules/strip-ansi": {
+      "version": "6.0.1",
+      "resolved": "https://registry.npmjs.org/strip-ansi/-/strip-ansi-6.0.1.tgz",
+      "integrity": "sha512-Y38VPSHcqkFrCpFnQ9vuSXmquuv5oXOKpGeT6aGrr3o3Gc9AlVa6JBfUSOCnbxGGZF+/0ooI7KrPuUSztUdU5A==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "ansi-regex": "^5.0.1"
+      },
+      "engines": {
+        "node": ">=8"
+      }
+    },
     "node_modules/strip-indent": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/strip-indent/-/strip-indent-3.0.0.tgz",
@@ -2707,6 +3139,19 @@
         "node": ">=8"
       }
     },
+    "node_modules/tagged-tag": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/tagged-tag/-/tagged-tag-1.0.0.tgz",
+      "integrity": "sha512-yEFYrVhod+hdNyx7g5Bnkkb0G6si8HJurOoOEgC8B/O0uXLHlaey/65KRv6cuWBNhBgHKAROVpc7QyYqE5gFng==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=20"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
     "node_modules/tinybench": {
       "version": "2.9.0",
       "resolved": "https://registry.npmjs.org/tinybench/-/tinybench-2.9.0.tgz",
@@ -2751,6 +3196,55 @@
         "node": ">=14.0.0"
       }
     },
+    "node_modules/tldts": {
+      "version": "7.4.18",
+      "resolved": "https://registry.npmjs.org/tldts/-/tldts-7.4.18.tgz",
+      "integrity": "sha512-somxA8xKAUzlAxl0TX/jMSYIbRNFIVGnI96pVGJPeMc5BsHmfVXn6mOJT6U++ELnl04eGfzpfcEuZe8WiASkXg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "tldts-core": "^7.4.18"
+      },
+      "bin": {
+        "tldts": "bin/cli.js"
+      }
+    },
+    "node_modules/tldts-core": {
+      "version": "7.4.18",
+      "resolved": "https://registry.npmjs.org/tldts-core/-/tldts-core-7.4.18.tgz",
+      "integrity": "sha512-KI2PKvCmvQI/xD6ypPqkU0i7oxNXR/O58RLRaHR4svsgVUQ2JE/XC8BtMbG6PSehD27I8sZJRcC1ASnCy6lp3g==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/tough-cookie": {
+      "version": "6.0.2",
+      "resolved": "https://registry.npmjs.org/tough-cookie/-/tough-cookie-6.0.2.tgz",
+      "integrity": "sha512-exgYmnmL/sJpR3upZfXG5PoatXQii55xAiXGXzY+sROLZ/Y+SLcp9PgJNI9Vz37HpQ74WvDcLT8eqm+kV3FzrA==",
+      "dev": true,
+      "license": "BSD-3-Clause",
+      "dependencies": {
+        "tldts": "^7.0.5"
+      },
+      "engines": {
+        "node": ">=16"
+      }
+    },
+    "node_modules/type-fest": {
+      "version": "5.10.0",
+      "resolved": "https://registry.npmjs.org/type-fest/-/type-fest-5.10.0.tgz",
+      "integrity": "sha512-NoSdpq/WEiAg5sjmBkmV/hfxv6HJH4NqPNrqjtSO5CwRmpsDfaf4begxW34KdJykH/l1yHtwBWQkCRdoXO8mPA==",
+      "dev": true,
+      "license": "(MIT OR CC0-1.0)",
+      "dependencies": {
+        "tagged-tag": "^1.0.0"
+      },
+      "engines": {
+        "node": ">=20"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/sindresorhus"
+      }
+    },
     "node_modules/typescript": {
       "version": "7.0.2",
       "resolved": "https://registry.npmjs.org/typescript/-/typescript-7.0.2.tgz",
@@ -2793,6 +3287,16 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/until-async": {
+      "version": "3.0.2",
+      "resolved": "https://registry.npmjs.org/until-async/-/until-async-3.0.2.tgz",
+      "integrity": "sha512-IiSk4HlzAMqTUseHHe3VhIGyuFmN90zMTpD3Z3y8jeQbzLIq500MVM7Jq2vUAnTKAFPJrqwkzr6PoTcPhGcOiw==",
+      "dev": true,
+      "license": "MIT",
+      "funding": {
+        "url": "https://github.com/sponsors/kettanaito"
+      }
+    },
     "node_modules/update-browserslist-db": {
       "version": "1.3.3",
       "resolved": "https://registry.npmjs.org/update-browserslist-db/-/update-browserslist-db-1.3.3.tgz",
@@ -3006,6 +3510,40 @@
         "node": ">=8"
       }
     },
+    "node_modules/wrap-ansi": {
+      "version": "7.0.0",
+      "resolved": "https://registry.npmjs.org/wrap-ansi/-/wrap-ansi-7.0.0.tgz",
+      "integrity": "sha512-YVGIj2kamLSTxw6NsZjoBxfSwsn0ycdesmc4p+Q21c5zPuZ1pl+NfxVdxPtdHvmNVOQ6XSYG4AUtyt/Fi7D16Q==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "ansi-styles": "^4.0.0",
+        "string-width": "^4.1.0",
+        "strip-ansi": "^6.0.0"
+      },
+      "engines": {
+        "node": ">=10"
+      },
+      "funding": {
+        "url": "https://github.com/chalk/wrap-ansi?sponsor=1"
+      }
+    },
+    "node_modules/wrap-ansi/node_modules/ansi-styles": {
+      "version": "4.3.0",
+      "resolved": "https://registry.npmjs.org/ansi-styles/-/ansi-styles-4.3.0.tgz",
+      "integrity": "sha512-zbB9rCJAT1rbjiVDb2hqKFHNYLxgtk8NURxZ3IZwD3F6NtxbXZQCnnSi1Lkx+IDohdPlFp222wVALIheZJQSEg==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "color-convert": "^2.0.1"
+      },
+      "engines": {
+        "node": ">=8"
+      },
+      "funding": {
+        "url": "https://github.com/chalk/ansi-styles?sponsor=1"
+      }
+    },
     "node_modules/ws": {
       "version": "8.21.3",
       "resolved": "https://registry.npmjs.org/ws/-/ws-8.21.3.tgz",
@@ -3028,6 +3566,16 @@
         }
       }
     },
+    "node_modules/y18n": {
+      "version": "5.0.8",
+      "resolved": "https://registry.npmjs.org/y18n/-/y18n-5.0.8.tgz",
+      "integrity": "sha512-0pfFzegeDWJHJIAmTLRP2DwHjdF5s7jo9tuztdQxAhINCdvS+3nGINqPd00AphqJR/0LhANUS6/+7SCb98YOfA==",
+      "dev": true,
+      "license": "ISC",
+      "engines": {
+        "node": ">=10"
+      }
+    },
     "node_modules/yallist": {
       "version": "3.1.1",
       "resolved": "https://registry.npmjs.org/yallist/-/yallist-3.1.1.tgz",
@@ -3035,6 +3583,35 @@
       "dev": true,
       "license": "ISC"
     },
+    "node_modules/yargs": {
+      "version": "17.7.3",
+      "resolved": "https://registry.npmjs.org/yargs/-/yargs-17.7.3.tgz",
+      "integrity": "sha512-GZtjxm/J/4TSxuL3FNYjCmLktBTnIw/rVmKSIyKeYAZpmJB2ig9VauCC5xsa82GNKVKDAqpOn3KVzNt0zmrU0g==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "cliui": "^8.0.1",
+        "escalade": "^3.1.1",
+        "get-caller-file": "^2.0.5",
+        "require-directory": "^2.1.1",
+        "string-width": "^4.2.3",
+        "y18n": "^5.0.5",
+        "yargs-parser": "^21.1.1"
+      },
+      "engines": {
+        "node": ">=12"
+      }
+    },
+    "node_modules/yargs-parser": {
+      "version": "21.1.1",
+      "resolved": "https://registry.npmjs.org/yargs-parser/-/yargs-parser-21.1.1.tgz",
+      "integrity": "sha512-tVpsJW7DdjecAiFpbIB1e3qxIQsE6NoPc5/eTdrbbIC4h0LVsWhnoa3g+m2HclBIujHzsxZ4VJVA+GUuc2/LBw==",
+      "dev": true,
+      "license": "ISC",
+      "engines": {
+        "node": ">=12"
+      }
+    },
     "node_modules/zustand": {
       "version": "5.0.15",
       "resolved": "https://registry.npmjs.org/zustand/-/zustand-5.0.15.tgz",
diff --git a/package.json b/package.json
index 399f8e9..207a770 100644
--- a/package.json
+++ b/package.json
@@ -5,8 +5,10 @@
   "type": "module",
   "scripts": {
     "dev": "vite",
+    "dev:mock": "VITE_ENABLE_MOCKS=true vite",
     "build": "tsc -b && vite build",
     "build:pages": "tsc -b && GITHUB_PAGES=true vite build",
+    "check:dist": "node scripts/check-dist-no-mocks.mjs",
     "preview": "vite preview",
     "typecheck": "tsc -b --noEmit",
     "test": "vitest run"
@@ -27,6 +29,7 @@
     "@types/react-dom": "^19.3.0",
     "@vitejs/plugin-react": "^4.7.0",
     "happy-dom": "^20.14.5",
+    "msw": "^2.15.0",
     "typescript": "^7.0.2",
     "vite": "^6.4.3",
     "vitest": "^4.1.11"
diff --git a/public/mockServiceWorker.js b/public/mockServiceWorker.js
new file mode 100644
index 0000000..0c970ef
--- /dev/null
+++ b/public/mockServiceWorker.js
@@ -0,0 +1,361 @@
+/* eslint-disable */
+/* tslint:disable */
+
+/**
+ * Mock Service Worker.
+ * @see https://github.com/mswjs/msw
+ * - Please do NOT modify this file.
+ */
+
+const PACKAGE_VERSION = '2.15.0'
+const INTEGRITY_CHECKSUM = '03cb67ac84128e63d7cd722a6e5b7f1e'
+const IS_MOCKED_RESPONSE = Symbol('isMockedResponse')
+const activeClientIds = new Set()
+
+addEventListener('install', function () {
+  self.skipWaiting()
+})
+
+addEventListener('activate', function (event) {
+  event.waitUntil(self.clients.claim())
+})
+
+addEventListener('message', async function (event) {
+  const clientId = Reflect.get(event.source || {}, 'id')
+
+  if (!clientId || !self.clients) {
+    return
+  }
+
+  const client = await self.clients.get(clientId)
+
+  if (!client) {
+    return
+  }
+
+  const allClients = await self.clients.matchAll({
+    type: 'window',
+  })
+
+  switch (event.data) {
+    case 'KEEPALIVE_REQUEST': {
+      sendToClient(client, {
+        type: 'KEEPALIVE_RESPONSE',
+      })
+      break
+    }
+
+    case 'INTEGRITY_CHECK_REQUEST': {
+      sendToClient(client, {
+        type: 'INTEGRITY_CHECK_RESPONSE',
+        payload: {
+          packageVersion: PACKAGE_VERSION,
+          checksum: INTEGRITY_CHECKSUM,
+        },
+      })
+      break
+    }
+
+    case 'MOCK_ACTIVATE': {
+      activeClientIds.add(clientId)
+
+      sendToClient(client, {
+        type: 'MOCKING_ENABLED',
+        payload: {
+          client: {
+            id: client.id,
+            frameType: client.frameType,
+          },
+        },
+      })
+      break
+    }
+
+    case 'CLIENT_CLOSED': {
+      activeClientIds.delete(clientId)
+
+      const remainingClients = allClients.filter((client) => {
+        return client.id !== clientId
+      })
+
+      // Unregister itself when there are no more clients
+      if (remainingClients.length === 0) {
+        self.registration.unregister()
+      }
+
+      break
+    }
+  }
+})
+
+addEventListener('fetch', function (event) {
+  const requestInterceptedAt = Date.now()
+
+  // Bypass navigation requests.
+  if (event.request.mode === 'navigate') {
+    return
+  }
+
+  // Opening the DevTools triggers the "only-if-cached" request
+  // that cannot be handled by the worker. Bypass such requests.
+  if (
+    event.request.cache === 'only-if-cached' &&
+    event.request.mode !== 'same-origin'
+  ) {
+    return
+  }
+
+  // Bypass all requests when there are no active clients.
+  // Prevents the self-unregistered worked from handling requests
+  // after it's been terminated (still remains active until the next reload).
+  if (activeClientIds.size === 0) {
+    return
+  }
+
+  const requestId = crypto.randomUUID()
+  event.respondWith(handleRequest(event, requestId, requestInterceptedAt))
+})
+
+/**
+ * @param {FetchEvent} event
+ * @param {string} requestId
+ * @param {number} requestInterceptedAt
+ */
+async function handleRequest(event, requestId, requestInterceptedAt) {
+  const client = await resolveMainClient(event)
+  const requestCloneForEvents = event.request.clone()
+  const response = await getResponse(
+    event,
+    client,
+    requestId,
+    requestInterceptedAt,
+  )
+
+  // Send back the response clone for the "response:*" life-cycle events.
+  // Ensure MSW is active and ready to handle the message, otherwise
+  // this message will pend indefinitely.
+  if (client && activeClientIds.has(client.id)) {
+    const serializedRequest = await serializeRequest(requestCloneForEvents)
+
+    // Omit the body of server-sent event stream responses.
+    // Cloning such responses would prevent client-side stream cancelations
+    // from reaching the original stream (a teed stream only cancels its
+    // source once both of its branches cancel) and would buffer the
+    // entire stream into the unconsumed clone indefinitely.
+    const isEventStreamResponse = response.headers
+      .get('content-type')
+      ?.toLowerCase()
+      .startsWith('text/event-stream')
+
+    // Clone the response so both the client and the library could consume it.
+    const responseClone = isEventStreamResponse ? null : response.clone()
+
+    sendToClient(
+      client,
+      {
+        type: 'RESPONSE',
+        payload: {
+          isMockedResponse: IS_MOCKED_RESPONSE in response,
+          request: {
+            id: requestId,
+            ...serializedRequest,
+          },
+          response: {
+            type: response.type,
+            status: response.status,
+            statusText: response.statusText,
+            headers: Object.fromEntries(response.headers.entries()),
+            body: responseClone ? responseClone.body : null,
+          },
+        },
+      },
+      responseClone && responseClone.body
+        ? [serializedRequest.body, responseClone.body]
+        : [],
+    )
+  }
+
+  return response
+}
+
+/**
+ * Resolve the main client for the given event.
+ * Client that issues a request doesn't necessarily equal the client
+ * that registered the worker. It's with the latter the worker should
+ * communicate with during the response resolving phase.
+ * @param {FetchEvent} event
+ * @returns {Promise<Client | undefined>}
+ */
+async function resolveMainClient(event) {
+  const client = await self.clients.get(event.clientId)
+
+  if (activeClientIds.has(event.clientId)) {
+    return client
+  }
+
+  if (client?.frameType === 'top-level') {
+    return client
+  }
+
+  const allClients = await self.clients.matchAll({
+    type: 'window',
+  })
+
+  return allClients
+    .filter((client) => {
+      // Get only those clients that are currently visible.
+      return client.visibilityState === 'visible'
+    })
+    .find((client) => {
+      // Find the client ID that's recorded in the
+      // set of clients that have registered the worker.
+      return activeClientIds.has(client.id)
+    })
+}
+
+/**
+ * @param {FetchEvent} event
+ * @param {Client | undefined} client
+ * @param {string} requestId
+ * @param {number} requestInterceptedAt
+ * @returns {Promise<Response>}
+ */
+async function getResponse(event, client, requestId, requestInterceptedAt) {
+  // Clone the request because it might've been already used
+  // (i.e. its body has been read and sent to the client).
+  const requestClone = event.request.clone()
+
+  function passthrough() {
+    // Cast the request headers to a new Headers instance
+    // so the headers can be manipulated with.
+    const headers = new Headers(requestClone.headers)
+
+    // Remove the "accept" header value that marked this request as passthrough.
+    // This prevents request alteration and also keeps it compliant with the
+    // user-defined CORS policies.
+    const acceptHeader = headers.get('accept')
+    if (acceptHeader) {
+      const values = acceptHeader.split(',').map((value) => value.trim())
+      const filteredValues = values.filter(
+        (value) => value !== 'msw/passthrough',
+      )
+
+      if (filteredValues.length > 0) {
+        headers.set('accept', filteredValues.join(', '))
+      } else {
+        headers.delete('accept')
+      }
+    }
+
+    return fetch(requestClone, { headers })
+  }
+
+  // Bypass mocking when the client is not active.
+  if (!client) {
+    return passthrough()
+  }
+
+  // Bypass initial page load requests (i.e. static assets).
+  // The absence of the immediate/parent client in the map of the active clients
+  // means that MSW hasn't dispatched the "MOCK_ACTIVATE" event yet
+  // and is not ready to handle requests.
+  if (!activeClientIds.has(client.id)) {
+    return passthrough()
+  }
+
+  // Notify the client that a request has been intercepted.
+  const serializedRequest = await serializeRequest(event.request)
+  const clientMessage = await sendToClient(
+    client,
+    {
+      type: 'REQUEST',
+      payload: {
+        id: requestId,
+        interceptedAt: requestInterceptedAt,
+        ...serializedRequest,
+      },
+    },
+    [serializedRequest.body],
+  )
+
+  switch (clientMessage.type) {
+    case 'MOCK_RESPONSE': {
+      return respondWithMock(clientMessage.data)
+    }
+
+    case 'PASSTHROUGH': {
+      return passthrough()
+    }
+  }
+
+  return passthrough()
+}
+
+/**
+ * @param {Client} client
+ * @param {any} message
+ * @param {Array<Transferable>} transferrables
+ * @returns {Promise<any>}
+ */
+function sendToClient(client, message, transferrables = []) {
+  return new Promise((resolve, reject) => {
+    const channel = new MessageChannel()
+
+    channel.port1.onmessage = (event) => {
+      if (event.data && event.data.error) {
+        return reject(event.data.error)
+      }
+
+      resolve(event.data)
+    }
+
+    client.postMessage(message, [
+      channel.port2,
+      ...transferrables.filter(Boolean),
+    ])
+  })
+}
+
+/**
+ * @param {Response} response
+ * @returns {Response}
+ */
+function respondWithMock(response) {
+  // Setting response status code to 0 is a no-op.
+  // However, when responding with a "Response.error()", the produced Response
+  // instance will have status code set to 0. Since it's not possible to create
+  // a Response instance with status code 0, handle that use-case separately.
+  if (response.status === 0) {
+    return Response.error()
+  }
+
+  const mockedResponse = new Response(response.body, response)
+
+  Reflect.defineProperty(mockedResponse, IS_MOCKED_RESPONSE, {
+    value: true,
+    enumerable: true,
+  })
+
+  return mockedResponse
+}
+
+/**
+ * @param {Request} request
+ */
+async function serializeRequest(request) {
+  return {
+    url: request.url,
+    mode: request.mode,
+    method: request.method,
+    headers: Object.fromEntries(request.headers.entries()),
+    cache: request.cache,
+    credentials: request.credentials,
+    destination: request.destination,
+    integrity: request.integrity,
+    redirect: request.redirect,
+    referrer: request.referrer,
+    referrerPolicy: request.referrerPolicy,
+    body: await request.arrayBuffer(),
+    keepalive: request.keepalive,
+  }
+}
diff --git a/screenshots/mock-dev-panel-desktop.png b/screenshots/mock-dev-panel-desktop.png
new file mode 100644
index 0000000..a4545be
Binary files /dev/null and b/screenshots/mock-dev-panel-desktop.png differ
diff --git a/screenshots/mock-dev-panel-mobile.png b/screenshots/mock-dev-panel-mobile.png
new file mode 100644
index 0000000..71a53b2
Binary files /dev/null and b/screenshots/mock-dev-panel-mobile.png differ
diff --git a/screenshots/mock-doctor-dashboard-desktop.png b/screenshots/mock-doctor-dashboard-desktop.png
new file mode 100644
index 0000000..58d8f94
Binary files /dev/null and b/screenshots/mock-doctor-dashboard-desktop.png differ
diff --git a/screenshots/mock-patient-dashboard-mobile.png b/screenshots/mock-patient-dashboard-mobile.png
new file mode 100644
index 0000000..2ee41ab
Binary files /dev/null and b/screenshots/mock-patient-dashboard-mobile.png differ
diff --git a/screenshots/mock-patient-dependents-desktop.png b/screenshots/mock-patient-dependents-desktop.png
new file mode 100644
index 0000000..7b71898
Binary files /dev/null and b/screenshots/mock-patient-dependents-desktop.png differ
diff --git a/screenshots/mock-scenario-empty-desktop.png b/screenshots/mock-scenario-empty-desktop.png
new file mode 100644
index 0000000..83cc811
Binary files /dev/null and b/screenshots/mock-scenario-empty-desktop.png differ
diff --git a/screenshots/mock-scenario-error-desktop.png b/screenshots/mock-scenario-error-desktop.png
new file mode 100644
index 0000000..26bcd80
Binary files /dev/null and b/screenshots/mock-scenario-error-desktop.png differ
diff --git a/scripts/check-dist-no-mocks.mjs b/scripts/check-dist-no-mocks.mjs
new file mode 100644
index 0000000..0083060
--- /dev/null
+++ b/scripts/check-dist-no-mocks.mjs
@@ -0,0 +1,49 @@
+// Fails (exit 1) if any string that only exists inside src/mocks/** shows
+// up in the production bundle in dist/. Run as `npm run check:dist` after
+// `npm run build`; wired into CI so mock-mode code can never silently
+// ship to production (issue #95).
+import { readdirSync, readFileSync } from 'node:fs';
+import { join } from 'node:path';
+
+const DIST = join(process.cwd(), 'dist');
+
+// Unique literals from src/mocks/** — one per mock-only module.
+const FORBIDDEN_MARKERS = [
+  'Mock scenario: forced server error (dev panel)', // mocks/helpers.ts
+  'mock-access-token', // mocks/fixtures.ts
+  'mock-dev-panel-root', // mocks/setup.ts
+  'MOCK API', // mocks/DevPanel.tsx (panel title/pill)
+  'setupWorker', // msw/browser entry
+];
+
+function* walk(dir) {
+  for (const entry of readdirSync(dir, { withFileTypes: true })) {
+    const path = join(dir, entry.name);
+    if (entry.isDirectory()) yield* walk(path);
+    else if (/\.(js|css|html)$/.test(entry.name)) yield path;
+  }
+}
+
+let leaked = false;
+let scanned = 0;
+
+for (const file of walk(DIST)) {
+  scanned += 1;
+  const content = readFileSync(file, 'utf8');
+  for (const marker of FORBIDDEN_MARKERS) {
+    if (content.includes(marker)) {
+      leaked = true;
+      console.error(`✗ mock marker ${JSON.stringify(marker)} found in ${file}`);
+    }
+  }
+}
+
+if (leaked) {
+  console.error(
+    '\nMock-mode code leaked into the production bundle. Ensure src/mocks/** is only ' +
+      'imported behind the `import.meta.env.DEV && VITE_ENABLE_MOCKS` guard in src/main.tsx.',
+  );
+  process.exit(1);
+}
+
+console.log(`✓ no mock code in production bundle (${scanned} files scanned)`);
diff --git a/src/main.tsx b/src/main.tsx
index e67f490..82241c5 100644
--- a/src/main.tsx
+++ b/src/main.tsx
@@ -5,19 +5,24 @@ import { createRoot } from 'react-dom/client';
 // under history-API routing. Hash-based routing needs no server config.
 // Revisit if this ever deploys somewhere with a real rewrite rule.
 import { HashRouter } from 'react-router-dom';
-import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import { QueryClientProvider } from '@tanstack/react-query';
+import { queryClient } from './query-client';
 import { useAuthStore } from './store/auth-store';
 import App from './App';
 import './styles/global.css';
 
-const queryClient = new QueryClient({
-  defaultOptions: {
-    queries: {
-      retry: 1,
-      refetchOnWindowFocus: false,
-    },
-  },
-});
+// Mock API for local development (issue #95) — only runs under
+// `npm run dev:mock` (a DEV build with VITE_ENABLE_MOCKS=true). In
+// production builds import.meta.env.DEV is statically false, so this
+// branch is dead code and the mocks chunk is never emitted — CI enforces
+// that with `npm run check:dist` (scripts/check-dist-no-mocks.mjs).
+// Awaited before the first render so the persona session exists when
+// route guards first evaluate (deep links would otherwise bounce to the
+// login screen mid-boot).
+if (import.meta.env.DEV && import.meta.env.VITE_ENABLE_MOCKS === 'true') {
+  const { startMockApi } = await import('./mocks/setup');
+  startMockApi();
+}
 
 // Enable preview session when previewRole query param is set (useful for screenshots & review)
 const urlParams = new URLSearchParams(window.location.search);
diff --git a/src/mocks/DevPanel.module.css b/src/mocks/DevPanel.module.css
new file mode 100644
index 0000000..0f059b0
--- /dev/null
+++ b/src/mocks/DevPanel.module.css
@@ -0,0 +1,159 @@
+.panel {
+  position: fixed;
+  bottom: var(--space-4);
+  left: var(--space-4);
+  z-index: 9999;
+  width: 264px;
+  padding: var(--space-4);
+  background: var(--color-surface);
+  border: 1px solid var(--color-border-strong);
+  border-radius: var(--radius-lg);
+  box-shadow: var(--shadow-lg);
+  font-family: var(--font-sans);
+  font-size: 0.8125rem;
+  color: var(--color-text);
+}
+
+.pill {
+  position: fixed;
+  bottom: var(--space-4);
+  left: var(--space-4);
+  z-index: 9999;
+  padding: var(--space-2) var(--space-3);
+  background: var(--color-accent);
+  color: var(--color-accent-contrast);
+  border: none;
+  border-radius: var(--radius-full);
+  box-shadow: var(--shadow-md);
+  font-family: var(--font-sans);
+  font-size: 0.75rem;
+  font-weight: 600;
+  letter-spacing: 0.04em;
+  cursor: pointer;
+}
+
+.header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: var(--space-2);
+  margin-bottom: var(--space-3);
+}
+
+.title {
+  font-weight: 600;
+}
+
+.warning {
+  margin: 0 0 var(--space-3);
+  padding: var(--space-2);
+  background: var(--color-warning-surface);
+  color: var(--color-text);
+  border-radius: var(--radius-sm);
+  font-size: 0.75rem;
+}
+
+.group {
+  margin-bottom: var(--space-3);
+}
+
+.groupLabel {
+  display: block;
+  margin-bottom: var(--space-1);
+  font-size: 0.6875rem;
+  font-weight: 600;
+  text-transform: uppercase;
+  letter-spacing: 0.06em;
+  color: var(--color-text-muted);
+}
+
+.segmented {
+  display: flex;
+  flex-wrap: wrap;
+  gap: var(--space-1);
+}
+
+.option {
+  flex: 1 1 auto;
+  padding: var(--space-1) var(--space-2);
+  background: var(--color-surface-alt);
+  color: var(--color-text);
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-sm);
+  font-family: inherit;
+  font-size: 0.75rem;
+  cursor: pointer;
+}
+
+.option:hover {
+  background: var(--color-surface-hover);
+}
+
+.optionActive {
+  background: var(--color-accent);
+  border-color: var(--color-accent);
+  color: var(--color-accent-contrast);
+  font-weight: 600;
+}
+
+.latencyRow {
+  display: flex;
+  align-items: center;
+  gap: var(--space-2);
+}
+
+.latencyRow input[type='range'] {
+  flex: 1;
+  accent-color: var(--color-accent);
+}
+
+.latencyValue {
+  min-width: 3.5rem;
+  text-align: right;
+  font-variant-numeric: tabular-nums;
+  color: var(--color-text-muted);
+  font-size: 0.75rem;
+}
+
+.actions {
+  display: flex;
+  gap: var(--space-2);
+}
+
+.action {
+  flex: 1;
+  padding: var(--space-2);
+  background: var(--color-surface-alt);
+  color: var(--color-text);
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-sm);
+  font-family: inherit;
+  font-size: 0.75rem;
+  cursor: pointer;
+}
+
+.action:hover {
+  background: var(--color-surface-hover);
+}
+
+.close {
+  padding: var(--space-1) var(--space-2);
+  background: none;
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-sm);
+  color: var(--color-text-muted);
+  font-family: inherit;
+  font-size: 0.75rem;
+  cursor: pointer;
+}
+
+.close:hover {
+  color: var(--color-text);
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .panel,
+  .pill {
+    transition: none;
+  }
+}
diff --git a/src/mocks/DevPanel.tsx b/src/mocks/DevPanel.tsx
new file mode 100644
index 0000000..bf3f93f
--- /dev/null
+++ b/src/mocks/DevPanel.tsx
@@ -0,0 +1,129 @@
+// Development-only panel for mock mode (issue #95): role switcher, scenario
+// toggles (empty states / forced errors), artificial latency, and fixture
+// reset. Rendered into its own React root from src/mocks/setup.ts — the
+// application tree itself never imports anything under src/mocks/.
+import { useState } from 'react';
+import { queryClient } from '../query-client';
+import { resetDb } from './db';
+import styles from './DevPanel.module.css';
+import { useMockStore, type MockScenario } from './mock-store';
+import { activateMockRole, mockSignOut } from './roles';
+import type { Role } from '../types/models';
+
+const ROLES: Role[] = ['patient', 'doctor', 'facility', 'admin'];
+const SCENARIOS: MockScenario[] = ['normal', 'empty', 'error'];
+
+export function DevPanel() {
+  const [open, setOpen] = useState(true);
+  const scenario = useMockStore((s) => s.scenario);
+  const latencyMs = useMockStore((s) => s.latencyMs);
+  const activeRole = useMockStore((s) => s.activeRole);
+  const setScenario = useMockStore((s) => s.setScenario);
+  const setLatencyMs = useMockStore((s) => s.setLatencyMs);
+
+  if (!open) {
+    return (
+      <button type="button" className={styles.pill} onClick={() => setOpen(true)}>
+        MOCK API
+      </button>
+    );
+  }
+
+  return (
+    <aside className={styles.panel} aria-label="Mock API development panel">
+      <div className={styles.header}>
+        <span className={styles.title}>Mock API</span>
+        <button type="button" className={styles.close} onClick={() => setOpen(false)}>
+          Hide
+        </button>
+      </div>
+
+      <p className={styles.warning}>
+        All data is fake (example.test emails, demo personas). Nothing is persisted —
+        fixtures reset on reload.
+      </p>
+
+      <div className={styles.group}>
+        <span className={styles.groupLabel} id="mock-role-label">
+          Signed in as
+        </span>
+        <div className={styles.segmented} role="group" aria-labelledby="mock-role-label">
+          {ROLES.map((role) => (
+            <button
+              key={role}
+              type="button"
+              className={`${styles.option} ${activeRole === role ? styles.optionActive : ''}`}
+              aria-pressed={activeRole === role}
+              onClick={() => {
+                activateMockRole(role);
+                queryClient.invalidateQueries();
+              }}
+            >
+              {role}
+            </button>
+          ))}
+        </div>
+      </div>
+
+      <div className={styles.group}>
+        <span className={styles.groupLabel} id="mock-scenario-label">
+          Scenario
+        </span>
+        <div className={styles.segmented} role="group" aria-labelledby="mock-scenario-label">
+          {SCENARIOS.map((s) => (
+            <button
+              key={s}
+              type="button"
+              className={`${styles.option} ${scenario === s ? styles.optionActive : ''}`}
+              aria-pressed={scenario === s}
+              onClick={() => {
+                setScenario(s);
+                // Drop cached responses so the new scenario is visible
+                // immediately instead of waiting for staleness.
+                queryClient.invalidateQueries();
+              }}
+            >
+              {s === 'normal' ? 'normal' : s === 'empty' ? 'empty states' : 'errors'}
+            </button>
+          ))}
+        </div>
+      </div>
+
+      <div className={styles.group}>
+        <label className={styles.groupLabel} htmlFor="mock-latency">
+          Response latency
+        </label>
+        <div className={styles.latencyRow}>
+          <input
+            id="mock-latency"
+            type="range"
+            min={0}
+            max={3000}
+            step={250}
+            value={latencyMs}
+            onChange={(e) => setLatencyMs(Number(e.target.value))}
+          />
+          <output className={styles.latencyValue} htmlFor="mock-latency">
+            {latencyMs === 0 ? 'none' : `${latencyMs} ms`}
+          </output>
+        </div>
+      </div>
+
+      <div className={styles.actions}>
+        <button
+          type="button"
+          className={styles.action}
+          onClick={() => {
+            resetDb();
+            queryClient.invalidateQueries();
+          }}
+        >
+          Reset data
+        </button>
+        <button type="button" className={styles.action} onClick={mockSignOut}>
+          Sign out
+        </button>
+      </div>
+    </aside>
+  );
+}
diff --git a/src/mocks/browser.ts b/src/mocks/browser.ts
new file mode 100644
index 0000000..aa4c01a
--- /dev/null
+++ b/src/mocks/browser.ts
@@ -0,0 +1,9 @@
+// MSW service worker for browser mock mode. Only ever loaded from
+// src/mocks/setup.ts, which itself is only dynamically imported by
+// main.tsx when running `npm run dev:mock` (DEV build + VITE_ENABLE_MOCKS).
+// Production builds eliminate that import entirely — verified in CI by
+// `npm run check:dist` (scripts/check-dist-no-mocks.mjs).
+import { setupWorker } from 'msw/browser';
+import { handlers } from './handlers';
+
+export const worker = setupWorker(...handlers);
diff --git a/src/mocks/db.ts b/src/mocks/db.ts
new file mode 100644
index 0000000..194ae27
--- /dev/null
+++ b/src/mocks/db.ts
@@ -0,0 +1,12 @@
+// Mutable in-memory "database" backing the mock API. Handlers mutate this
+// directly (start a visit, add a dependent, fund an intent) so state
+// persists across requests for the lifetime of the dev server — and resets
+// on `Reset fixture data` in the dev panel or on reload. Never imported by
+// application code; only by src/mocks/**.
+import { createSeedDb, type MockDb } from './fixtures';
+
+export let db: MockDb = createSeedDb();
+
+export function resetDb(): void {
+  db = createSeedDb();
+}
diff --git a/src/mocks/fixtures.ts b/src/mocks/fixtures.ts
new file mode 100644
index 0000000..8b0cd99
--- /dev/null
+++ b/src/mocks/fixtures.ts
@@ -0,0 +1,665 @@
+// Seed fixtures for the mock API (issue #95). Everything here is
+// DELIBERATELY FAKE: names use Placeholder/Example/Demo personas and all
+// emails use the RFC 2606 reserved `example.test` domain so no fixture
+// can ever be mistaken for a real person or address. Fixtures mirror the
+// shapes in src/types/models.ts (which mirror docforum-core's schema) —
+// see ARCHITECTURE_ESSENTIALS.md "Known assumptions" for which of those
+// shapes are still assumed contracts.
+import type {
+  Appointment,
+  CareThread,
+  ConsultationAddendum,
+  ConsultationNote,
+  DataExport,
+  Dependent,
+  DoctorPracticeInsights,
+  FacilityInvite,
+  FacilityMember,
+  FacilityWithDistance,
+  FulfillmentQueueItem,
+  HealthEntry,
+  MessageThread,
+  PaymentIntent,
+  RunningDelay,
+  User,
+  WalletLink,
+} from '../types/models';
+
+// --- Personas (one per role the dev panel can switch to) --------------------
+
+export const MOCK_ACCESS_TOKEN = 'mock-access-token';
+
+export const PATIENT_USER: User = {
+  id: 'usr-patient-demo',
+  email: 'pat.placeholder@example.test',
+  role: 'patient',
+  createdAt: '2026-01-05T09:00:00.000Z',
+  updatedAt: '2026-01-05T09:00:00.000Z',
+};
+
+export const DOCTOR_USER: User = {
+  id: 'usr-doctor-demo',
+  email: 'demo.doctor@example.test',
+  role: 'doctor',
+  createdAt: '2026-01-06T09:00:00.000Z',
+  updatedAt: '2026-01-06T09:00:00.000Z',
+};
+
+export const FACILITY_USER: User = {
+  id: 'usr-facility-demo',
+  email: 'frank.facility@example.test',
+  role: 'facility',
+  createdAt: '2026-01-07T09:00:00.000Z',
+  updatedAt: '2026-01-07T09:00:00.000Z',
+};
+
+export const ADMIN_USER: User = {
+  id: 'usr-admin-demo',
+  email: 'al.admin@example.test',
+  role: 'admin',
+  createdAt: '2026-01-08T09:00:00.000Z',
+  updatedAt: '2026-01-08T09:00:00.000Z',
+};
+
+/** Fixed ids used across fixtures so profile-scoped calls line up. */
+export const PATIENT_PROFILE_ID = 'prf-patient-demo';
+export const DEPENDENT_PROFILE_ID = 'prf-dependent-demo';
+export const DOCTOR_PROFILE_ID = 'prf-doctor-demo';
+export const FACILITY_ID = 'fac-demo-pharmacy';
+
+// --- Seed database -----------------------------------------------------------
+
+export interface MockDb {
+  dependents: Dependent[];
+  healthEntries: HealthEntry[];
+  dataExport: DataExport | null;
+  careThreads: CareThread[];
+  appointments: Appointment[];
+  runningDelay: RunningDelay;
+  messageThreads: MessageThread[];
+  consultationNotes: ConsultationNote[];
+  insights: DoctorPracticeInsights;
+  facilities: FacilityWithDistance[];
+  facilityMembers: FacilityMember[];
+  facilityInvites: FacilityInvite[];
+  fulfillmentQueue: FulfillmentQueueItem[];
+  walletLink: WalletLink | null;
+  paymentIntents: PaymentIntent[];
+  consultationAddenda: ConsultationAddendum[]; // flattened, noteId-keyed lookups below
+}
+
+export function createSeedDb(): MockDb {
+  const dependents: Dependent[] = [
+    {
+      id: 'dep-demo-1',
+      guardianProfileId: PATIENT_PROFILE_ID,
+      fullName: 'Tyke Placeholder',
+      dateOfBirth: '2015-04-01',
+      relationship: 'parent',
+      handoverStatus: 'invited',
+      claimEmail: 'tyke.placeholder@example.test',
+      claimInviteExpiresAt: '2026-10-25T09:00:00.000Z',
+      createdAt: '2026-02-01T10:00:00.000Z',
+      updatedAt: '2026-10-10T10:00:00.000Z',
+    },
+    {
+      id: 'dep-demo-2',
+      guardianProfileId: PATIENT_PROFILE_ID,
+      fullName: 'Junior Placeholder',
+      dateOfBirth: '2010-07-15',
+      relationship: 'guardian',
+      handoverStatus: 'not_eligible',
+      createdAt: '2026-03-01T10:00:00.000Z',
+      updatedAt: '2026-03-01T10:00:00.000Z',
+    },
+  ];
+
+  const healthEntries: HealthEntry[] = [
+    {
+      id: 'hev-demo-allergy-1',
+      patientProfileId: PATIENT_PROFILE_ID,
+      section: 'allergies',
+      name: 'Peanuts (fake)',
+      details: 'Demo fixture — severe reaction, carries an auto-injector (not real).',
+      version: 1,
+      updatedAt: '2026-05-01T10:00:00.000Z',
+      createdAt: '2026-05-01T10:00:00.000Z',
+    },
+    {
+      id: 'hev-demo-condition-1',
+      patientProfileId: PATIENT_PROFILE_ID,
+      section: 'conditions',
+      name: 'Sample asthma (fake)',
+      details: 'Demo fixture — mild, exercise-induced.',
+      version: 2,
+      previousValue: 'Sample asthma (fake), mild',
+      updatedAt: '2026-06-01T10:00:00.000Z',
+      createdAt: '2026-06-01T10:00:00.000Z',
+    },
+    {
+      id: 'hev-demo-medication-1',
+      patientProfileId: PATIENT_PROFILE_ID,
+      section: 'medications',
+      name: 'Demo Vitamin D 1000 IU',
+      details: 'Demo fixture — once daily.',
+      version: 1,
+      updatedAt: '2026-07-01T10:00:00.000Z',
+      createdAt: '2026-07-01T10:00:00.000Z',
+    },
+  ];
+
+  const dataExport: DataExport = {
+    id: 'exp-demo-1',
+    patientProfileId: PATIENT_PROFILE_ID,
+    status: 'ready',
+    requestedAt: '2026-10-17T09:00:00.000Z',
+    readyAt: '2026-10-17T09:02:00.000Z',
+    expiresAt: '2026-10-18T09:02:00.000Z',
+    fileSizeBytes: 20480,
+    downloadUrl: null,
+    errorMessage: null,
+  };
+
+  const careThreads: CareThread[] = [
+    {
+      id: 'cth-demo-1',
+      patientProfileId: PATIENT_PROFILE_ID,
+      title: 'Demo cough consult (fake)',
+      doctorName: 'Dr. Ficticia Example',
+      specialty: 'General practice (demo)',
+      startedAt: '2026-10-01T09:00:00.000Z',
+      updatedAt: '2026-10-09T12:00:00.000Z',
+      status: 'active',
+      steps: [
+        {
+          id: 'st-demo-1',
+          stepType: 'appointment',
+          title: 'Appointment booked (demo)',
+          description: 'Demo fixture appointment with Dr. Ficticia Example.',
+          status: 'completed',
+          timestamp: '2026-10-01T09:00:00.000Z',
+        },
+        {
+          id: 'st-demo-2',
+          stepType: 'consultation',
+          title: 'Consultation completed (demo)',
+          description: 'Demo consultation notes recorded.',
+          status: 'completed',
+          timestamp: '2026-10-08T10:00:00.000Z',
+        },
+        {
+          id: 'st-demo-3',
+          stepType: 'order',
+          title: 'Lab order placed (demo)',
+          description: 'Fake full blood count sent to Demo Lab.',
+          status: 'in_progress',
+          timestamp: '2026-10-08T10:15:00.000Z',
+        },
+        {
+          id: 'st-demo-4',
+          stepType: 'payment',
+          title: 'Escrow funded (demo)',
+          description: 'Fake payment intent funded and held in escrow.',
+          status: 'pending',
+        },
+      ],
+    },
+    {
+      id: 'cth-demo-2',
+      patientProfileId: PATIENT_PROFILE_ID,
+      title: 'Demo vaccination visit (fake)',
+      doctorName: 'Dr. Ficticia Example',
+      specialty: 'General practice (demo)',
+      startedAt: '2026-08-10T09:00:00.000Z',
+      updatedAt: '2026-08-10T11:00:00.000Z',
+      status: 'completed',
+      steps: [
+        {
+          id: 'st-demo-5',
+          stepType: 'appointment',
+          title: 'Appointment completed (demo)',
+          description: 'Demo fixture vaccination visit.',
+          status: 'completed',
+          timestamp: '2026-08-10T11:00:00.000Z',
+        },
+      ],
+    },
+  ];
+
+  const appointments: Appointment[] = [
+    {
+      id: 'apt-demo-1',
+      doctorProfileId: DOCTOR_PROFILE_ID,
+      patientProfileId: PATIENT_PROFILE_ID,
+      patientName: 'Pat Placeholder',
+      startsAt: '2026-10-18T08:00:00.000Z',
+      endsAt: '2026-10-18T08:30:00.000Z',
+      status: 'completed',
+      reason: 'Demo follow-up (fake)',
+      checkInAt: '2026-10-18T07:55:00.000Z',
+      startedAt: '2026-10-18T08:05:00.000Z',
+      completedAt: '2026-10-18T08:28:00.000Z',
+    },
+    {
+      id: 'apt-demo-2',
+      doctorProfileId: DOCTOR_PROFILE_ID,
+      patientProfileId: 'prf-patient-2',
+      patientName: 'Sam Example',
+      startsAt: '2026-10-18T09:00:00.000Z',
+      endsAt: '2026-10-18T09:30:00.000Z',
+      status: 'in_progress',
+      reason: 'Demo chest pain assessment (fake)',
+      checkInAt: '2026-10-18T08:52:00.000Z',
+      startedAt: '2026-10-18T09:07:00.000Z',
+      completedAt: null,
+    },
+    {
+      id: 'apt-demo-3',
+      doctorProfileId: DOCTOR_PROFILE_ID,
+      patientProfileId: 'prf-patient-3',
+      patientName: 'Quinn Example',
+      startsAt: '2026-10-18T09:30:00.000Z',
+      endsAt: '2026-10-18T10:00:00.000Z',
+      status: 'checked_in',
+      reason: 'Demo prescription review (fake)',
+      checkInAt: '2026-10-18T09:20:00.000Z',
+      startedAt: null,
+      completedAt: null,
+    },
+    {
+      id: 'apt-demo-4',
+      doctorProfileId: DOCTOR_PROFILE_ID,
+      patientProfileId: 'prf-patient-4',
+      patientName: 'Robin Sample',
+      startsAt: '2026-10-18T10:00:00.000Z',
+      endsAt: '2026-10-18T10:30:00.000Z',
+      status: 'scheduled',
+      reason: 'Demo new concern (fake)',
+      checkInAt: null,
+      startedAt: null,
+      completedAt: null,
+    },
+    {
+      id: 'apt-demo-5',
+      doctorProfileId: DOCTOR_PROFILE_ID,
+      patientProfileId: 'prf-patient-5',
+      patientName: 'Morgan Testdata',
+      startsAt: '2026-10-18T10:30:00.000Z',
+      endsAt: '2026-10-18T11:00:00.000Z',
+      status: 'no_show',
+      reason: 'Demo no-show (fake)',
+      checkInAt: null,
+      startedAt: null,
+      completedAt: null,
+    },
+  ];
+
+  const runningDelay: RunningDelay = {
+    computedDelayMin: 12,
+    manualOverrideMin: null,
+    effectiveDelayMin: 12,
+  };
+
+  const messageThreads: MessageThread[] = [
+    {
+      id: 'mth-demo-1',
+      patientProfileId: PATIENT_PROFILE_ID,
+      patientName: 'Pat Placeholder',
+      lastMessageAt: '2026-10-18T07:10:00.000Z',
+      unreadCount: 3,
+      lastPreview: 'Demo message (fake): my cough got worse overnight…',
+      waitingMinutes: 185,
+      closingSoon: true,
+    },
+    {
+      id: 'mth-demo-2',
+      patientProfileId: 'prf-patient-2',
+      patientName: 'Sam Example',
+      lastMessageAt: '2026-10-18T08:45:00.000Z',
+      unreadCount: 1,
+      lastPreview: 'Demo message (fake): when should I take the new tablets?',
+      waitingMinutes: 90,
+      closingSoon: false,
+    },
+    {
+      id: 'mth-demo-3',
+      patientProfileId: 'prf-patient-3',
+      patientName: 'Quinn Example',
+      lastMessageAt: '2026-10-17T16:20:00.000Z',
+      unreadCount: 0,
+      lastPreview: 'Demo message (fake): thanks doctor!',
+      waitingMinutes: null,
+      closingSoon: false,
+    },
+    {
+      id: 'mth-demo-4',
+      patientProfileId: 'prf-patient-6',
+      patientName: 'Casey Fixture',
+      lastMessageAt: '2026-10-18T08:00:00.000Z',
+      unreadCount: 2,
+      lastPreview: 'Demo message (fake): pharmacy says my order is not ready…',
+      waitingMinutes: 120,
+      closingSoon: true,
+    },
+  ];
+
+  const consultationAddenda: ConsultationAddendum[] = [
+    {
+      id: 'cad-demo-1',
+      noteId: 'not-demo-signed',
+      content: 'Demo addendum (fake): patient called to confirm dosage.',
+      createdAt: '2026-10-16T12:00:00.000Z',
+    },
+  ];
+
+  const consultationNotes: ConsultationNote[] = [
+    {
+      id: 'not-demo-unsigned',
+      appointmentId: 'apt-demo-2',
+      content:
+        'Demo consultation note (fake). Patient reports mild symptoms. Plan: rest, fluids, review in one week. No real medical data lives in this fixture.',
+      signedAt: null,
+      signedBy: null,
+      autoSignOffAt: '2026-10-19T09:00:00.000Z',
+      addenda: [],
+    },
+    {
+      id: 'not-demo-signed',
+      appointmentId: 'apt-demo-1',
+      content: 'Demo consultation note (fake), already signed off.',
+      signedAt: '2026-10-18T08:35:00.000Z',
+      signedBy: 'Dr. Demo Doctor (fake)',
+      autoSignOffAt: null,
+      addenda: consultationAddenda.filter((a) => a.noteId === 'not-demo-signed'),
+    },
+  ];
+
+  const insights: DoctorPracticeInsights = {
+    doctorProfileId: DOCTOR_PROFILE_ID,
+    range: { preset: '30d', startDate: '2026-09-18', endDate: '2026-10-18' },
+    generatedAt: '2026-10-18T06:00:00.000Z',
+    utilisation: {
+      weeks: [
+        {
+          weekLabel: 'Sep 21',
+          startDate: '2026-09-21',
+          endDate: '2026-09-27',
+          offeredSlots: 40,
+          bookedSlots: 31,
+          completedSlots: 28,
+          utilisationRate: 77.5,
+        },
+        {
+          weekLabel: 'Sep 28',
+          startDate: '2026-09-28',
+          endDate: '2026-10-04',
+          offeredSlots: 40,
+          bookedSlots: 34,
+          completedSlots: 30,
+          utilisationRate: 85,
+        },
+        {
+          weekLabel: 'Oct 5',
+          startDate: '2026-10-05',
+          endDate: '2026-10-11',
+          offeredSlots: 40,
+          bookedSlots: 26,
+          completedSlots: 24,
+          utilisationRate: 65,
+        },
+        {
+          weekLabel: 'Oct 12',
+          startDate: '2026-10-12',
+          endDate: '2026-10-18',
+          offeredSlots: 40,
+          bookedSlots: 33,
+          completedSlots: 21,
+          utilisationRate: 82.5,
+        },
+      ],
+      overallOfferedSlots: 160,
+      overallBookedSlots: 124,
+      overallUtilisationRate: 77.5,
+      sampleSizeWarning: false,
+    },
+    noShows: {
+      totalScheduled: 124,
+      completedVisits: 103,
+      noShows: 9,
+      lateCancellations: 5,
+      onTimeCancellations: 7,
+      noShowRate: 7.3,
+      lateCancelRate: 4,
+      sampleSizeWarning: false,
+    },
+    referrals: {
+      totalSent: 14,
+      totalAccepted: 10,
+      totalPending: 4,
+      averageAcceptanceHours: 30.5,
+      medianAcceptanceHours: 22,
+      breakdownUnder24h: 6,
+      breakdown24to48h: 3,
+      breakdownOver48h: 1,
+      sampleSizeWarning: false,
+    },
+    messages: {
+      totalThreads: 38,
+      averageFirstResponseMinutes: 74,
+      medianFirstResponseMinutes: 41,
+      respondedWithin2hCount: 24,
+      respondedWithin24hCount: 35,
+      rateWithin2h: 63.2,
+      sampleSizeWarning: false,
+    },
+  };
+
+  const facilities: FacilityWithDistance[] = [
+    {
+      id: FACILITY_ID,
+      userId: 'usr-facility-demo',
+      name: 'Demo Pharmacy (fake)',
+      type: 'pharmacy',
+      location: {
+        address: '1 Fixture Lane',
+        city: 'Sampleton',
+        latitude: 6.5244,
+        longitude: 3.3792,
+      },
+      distanceKm: null,
+      isOpen: true,
+      phone: '+000-000-0001 (fake)',
+      rating: 4.6,
+    },
+    {
+      id: 'fac-demo-lab',
+      userId: 'usr-facility-lab',
+      name: 'Demo Lab (fake)',
+      type: 'lab',
+      location: {
+        address: '2 Fixture Lane',
+        city: 'Sampleton',
+        latitude: 6.5312,
+        longitude: 3.3915,
+      },
+      distanceKm: null,
+      isOpen: true,
+      phone: '+000-000-0002 (fake)',
+      rating: 4.2,
+    },
+    {
+      id: 'fac-demo-pharmacy-2',
+      userId: 'usr-facility-pharmacy-2',
+      name: 'Example Chemist (fake)',
+      type: 'pharmacy',
+      location: {
+        address: '3 Example Street',
+        city: 'Mockford',
+        latitude: 6.6,
+        longitude: 3.45,
+      },
+      distanceKm: null,
+      isOpen: false,
+      phone: '+000-000-0003 (fake)',
+      rating: 3.9,
+    },
+  ];
+
+  const facilityMembers: FacilityMember[] = [
+    {
+      id: 'fmb-demo-owner',
+      facilityId: FACILITY_ID,
+      userId: 'usr-facility-demo',
+      fullName: 'Frank Facility (fake)',
+      email: 'frank.facility@example.test',
+      role: 'owner',
+      joinedAt: '2026-01-10T09:00:00.000Z',
+      isCurrentUser: true,
+    },
+    {
+      id: 'fmb-demo-staff',
+      facilityId: FACILITY_ID,
+      userId: 'usr-facility-staff',
+      fullName: 'Mo Example (fake)',
+      email: 'mo.example@example.test',
+      role: 'staff',
+      joinedAt: '2026-02-14T09:00:00.000Z',
+      isCurrentUser: false,
+    },
+  ];
+
+  const facilityInvites: FacilityInvite[] = [
+    {
+      id: 'inv-demo-1',
+      facilityId: FACILITY_ID,
+      email: 'new.staff@example.test',
+      role: 'staff',
+      invitedBy: 'usr-facility-demo',
+      invitedAt: '2026-10-15T09:00:00.000Z',
+      expiresAt: '2026-10-22T09:00:00.000Z',
+      status: 'pending',
+    },
+  ];
+
+  const fulfillmentQueue: FulfillmentQueueItem[] = [
+    {
+      id: 'fuq-demo-1',
+      facilityId: FACILITY_ID,
+      orderId: 'ord-demo-rx-1',
+      orderType: 'prescription',
+      patientName: 'Pat Placeholder',
+      patientProfileId: PATIENT_PROFILE_ID,
+      itemName: 'Demo Amoxicillin 500mg (fake)',
+      instructions: 'Demo instructions (fake): one capsule three times daily for five days.',
+      status: 'pending',
+      receivedAt: '2026-10-18T07:30:00.000Z',
+      attribution: null,
+    },
+    {
+      id: 'fuq-demo-2',
+      facilityId: FACILITY_ID,
+      orderId: 'ord-demo-lab-1',
+      orderType: 'lab',
+      patientName: 'Sam Example',
+      patientProfileId: 'prf-patient-2',
+      itemName: 'Demo blood panel (fake)',
+      instructions: 'Demo instructions (fake): fasting sample required.',
+      status: 'pending',
+      receivedAt: '2026-10-18T08:05:00.000Z',
+      attribution: null,
+    },
+    {
+      id: 'fuq-demo-3',
+      facilityId: FACILITY_ID,
+      orderId: 'ord-demo-rx-2',
+      orderType: 'prescription',
+      patientName: 'Quinn Example',
+      patientProfileId: 'prf-patient-3',
+      itemName: 'Demo Metformin 850mg (fake)',
+      instructions: null,
+      status: 'fulfilled',
+      receivedAt: '2026-10-17T14:00:00.000Z',
+      attribution: {
+        action: 'dispensed',
+        performedByUserId: 'usr-facility-staff',
+        performedByName: 'Mo Example (fake)',
+        performedByEmail: 'mo.example@example.test',
+        performedByRole: 'staff',
+        timestamp: '2026-10-17T14:40:00.000Z',
+        notes: 'Demo attribution (fake).',
+      },
+    },
+  ];
+
+  const walletLink: WalletLink = {
+    id: 'wln-demo-1',
+    facilityId: FACILITY_ID,
+    stellarPublicKey: 'GDEMOFAKEKEY000000000000000000000000000000000000000000000000',
+    createdAt: '2026-09-20T09:00:00.000Z',
+    updatedAt: '2026-09-20T09:00:00.000Z',
+  };
+
+  const paymentIntents: PaymentIntent[] = [
+    {
+      id: 'pin-demo-1',
+      orderType: 'prescription',
+      orderId: 'ord-demo-rx-1',
+      status: 'escrowed',
+      patientProfileId: PATIENT_PROFILE_ID,
+      facilityId: FACILITY_ID,
+      amountStroops: '500000000',
+      escrowId: 'esc-demo-1 (fake)',
+      stellarTxHash: 'txdemo000000000000000000000000000000000000000000000000000000000001',
+      sorobanContractId: 'CD demo contract (fake)',
+      createdAt: '2026-10-17T10:00:00.000Z',
+      updatedAt: '2026-10-17T10:05:00.000Z',
+    },
+    {
+      id: 'pin-demo-2',
+      orderType: 'lab_order',
+      orderId: 'ord-demo-lab-1',
+      status: 'created',
+      patientProfileId: 'prf-patient-2',
+      facilityId: FACILITY_ID,
+      amountStroops: '250000000',
+      escrowId: null,
+      stellarTxHash: null,
+      sorobanContractId: null,
+      createdAt: '2026-10-18T08:10:00.000Z',
+      updatedAt: '2026-10-18T08:10:00.000Z',
+    },
+    {
+      id: 'pin-demo-3',
+      orderType: 'prescription',
+      orderId: 'ord-demo-rx-2',
+      status: 'released',
+      patientProfileId: 'prf-patient-3',
+      facilityId: FACILITY_ID,
+      amountStroops: '750000000',
+      escrowId: 'esc-demo-3 (fake)',
+      stellarTxHash: 'txdemo000000000000000000000000000000000000000000000000000000000003',
+      sorobanContractId: 'CD demo contract (fake)',
+      createdAt: '2026-10-15T10:00:00.000Z',
+      updatedAt: '2026-10-16T09:00:00.000Z',
+    },
+  ];
+
+  return {
+    dependents,
+    healthEntries,
+    dataExport,
+    careThreads,
+    appointments,
+    runningDelay,
+    messageThreads,
+    consultationNotes,
+    insights,
+    facilities,
+    facilityMembers,
+    facilityInvites,
+    fulfillmentQueue,
+    walletLink,
+    paymentIntents,
+    consultationAddenda,
+  };
+}
diff --git a/src/mocks/handlers.test.ts b/src/mocks/handlers.test.ts
new file mode 100644
index 0000000..53932ad
--- /dev/null
+++ b/src/mocks/handlers.test.ts
@@ -0,0 +1,414 @@
+// Tests for the mock API (issue #95). Each test drives the app's REAL
+// service layer (src/services/*) through apiFetch → fetch → MSW, proving
+// the handlers cover every endpoint the application uses and honour the
+// dev panel's scenario/latency switches. Runs in the node environment so
+// MSW's fetch interceptor wraps Node's global fetch.
+// @vitest-environment node
+import { afterAll, beforeAll, beforeEach, describe, expect, it } from 'vitest';
+import { setupServer } from 'msw/node';
+import { handlers } from './handlers';
+import { resetDb } from './db';
+import { useMockStore } from './mock-store';
+import { DOCTOR_USER, MOCK_ACCESS_TOKEN } from './fixtures';
+import { ApiError } from '../services/api-client';
+import * as authService from '../services/auth-service';
+import * as accountService from '../services/account-service';
+import * as careThreadService from '../services/care-thread-service';
+import * as consultationService from '../services/consultation-service';
+import * as dependentsService from '../services/dependents-service';
+import * as facilityService from '../services/facility-service';
+import * as facilityTeamService from '../services/facility-team-service';
+import * as healthService from '../services/health-profile-service';
+import * as insightsService from '../services/insights-service';
+import * as messagingService from '../services/messaging-service';
+import * as paymentsService from '../services/payments-service';
+import * as queueService from '../services/queue-service';
+import { FACILITY_ID, PATIENT_PROFILE_ID } from './fixtures';
+
+const server = setupServer(...handlers);
+
+beforeAll(() => server.listen({ onUnhandledRequest: 'error' }));
+afterAll(() => server.close());
+beforeEach(() => {
+  resetDb();
+  useMockStore.setState({ scenario: 'normal', latencyMs: 0, activeRole: 'patient' });
+});
+
+describe('auth', () => {
+  it('logs in a seeded persona by email', async () => {
+    const session = await authService.login({
+      email: DOCTOR_USER.email,
+      password: 'whatever',
+    });
+    expect(session.user.role).toBe('doctor');
+    expect(session.accessToken).toBe(MOCK_ACCESS_TOKEN);
+  });
+
+  it('logs an unknown email in as the dev panel active role', async () => {
+    useMockStore.setState({ activeRole: 'doctor' });
+    const session = await authService.login({
+      email: 'someone@example.test',
+      password: 'whatever',
+    });
+    expect(session.user.role).toBe('doctor');
+    expect(session.user.email).toBe('someone@example.test');
+  });
+
+  it('rejects missing credentials with a 400 envelope', async () => {
+    await expect(
+      authService.login({ email: '', password: '' }),
+    ).rejects.toMatchObject({ status: 400 });
+  });
+
+  it('signs up a patient and logs out', async () => {
+    const session = await authService.signup({
+      role: 'patient',
+      email: 'new.person@example.test',
+      password: 'x',
+      fullName: 'New Person (fake)',
+    });
+    expect(session.user.role).toBe('patient');
+    // apiFetch returns the parsed JSON body — `null` for void endpoints.
+    await expect(authService.logout(session.accessToken)).resolves.toBeNull();
+  });
+
+  it('claims an account', async () => {
+    await expect(
+      dependentsService.claimAccount({ token: 't', email: 'a@example.test', password: 'x' }),
+    ).resolves.toBeNull();
+  });
+});
+
+describe('dependents', () => {
+  it('lists seeded dependents and adds a new one', async () => {
+    const seeded = await dependentsService.listDependents(MOCK_ACCESS_TOKEN);
+    expect(seeded).toHaveLength(2);
+
+    await dependentsService.addDependent(
+      { fullName: 'New Fake Dependent', dateOfBirth: '2012-01-01', relationship: 'parent' },
+      MOCK_ACCESS_TOKEN,
+    );
+    const after = await dependentsService.listDependents(MOCK_ACCESS_TOKEN);
+    expect(after).toHaveLength(3);
+  });
+
+  it('updates a dependent and manages handover invites', async () => {
+    const updated = await dependentsService.updateDependent(
+      'dep-demo-2',
+      { fullName: 'Renamed Placeholder', dateOfBirth: '2010-07-15', relationship: 'guardian' },
+      MOCK_ACCESS_TOKEN,
+    );
+    expect(updated.fullName).toBe('Renamed Placeholder');
+
+    const invited = await dependentsService.sendHandoverInvite(
+      'dep-demo-2',
+      'junior.claim@example.test',
+      MOCK_ACCESS_TOKEN,
+    );
+    expect(invited.handoverStatus).toBe('invited');
+    expect(invited.claimEmail).toBe('junior.claim@example.test');
+
+    const resent = await dependentsService.resendHandoverInvite('dep-demo-2', MOCK_ACCESS_TOKEN);
+    expect(resent.claimInviteExpiresAt).toBeTruthy();
+  });
+
+  it('404s on an unknown dependent', async () => {
+    await expect(
+      dependentsService.updateDependent(
+        'nope',
+        { fullName: 'x', dateOfBirth: '2000-01-01', relationship: 'parent' },
+        MOCK_ACCESS_TOKEN,
+      ),
+    ).rejects.toMatchObject({ status: 404 });
+  });
+});
+
+describe('health profile', () => {
+  it('lists, adds, versions and deletes entries per section', async () => {
+    const allergies = await healthService.listHealthEntries(
+      PATIENT_PROFILE_ID,
+      'allergies',
+      MOCK_ACCESS_TOKEN,
+    );
+    expect(allergies).toHaveLength(1);
+
+    const added = await healthService.addHealthEntry(
+      PATIENT_PROFILE_ID,
+      { section: 'allergies', name: 'Dust (fake)' },
+      MOCK_ACCESS_TOKEN,
+    );
+    expect(added.version).toBe(1);
+
+    const patched = await healthService.updateHealthEntry(
+      PATIENT_PROFILE_ID,
+      added.id,
+      { name: 'Dust mites (fake)' },
+      MOCK_ACCESS_TOKEN,
+    );
+    expect(patched.version).toBe(2);
+    expect(patched.previousValue).toBe('Dust (fake)');
+
+    await healthService.removeHealthEntry(PATIENT_PROFILE_ID, added.id, MOCK_ACCESS_TOKEN);
+    const after = await healthService.listHealthEntries(
+      PATIENT_PROFILE_ID,
+      'allergies',
+      MOCK_ACCESS_TOKEN,
+    );
+    expect(after).toHaveLength(1);
+  });
+});
+
+describe('account', () => {
+  it('requests, reads and downloads a data export', async () => {
+    const requested = await accountService.requestDataExport('pw', MOCK_ACCESS_TOKEN);
+    expect(requested.status).toBe('ready');
+
+    const current = await accountService.getDataExportStatus(MOCK_ACCESS_TOKEN);
+    expect(current?.id).toBe(requested.id);
+
+    const blob = await accountService.downloadDataExport(requested.id, MOCK_ACCESS_TOKEN);
+    const text = await blob.text();
+    expect(text).toContain('FAKE DATA EXPORT');
+  });
+
+  it('deletes the account with a confirmation message', async () => {
+    const response = await accountService.deleteAccount('pw', 'DELETE', MOCK_ACCESS_TOKEN);
+    expect(response.success).toBe(true);
+    expect(response.message).toContain('Mock API');
+  });
+});
+
+describe('care threads', () => {
+  it('lists threads for a profile and fetches one by id', async () => {
+    const threads = await careThreadService.getCareThreads(PATIENT_PROFILE_ID, MOCK_ACCESS_TOKEN);
+    expect(threads.length).toBeGreaterThan(0);
+
+    const thread = await careThreadService.getCareThreadById(threads[0].id, MOCK_ACCESS_TOKEN);
+    expect(thread.steps.length).toBeGreaterThan(0);
+  });
+});
+
+describe('consultation notes', () => {
+  it('fetches by appointment, signs off, and appends addenda', async () => {
+    const note = await consultationService.getConsultationNote('apt-demo-2', MOCK_ACCESS_TOKEN);
+    expect(note.signedAt).toBeNull();
+
+    const signed = await consultationService.signOffNote(note.id, MOCK_ACCESS_TOKEN);
+    expect(signed.signedAt).toBeTruthy();
+
+    const addendum = await consultationService.addAddendum(
+      note.id,
+      { content: 'Demo addendum (fake).' },
+      MOCK_ACCESS_TOKEN,
+    );
+    expect(addendum.noteId).toBe(note.id);
+  });
+
+  it('409s when signing off twice', async () => {
+    await expect(
+      consultationService.signOffNote('not-demo-signed', MOCK_ACCESS_TOKEN),
+    ).rejects.toMatchObject({ status: 409 });
+  });
+});
+
+describe('doctor queue', () => {
+  it('lists appointments, derives the queue, and starts/complete visits', async () => {
+    const appointments = await queueService.listTodayAppointments(MOCK_ACCESS_TOKEN);
+    expect(appointments.length).toBe(5);
+
+    const queue = await queueService.listQueue(MOCK_ACCESS_TOKEN);
+    expect(queue[0].queuePosition).toBe(1);
+
+    const started = await queueService.startVisit('apt-demo-3', MOCK_ACCESS_TOKEN);
+    expect(started.status).toBe('in_progress');
+
+    const completed = await queueService.completeVisit('apt-demo-3', MOCK_ACCESS_TOKEN);
+    expect(completed.status).toBe('completed');
+
+    await expect(queueService.completeVisit('apt-demo-4', MOCK_ACCESS_TOKEN)).rejects.toMatchObject({
+      status: 409,
+    });
+  });
+
+  it('applies the running-delay override', async () => {
+    const delay = await queueService.getRunningDelay(MOCK_ACCESS_TOKEN);
+    expect(delay.effectiveDelayMin).toBe(delay.computedDelayMin);
+
+    const overridden = await queueService.updateRunningDelay(
+      { manualOverrideMin: 25 },
+      MOCK_ACCESS_TOKEN,
+    );
+    expect(overridden.effectiveDelayMin).toBe(25);
+
+    const cleared = await queueService.updateRunningDelay(
+      { manualOverrideMin: null },
+      MOCK_ACCESS_TOKEN,
+    );
+    expect(cleared.manualOverrideMin).toBeNull();
+    expect(cleared.effectiveDelayMin).toBe(cleared.computedDelayMin);
+  });
+});
+
+describe('messaging', () => {
+  it('filters threads and marks them read', async () => {
+    const all = await messagingService.listThreads({}, MOCK_ACCESS_TOKEN);
+    expect(all.threads.length).toBe(4);
+    expect(messagingService.totalUnread(all.threads)).toBe(6);
+
+    const unread = await messagingService.listThreads({ filter: 'unread' }, MOCK_ACCESS_TOKEN);
+    expect(unread.threads.every((t) => t.unreadCount > 0)).toBe(true);
+
+    await messagingService.markThreadRead('mth-demo-1', MOCK_ACCESS_TOKEN);
+    const after = await messagingService.listThreads({}, MOCK_ACCESS_TOKEN);
+    expect(after.threads.find((t) => t.id === 'mth-demo-1')?.unreadCount).toBe(0);
+  });
+});
+
+describe('insights', () => {
+  it('returns seeded insights and echoes the requested range', async () => {
+    const insights = await insightsService.getDoctorPracticeInsights(MOCK_ACCESS_TOKEN);
+    expect(insights.utilisation.weeks.length).toBeGreaterThan(0);
+
+    const ranged = await insightsService.getDoctorPracticeInsights(MOCK_ACCESS_TOKEN, {
+      preset: '7d',
+      startDate: '2026-10-11',
+      endDate: '2026-10-18',
+    });
+    expect(ranged.range.preset).toBe('7d');
+    expect(ranged.range.startDate).toBe('2026-10-11');
+  });
+});
+
+describe('facility finder', () => {
+  it('filters by type and sorts by distance when coordinates are given', async () => {
+    const all = await facilityService.getFacilities({}, MOCK_ACCESS_TOKEN);
+    expect(all.length).toBe(3);
+
+    const labs = await facilityService.getFacilities({ type: 'lab' }, MOCK_ACCESS_TOKEN);
+    expect(labs.every((f) => f.type === 'lab')).toBe(true);
+
+    const nearby = await facilityService.getFacilities(
+      { lat: 6.5244, lng: 3.3792 },
+      MOCK_ACCESS_TOKEN,
+    );
+    expect(nearby[0].id).toBe('fac-demo-pharmacy');
+    expect(nearby[0].distanceKm).toBeLessThan(0.1);
+  });
+});
+
+describe('facility team', () => {
+  it('lists members and invites, and sends an invite', async () => {
+    const members = await facilityTeamService.listFacilityMembers(FACILITY_ID, MOCK_ACCESS_TOKEN);
+    expect(members).toHaveLength(2);
+
+    const invites = await facilityTeamService.listFacilityInvites(FACILITY_ID, MOCK_ACCESS_TOKEN);
+    expect(invites).toHaveLength(1);
+
+    const invite = await facilityTeamService.inviteFacilityMember(
+      FACILITY_ID,
+      { email: 'more.staff@example.test', role: 'staff' },
+      MOCK_ACCESS_TOKEN,
+    );
+    expect(invite.status).toBe('pending');
+
+    await facilityTeamService.resendFacilityInvite(FACILITY_ID, invite.id, MOCK_ACCESS_TOKEN);
+    await facilityTeamService.revokeFacilityInvite(FACILITY_ID, invite.id, MOCK_ACCESS_TOKEN);
+    const after = await facilityTeamService.listFacilityInvites(FACILITY_ID, MOCK_ACCESS_TOKEN);
+    expect(after).toHaveLength(1);
+  });
+
+  it('refuses to remove the last owner', async () => {
+    await expect(
+      facilityTeamService.removeFacilityMember(FACILITY_ID, 'fmb-demo-owner', MOCK_ACCESS_TOKEN),
+    ).rejects.toMatchObject({ status: 409 });
+
+    const removed = await facilityTeamService.removeFacilityMember(
+      FACILITY_ID,
+      'fmb-demo-staff',
+      MOCK_ACCESS_TOKEN,
+    );
+    expect(removed.sessionsRevoked).toBe(true);
+  });
+
+  it('fulfills queue items with attribution', async () => {
+    const queue = await facilityTeamService.getFulfillmentQueue(FACILITY_ID, MOCK_ACCESS_TOKEN);
+    expect(queue).toHaveLength(3);
+
+    const updated = await facilityTeamService.updateFulfillmentItem(
+      FACILITY_ID,
+      'fuq-demo-1',
+      'fulfilled',
+      MOCK_ACCESS_TOKEN,
+      'Demo note (fake)',
+    );
+    expect(updated.status).toBe('fulfilled');
+    expect(updated.attribution?.performedByRole).toBe('owner');
+    expect(updated.attribution?.action).toBe('dispensed');
+  });
+});
+
+describe('payments', () => {
+  it('links a wallet and drives an intent through fund → release', async () => {
+    const wallet = await paymentsService.getOwnWalletLink(MOCK_ACCESS_TOKEN);
+    expect(wallet?.stellarPublicKey).toContain('GDEMOFAKE');
+
+    const relinked = await paymentsService.linkWallet('GNEWFAKEKEY', MOCK_ACCESS_TOKEN);
+    expect(relinked.stellarPublicKey).toBe('GNEWFAKEKEY');
+
+    const created = await paymentsService.createPaymentIntent(
+      {
+        orderType: 'prescription',
+        orderId: 'ord-mock-new',
+        patientProfileId: PATIENT_PROFILE_ID,
+        facilityId: FACILITY_ID,
+        amountStroops: '123456789',
+      },
+      MOCK_ACCESS_TOKEN,
+    );
+    expect(created.status).toBe('created');
+    expect(created.amountStroops).toBe('123456789'); // BigInt-as-string preserved
+
+    const funded = await paymentsService.fundPaymentIntent(created.id, MOCK_ACCESS_TOKEN);
+    expect(funded.status).toBe('escrowed');
+
+    const released = await paymentsService.releasePaymentIntent(created.id, MOCK_ACCESS_TOKEN);
+    expect(released.status).toBe('released');
+
+    await expect(
+      paymentsService.refundPaymentIntent(created.id, MOCK_ACCESS_TOKEN),
+    ).rejects.toMatchObject({ status: 409 });
+  });
+});
+
+describe('dev panel scenarios', () => {
+  it('forces 500s in the "error" scenario', async () => {
+    useMockStore.setState({ scenario: 'error' });
+    const error = await dependentsService
+      .listDependents(MOCK_ACCESS_TOKEN)
+      .then(() => null)
+      .catch((e: unknown) => e);
+    expect(error).toBeInstanceOf(ApiError);
+    expect((error as ApiError).status).toBe(500);
+    expect((error as ApiError).message).toContain('forced server error');
+  });
+
+  it('returns empty lists and null singletons in the "empty" scenario', async () => {
+    useMockStore.setState({ scenario: 'empty' });
+    await expect(dependentsService.listDependents(MOCK_ACCESS_TOKEN)).resolves.toEqual([]);
+    await expect(
+      queueService.listTodayAppointments(MOCK_ACCESS_TOKEN),
+    ).resolves.toEqual([]);
+    await expect(
+      facilityTeamService.getFulfillmentQueue(FACILITY_ID, MOCK_ACCESS_TOKEN),
+    ).resolves.toEqual([]);
+    await expect(accountService.getDataExportStatus(MOCK_ACCESS_TOKEN)).resolves.toBeNull();
+    await expect(paymentsService.getOwnWalletLink(MOCK_ACCESS_TOKEN)).resolves.toBeNull();
+  });
+
+  it('delays responses by the configured latency', async () => {
+    useMockStore.setState({ latencyMs: 200 });
+    const started = Date.now();
+    await dependentsService.listDependents(MOCK_ACCESS_TOKEN);
+    expect(Date.now() - started).toBeGreaterThanOrEqual(180);
+  });
+});
diff --git a/src/mocks/handlers.ts b/src/mocks/handlers.ts
new file mode 100644
index 0000000..b1bdb11
--- /dev/null
+++ b/src/mocks/handlers.ts
@@ -0,0 +1,29 @@
+// All mock handlers, composed. Order matters only where paths could
+// overlap — specific (`/patients/me/…`) before generic (`/patients/:id/…`).
+import { accountHandlers } from './handlers/account';
+import { authHandlers } from './handlers/auth';
+import { careThreadHandlers } from './handlers/care-thread';
+import { consultationHandlers } from './handlers/consultation';
+import { dependentHandlers } from './handlers/dependents';
+import { facilityTeamHandlers } from './handlers/facility-team';
+import { facilityHandlers } from './handlers/facility';
+import { healthProfileHandlers } from './handlers/health-profile';
+import { insightsHandlers } from './handlers/insights';
+import { messagingHandlers } from './handlers/messaging';
+import { paymentsHandlers } from './handlers/payments';
+import { queueHandlers } from './handlers/queue';
+
+export const handlers = [
+  ...authHandlers,
+  ...accountHandlers,
+  ...dependentHandlers,
+  ...healthProfileHandlers,
+  ...careThreadHandlers,
+  ...consultationHandlers,
+  ...queueHandlers,
+  ...messagingHandlers,
+  ...insightsHandlers,
+  ...facilityHandlers,
+  ...facilityTeamHandlers,
+  ...paymentsHandlers,
+];
diff --git a/src/mocks/handlers/account.ts b/src/mocks/handlers/account.ts
new file mode 100644
index 0000000..3f4aab6
--- /dev/null
+++ b/src/mocks/handlers/account.ts
@@ -0,0 +1,69 @@
+// Account endpoints: data export lifecycle and account deletion.
+import { http, HttpResponse } from 'msw';
+import { db } from '../db';
+import { respond } from '../helpers';
+import { PATIENT_PROFILE_ID } from '../fixtures';
+import { useMockStore } from '../mock-store';
+import type { DataExport } from '../../types/models';
+
+export const accountHandlers = [
+  http.post(
+    '*/account/data-export',
+    respond('json', () => {
+      const now = new Date();
+      const ready: DataExport = {
+        id: `exp-mock-${Date.now()}`,
+        patientProfileId: PATIENT_PROFILE_ID,
+        status: 'ready',
+        requestedAt: now.toISOString(),
+        readyAt: now.toISOString(),
+        expiresAt: new Date(now.getTime() + 24 * 60 * 60 * 1000).toISOString(),
+        fileSizeBytes: 20480,
+        downloadUrl: null,
+        errorMessage: null,
+      };
+      db.dataExport = ready;
+      return ready;
+    }),
+  ),
+
+  http.get('*/account/data-export', respond('nullable', () => db.dataExport)),
+
+  http.get(
+    '*/account/data-export/:id/download',
+    async ({ params }) => {
+      const { scenario, latencyMs } = useMockStore.getState();
+      if (latencyMs > 0) await new Promise((r) => setTimeout(r, latencyMs));
+      if (scenario === 'error') {
+        return HttpResponse.json(
+          { message: 'Mock scenario: forced server error (dev panel)' },
+          { status: 500 },
+        );
+      }
+      const payload = {
+        note: 'FAKE DATA EXPORT — generated by docforum-web mock API. Contains no real records.',
+        exportId: String(params.id),
+        generatedAt: new Date().toISOString(),
+        profile: { fullName: 'Pat Placeholder (fake)', dateOfBirth: '1990-01-01' },
+        allergies: ['Peanuts (fake)'],
+        medications: ['Demo Vitamin D 1000 IU (fake)'],
+      };
+      return new HttpResponse(JSON.stringify(payload, null, 2), {
+        headers: {
+          'Content-Type': 'application/json',
+          'Content-Disposition': 'attachment; filename="docforum-fake-export.json"',
+        },
+      });
+    },
+  ),
+
+  http.post(
+    '*/account/delete',
+    respond('json', () => ({
+      success: true,
+      message:
+        'Mock API: account "deleted" (nothing is persisted — fixtures reset on reload).',
+      deletedAt: new Date().toISOString(),
+    })),
+  ),
+];
diff --git a/src/mocks/handlers/auth.ts b/src/mocks/handlers/auth.ts
new file mode 100644
index 0000000..04f6be9
--- /dev/null
+++ b/src/mocks/handlers/auth.ts
@@ -0,0 +1,79 @@
+// Auth endpoints (signup / login / logout / claim-account).
+import { http, HttpResponse } from 'msw';
+import { ADMIN_USER, DOCTOR_USER, FACILITY_USER, MOCK_ACCESS_TOKEN, PATIENT_USER } from '../fixtures';
+import { respond } from '../helpers';
+import { useMockStore } from '../mock-store';
+import type { Role, User } from '../../types/models';
+
+const PERSONAS: Record<Role, User> = {
+  patient: PATIENT_USER,
+  doctor: DOCTOR_USER,
+  facility: FACILITY_USER,
+  admin: ADMIN_USER,
+};
+
+/** The seeded persona for a role, used by the dev panel role switcher. */
+export function personaForRole(role: Role): User {
+  return PERSONAS[role];
+}
+
+/** Find a seeded persona by email (so logging in as one "just works"). */
+export function personaByEmail(email: string): User | undefined {
+  return Object.values(PERSONAS).find((user) => user.email === email);
+}
+
+function sessionFor(user: User) {
+  return { user, accessToken: MOCK_ACCESS_TOKEN };
+}
+
+export const authHandlers = [
+  http.post(
+    '*/auth/signup',
+    respond('json', async ({ request }) => {
+      const body = (await request.json().catch(() => ({}))) as {
+        role?: Role;
+        email?: string;
+        password?: string;
+        fullName?: string;
+      };
+      if (!body.email || !body.password) {
+        return HttpResponse.json({ message: 'Mock API: email and password are required' }, { status: 400 });
+      }
+      const role: Role = body.role === 'doctor' ? 'doctor' : 'patient';
+      return sessionFor({
+        ...PERSONAS[role],
+        id: `usr-mock-${role}-new`,
+        email: body.email,
+        createdAt: new Date().toISOString(),
+        updatedAt: new Date().toISOString(),
+      });
+    }),
+  ),
+
+  http.post(
+    '*/auth/login',
+    respond('json', async ({ request }) => {
+      const body = (await request.json().catch(() => ({}))) as {
+        email?: string;
+        password?: string;
+      };
+      if (!body.email || !body.password) {
+        return HttpResponse.json({ message: 'Mock API: email and password are required' }, { status: 400 });
+      }
+      // Any seeded persona email logs in as that persona directly.
+      const known = personaByEmail(body.email);
+      if (known) return sessionFor(known);
+      // Anything else logs in as the dev panel's active role, keeping the
+      // submitted email so the UI feels real.
+      const role = useMockStore.getState().activeRole;
+      return sessionFor({ ...PERSONAS[role], email: body.email });
+    }),
+  ),
+
+  http.post('*/auth/logout', respond('void', () => null)),
+
+  http.post(
+    '*/auth/claim-account',
+    respond('void', () => null),
+  ),
+];
diff --git a/src/mocks/handlers/care-thread.ts b/src/mocks/handlers/care-thread.ts
new file mode 100644
index 0000000..d6c905d
--- /dev/null
+++ b/src/mocks/handlers/care-thread.ts
@@ -0,0 +1,20 @@
+// Care thread timeline endpoints.
+import { http } from 'msw';
+import { db } from '../db';
+import { notFound, paramId, respond } from '../helpers';
+
+export const careThreadHandlers = [
+  http.get(
+    '*/patients/:profileId/care-threads',
+    respond('list', () => db.careThreads),
+  ),
+
+  http.get(
+    '*/care-threads/:id',
+    respond('json', ({ params }) => {
+      const thread = db.careThreads.find((t) => t.id === paramId(params));
+      if (!thread) return notFound('care thread');
+      return thread;
+    }),
+  ),
+];
diff --git a/src/mocks/handlers/consultation.ts b/src/mocks/handlers/consultation.ts
new file mode 100644
index 0000000..1471382
--- /dev/null
+++ b/src/mocks/handlers/consultation.ts
@@ -0,0 +1,49 @@
+// Consultation note sign-off and addenda endpoints.
+import { http } from 'msw';
+import { db } from '../db';
+import { conflict, notFound, paramId, respond } from '../helpers';
+import type { ConsultationAddendum } from '../../types/models';
+
+export const consultationHandlers = [
+  http.get(
+    '*/consultation-notes/:appointmentId',
+    respond('json', ({ params }) => {
+      const note = db.consultationNotes.find(
+        (n) => n.appointmentId === paramId(params, 'appointmentId'),
+      );
+      if (!note) return notFound('consultation note');
+      return note;
+    }),
+  ),
+
+  http.post(
+    '*/consultation-notes/:id/sign-off',
+    respond('json', ({ params }) => {
+      const note = db.consultationNotes.find((n) => n.id === paramId(params));
+      if (!note) return notFound('consultation note');
+      if (note.signedAt) return conflict('note is already signed off and immutable');
+      note.signedAt = new Date().toISOString();
+      note.signedBy = 'Dr. Demo Doctor (fake)';
+      note.autoSignOffAt = null;
+      return note;
+    }),
+  ),
+
+  http.post(
+    '*/consultation-notes/:id/addenda',
+    respond('json', async ({ params, request }) => {
+      const note = db.consultationNotes.find((n) => n.id === paramId(params));
+      if (!note) return notFound('consultation note');
+      const body = (await request.json().catch(() => ({}))) as { content?: string };
+      if (!body.content) return conflict('addendum content is required');
+      const addendum: ConsultationAddendum = {
+        id: `cad-mock-${db.consultationNotes.length + 1}-${Date.now()}`,
+        noteId: note.id,
+        content: body.content,
+        createdAt: new Date().toISOString(),
+      };
+      note.addenda = [...note.addenda, addendum];
+      return addendum;
+    }),
+  ),
+];
diff --git a/src/mocks/handlers/dependents.ts b/src/mocks/handlers/dependents.ts
new file mode 100644
index 0000000..a4576b1
--- /dev/null
+++ b/src/mocks/handlers/dependents.ts
@@ -0,0 +1,70 @@
+// Dependents CRUD + handover invite endpoints. Specific `/patients/me/…`
+// paths must be registered before generic `/patients/:profileId/…` ones.
+import { http } from 'msw';
+import { db } from '../db';
+import { notFound, paramId, respond } from '../helpers';
+import type { Dependent, DependentInput } from '../../types/models';
+
+export const dependentHandlers = [
+  http.get('*/patients/me/dependents', respond('list', () => db.dependents)),
+
+  http.post(
+    '*/patients/me/dependents',
+    respond('json', async ({ request }) => {
+      const body = (await request.json().catch(() => ({}))) as DependentInput;
+      const now = new Date().toISOString();
+      const dependent: Dependent = {
+        id: `dep-mock-${Date.now()}`,
+        guardianProfileId: db.dependents[0]?.guardianProfileId ?? 'prf-patient-demo',
+        fullName: body.fullName ?? 'Unnamed (fake)',
+        dateOfBirth: body.dateOfBirth ?? '2000-01-01',
+        relationship: body.relationship ?? 'guardian',
+        handoverStatus: 'not_eligible',
+        createdAt: now,
+        updatedAt: now,
+      };
+      db.dependents.push(dependent);
+      return dependent;
+    }),
+  ),
+
+  http.patch(
+    '*/patients/me/dependents/:id',
+    respond('json', async ({ params, request }) => {
+      const dependent = db.dependents.find((d) => d.id === paramId(params));
+      if (!dependent) return notFound('dependent');
+      const body = (await request.json().catch(() => ({}))) as Partial<DependentInput>;
+      Object.assign(dependent, body, { updatedAt: new Date().toISOString() });
+      return dependent;
+    }),
+  ),
+
+  http.post(
+    '*/patients/me/dependents/:id/handover-invite',
+    respond('json', async ({ params, request }) => {
+      const dependent = db.dependents.find((d) => d.id === paramId(params));
+      if (!dependent) return notFound('dependent');
+      const body = (await request.json().catch(() => ({}))) as { email?: string };
+      dependent.handoverStatus = 'invited';
+      dependent.claimEmail = body.email ?? dependent.claimEmail;
+      dependent.claimInviteExpiresAt = new Date(
+        Date.now() + 7 * 24 * 60 * 60 * 1000,
+      ).toISOString();
+      dependent.updatedAt = new Date().toISOString();
+      return dependent;
+    }),
+  ),
+
+  http.post(
+    '*/patients/me/dependents/:id/handover-invite/resend',
+    respond('json', ({ params }) => {
+      const dependent = db.dependents.find((d) => d.id === paramId(params));
+      if (!dependent) return notFound('dependent');
+      dependent.claimInviteExpiresAt = new Date(
+        Date.now() + 7 * 24 * 60 * 60 * 1000,
+      ).toISOString();
+      dependent.updatedAt = new Date().toISOString();
+      return dependent;
+    }),
+  ),
+];
diff --git a/src/mocks/handlers/facility-team.ts b/src/mocks/handlers/facility-team.ts
new file mode 100644
index 0000000..11bb716
--- /dev/null
+++ b/src/mocks/handlers/facility-team.ts
@@ -0,0 +1,115 @@
+// Facility team management and fulfillment queue endpoints.
+import { http } from 'msw';
+import { db } from '../db';
+import { conflict, notFound, paramId, respond } from '../helpers';
+import { FACILITY_USER } from '../fixtures';
+import type {
+  FacilityInvite,
+  FulfillmentActionAttribution,
+  FulfillmentQueueItem,
+} from '../../types/models';
+
+export const facilityTeamHandlers = [
+  http.get('*/facilities/:facilityId/members', respond('list', () => db.facilityMembers)),
+
+  http.get('*/facilities/:facilityId/invites', respond('list', () => db.facilityInvites)),
+
+  http.post(
+    '*/facilities/:facilityId/invites',
+    respond('json', async ({ params, request }) => {
+      const facilityId = paramId(params, 'facilityId');
+      const body = (await request.json().catch(() => ({}))) as {
+        email?: string;
+        role?: FacilityInvite['role'];
+      };
+      const invite: FacilityInvite = {
+        id: `inv-mock-${Date.now()}`,
+        facilityId,
+        email: body.email ?? 'mystery@example.test',
+        role: body.role ?? 'staff',
+        invitedBy: FACILITY_USER.id,
+        invitedAt: new Date().toISOString(),
+        expiresAt: new Date(Date.now() + 7 * 24 * 60 * 60 * 1000).toISOString(),
+        status: 'pending',
+      };
+      db.facilityInvites.push(invite);
+      return invite;
+    }),
+  ),
+
+  http.post(
+    '*/facilities/:facilityId/invites/:inviteId/resend',
+    respond('json', ({ params }) => {
+      const invite = db.facilityInvites.find((i) => i.id === paramId(params, 'inviteId'));
+      if (!invite) return notFound('invite');
+      invite.expiresAt = new Date(Date.now() + 7 * 24 * 60 * 60 * 1000).toISOString();
+      return invite;
+    }),
+  ),
+
+  http.delete(
+    '*/facilities/:facilityId/invites/:inviteId',
+    respond('json', ({ params }) => {
+      const inviteId = paramId(params, 'inviteId');
+      db.facilityInvites = db.facilityInvites.filter((i) => i.id !== inviteId);
+      return { success: true };
+    }),
+  ),
+
+  http.delete(
+    '*/facilities/:facilityId/members/:memberId',
+    respond('json', ({ params }) => {
+      const memberId = paramId(params, 'memberId');
+      const member = db.facilityMembers.find((m) => m.id === memberId);
+      if (!member) return notFound('member');
+      const owners = db.facilityMembers.filter((m) => m.role === 'owner');
+      if (member.role === 'owner' && owners.length <= 1) {
+        return conflict('cannot remove the last owner of a facility');
+      }
+      db.facilityMembers = db.facilityMembers.filter((m) => m.id !== memberId);
+      return {
+        success: true,
+        memberId,
+        sessionsRevoked: true,
+        message: 'Mock API: member removed and their sessions revoked (fixture only).',
+      };
+    }),
+  ),
+
+  http.get(
+    '*/facilities/:facilityId/fulfillment-queue',
+    respond('list', () => db.fulfillmentQueue),
+  ),
+
+  http.post(
+    '*/facilities/:facilityId/fulfillment-queue/:itemId/action',
+    respond('json', async ({ params, request }) => {
+      const item = db.fulfillmentQueue.find(
+        (q) => q.id === paramId(params, 'itemId'),
+      );
+      if (!item) return notFound('fulfillment item');
+      const body = (await request.json().catch(() => ({}))) as {
+        action?: 'fulfilled' | 'rejected';
+        notes?: string;
+      };
+      const action = body.action === 'rejected' ? 'rejected' : 'fulfilled';
+      const attribution: FulfillmentActionAttribution = {
+        action:
+          action === 'rejected'
+            ? 'rejected'
+            : item.orderType === 'prescription'
+              ? 'dispensed'
+              : 'sample_collected',
+        performedByUserId: FACILITY_USER.id,
+        performedByName: 'Frank Facility (fake)',
+        performedByEmail: FACILITY_USER.email,
+        performedByRole: 'owner',
+        timestamp: new Date().toISOString(),
+        notes: body.notes ?? null,
+      };
+      const updated: FulfillmentQueueItem = { ...item, status: action, attribution };
+      db.fulfillmentQueue = db.fulfillmentQueue.map((q) => (q.id === item.id ? updated : q));
+      return updated;
+    }),
+  ),
+];
diff --git a/src/mocks/handlers/facility.ts b/src/mocks/handlers/facility.ts
new file mode 100644
index 0000000..160b8e1
--- /dev/null
+++ b/src/mocks/handlers/facility.ts
@@ -0,0 +1,57 @@
+// Facility finder endpoint with optional distance sorting.
+import { http } from 'msw';
+import { db } from '../db';
+import { respond } from '../helpers';
+import type { FacilityWithDistance } from '../../types/models';
+
+const EARTH_RADIUS_KM = 6371;
+
+function haversineKm(
+  lat1: number,
+  lon1: number,
+  lat2: number,
+  lon2: number,
+): number {
+  const toRad = (deg: number) => (deg * Math.PI) / 180;
+  const dLat = toRad(lat2 - lat1);
+  const dLon = toRad(lon2 - lon1);
+  const a =
+    Math.sin(dLat / 2) ** 2 +
+    Math.cos(toRad(lat1)) * Math.cos(toRad(lat2)) * Math.sin(dLon / 2) ** 2;
+  return 2 * EARTH_RADIUS_KM * Math.asin(Math.sqrt(a));
+}
+
+export const facilityHandlers = [
+  http.get(
+    '*/facilities',
+    respond('list', ({ request }) => {
+      const url = new URL(request.url);
+      const type = url.searchParams.get('type');
+      const query = url.searchParams.get('query');
+      const lat = url.searchParams.get('lat');
+      const lng = url.searchParams.get('lng');
+
+      let facilities: FacilityWithDistance[] = db.facilities.map((f) => ({ ...f }));
+      if (type) facilities = facilities.filter((f) => f.type === type);
+      if (query) {
+        const q = query.toLowerCase();
+        facilities = facilities.filter(
+          (f) => f.name.toLowerCase().includes(q) || f.location?.city.toLowerCase().includes(q),
+        );
+      }
+      if (lat !== null && lng !== null) {
+        const userLat = Number(lat);
+        const userLng = Number(lng);
+        for (const facility of facilities) {
+          facility.distanceKm = facility.location
+            ? Number(
+                haversineKm(userLat, userLng, facility.location.latitude, facility.location.longitude).toFixed(2),
+              )
+            : null;
+        }
+        facilities.sort((a, b) => (a.distanceKm ?? Infinity) - (b.distanceKm ?? Infinity));
+      }
+      return facilities;
+    }),
+  ),
+];
diff --git a/src/mocks/handlers/health-profile.ts b/src/mocks/handlers/health-profile.ts
new file mode 100644
index 0000000..8661aba
--- /dev/null
+++ b/src/mocks/handlers/health-profile.ts
@@ -0,0 +1,69 @@
+// Health profile entries per section.
+import { http } from 'msw';
+import { db } from '../db';
+import { notFound, paramId, respond } from '../helpers';
+import type { HealthEntry, HealthEntryInput } from '../../types/models';
+
+const SECTIONS = ['allergies', 'conditions', 'medications'];
+
+export const healthProfileHandlers = [
+  http.get(
+    '*/patients/:profileId/health/:section',
+    respond('list', ({ params }) => {
+      const profileId = paramId(params, 'profileId');
+      const section = paramId(params, 'section');
+      if (!SECTIONS.includes(section)) return notFound('health section');
+      return db.healthEntries.filter(
+        (e) => e.patientProfileId === profileId && e.section === section,
+      );
+    }),
+  ),
+
+  http.post(
+    '*/patients/:profileId/health',
+    respond('json', async ({ params, request }) => {
+      const profileId = paramId(params, 'profileId');
+      const body = (await request.json().catch(() => ({}))) as HealthEntryInput;
+      const now = new Date().toISOString();
+      const entry: HealthEntry = {
+        id: `hev-mock-${Date.now()}`,
+        patientProfileId: profileId,
+        section: body.section ?? 'allergies',
+        name: body.name ?? 'Unnamed (fake)',
+        details: body.details,
+        version: 1,
+        updatedAt: now,
+        createdAt: now,
+      };
+      db.healthEntries.push(entry);
+      return entry;
+    }),
+  ),
+
+  http.patch(
+    '*/patients/:profileId/health/:entryId',
+    respond('json', async ({ params, request }) => {
+      const entry = db.healthEntries.find((e) => e.id === paramId(params, 'entryId'));
+      if (!entry) return notFound('health entry');
+      const body = (await request.json().catch(() => ({}))) as {
+        name?: string;
+        details?: string;
+      };
+      entry.previousValue = entry.name;
+      if (body.name !== undefined) entry.name = body.name;
+      if (body.details !== undefined) entry.details = body.details;
+      entry.version += 1;
+      entry.updatedAt = new Date().toISOString();
+      return entry;
+    }),
+  ),
+
+  http.delete(
+    '*/patients/:profileId/health/:entryId',
+    respond('void', ({ params }) => {
+      const id = paramId(params, 'entryId');
+      db.healthEntries = db.healthEntries.filter((e) => e.id !== id);
+      return null;
+    }),
+  ),
+];
diff --git a/src/mocks/handlers/insights.ts b/src/mocks/handlers/insights.ts
new file mode 100644
index 0000000..7fd31ef
--- /dev/null
+++ b/src/mocks/handlers/insights.ts
@@ -0,0 +1,28 @@
+// Doctor practice insights endpoint.
+import { http } from 'msw';
+import { db } from '../db';
+import { respond } from '../helpers';
+
+export const insightsHandlers = [
+  http.get(
+    '*/doctor/insights',
+    respond('json', ({ request }) => {
+      const url = new URL(request.url);
+      const preset = url.searchParams.get('preset');
+      const startDate = url.searchParams.get('startDate');
+      const endDate = url.searchParams.get('endDate');
+      const { insights } = db;
+      if (preset || startDate || endDate) {
+        return {
+          ...insights,
+          range: {
+            preset: (preset ?? insights.range.preset) as typeof insights.range.preset,
+            startDate: startDate ?? insights.range.startDate,
+            endDate: endDate ?? insights.range.endDate,
+          },
+        };
+      }
+      return insights;
+    }),
+  ),
+];
diff --git a/src/mocks/handlers/messaging.ts b/src/mocks/handlers/messaging.ts
new file mode 100644
index 0000000..e375d35
--- /dev/null
+++ b/src/mocks/handlers/messaging.ts
@@ -0,0 +1,31 @@
+// Doctor messaging inbox endpoints.
+import { http } from 'msw';
+import { db } from '../db';
+import { notFound, paramId, respond } from '../helpers';
+import type { MessageThread } from '../../types/models';
+
+export const messagingHandlers = [
+  http.get(
+    '*/doctor/messages/threads',
+    respond('list', ({ request }) => {
+      const url = new URL(request.url);
+      const filter = url.searchParams.get('filter');
+      let threads: MessageThread[] = [...db.messageThreads];
+      if (filter === 'unread') threads = threads.filter((t) => t.unreadCount > 0);
+      if (filter === 'closing_soon') threads = threads.filter((t) => t.closingSoon);
+      // Assumed contract: oldest unanswered first.
+      threads.sort((a, b) => a.lastMessageAt.localeCompare(b.lastMessageAt));
+      return { threads, nextCursor: null };
+    }),
+  ),
+
+  http.post(
+    '*/message-threads/:id/read',
+    respond('void', ({ params }) => {
+      const thread = db.messageThreads.find((t) => t.id === paramId(params));
+      if (!thread) return notFound('message thread');
+      thread.unreadCount = 0;
+      return null;
+    }),
+  ),
+];
diff --git a/src/mocks/handlers/payments.ts b/src/mocks/handlers/payments.ts
new file mode 100644
index 0000000..021094f
--- /dev/null
+++ b/src/mocks/handlers/payments.ts
@@ -0,0 +1,94 @@
+// Payments endpoints: wallet link and the payment-intent lifecycle.
+// Everything goes through docforum-core's API shape — no Stellar calls
+// here (hard rule 1). Amounts stay BigInt-as-string.
+import { http } from 'msw';
+import { db } from '../db';
+import { conflict, notFound, paramId, respond } from '../helpers';
+import { FACILITY_ID } from '../fixtures';
+import type { PaymentIntent } from '../../types/models';
+
+const TRANSITIONS: Record<string, PaymentIntent['status']> = {
+  fund: 'escrowed',
+  release: 'released',
+  refund: 'refunded',
+};
+
+export const paymentsHandlers = [
+  http.post(
+    '*/payments/wallet-link',
+    respond('json', async ({ request }) => {
+      const body = (await request.json().catch(() => ({}))) as {
+        stellarPublicKey?: string;
+      };
+      if (!body.stellarPublicKey) {
+        return conflict('stellarPublicKey is required');
+      }
+      const now = new Date().toISOString();
+      db.walletLink = {
+        id: db.walletLink?.id ?? `wln-mock-${Date.now()}`,
+        facilityId: FACILITY_ID,
+        stellarPublicKey: body.stellarPublicKey,
+        createdAt: db.walletLink?.createdAt ?? now,
+        updatedAt: now,
+      };
+      return db.walletLink;
+    }),
+  ),
+
+  http.get('*/payments/wallet-link', respond('nullable', () => db.walletLink)),
+
+  http.post(
+    '*/payments/intents',
+    respond('json', async ({ request }) => {
+      const body = (await request.json().catch(() => ({}))) as Partial<PaymentIntent>;
+      const now = new Date().toISOString();
+      const intent: PaymentIntent = {
+        id: `pin-mock-${Date.now()}`,
+        orderType: body.orderType ?? 'prescription',
+        orderId: body.orderId ?? `ord-mock-${Date.now()}`,
+        status: 'created',
+        patientProfileId: body.patientProfileId ?? 'prf-patient-demo',
+        facilityId: body.facilityId ?? FACILITY_ID,
+        amountStroops: body.amountStroops ?? '100000000',
+        escrowId: null,
+        stellarTxHash: null,
+        sorobanContractId: null,
+        createdAt: now,
+        updatedAt: now,
+      };
+      db.paymentIntents.unshift(intent);
+      return intent;
+    }),
+  ),
+
+  http.get(
+    '*/payments/intents/:id',
+    respond('json', ({ params }) => {
+      const intent = db.paymentIntents.find((i) => i.id === paramId(params));
+      if (!intent) return notFound('payment intent');
+      return intent;
+    }),
+  ),
+
+  ...(['fund', 'release', 'refund'] as const).map((action) =>
+    http.post(
+      `*/payments/intents/:id/${action}`,
+      respond('json', ({ params }) => {
+        const intent = db.paymentIntents.find((i) => i.id === paramId(params));
+        if (!intent) return notFound('payment intent');
+        if (intent.status !== 'created' && action === 'fund') {
+          return conflict(`cannot fund an intent in status "${intent.status}"`);
+        }
+        if (intent.status !== 'escrowed' && (action === 'release' || action === 'refund')) {
+          return conflict(`cannot ${action} an intent in status "${intent.status}"`);
+        }
+        intent.status = TRANSITIONS[action];
+        intent.escrowId = intent.escrowId ?? `esc-mock-${Date.now()} (fake)`;
+        intent.stellarTxHash = `txdemo${Date.now().toString().padStart(52, '0')}`;
+        intent.sorobanContractId = intent.sorobanContractId ?? 'CD mock contract (fake)';
+        intent.updatedAt = new Date().toISOString();
+        return intent;
+      }),
+    ),
+  ),
+];
diff --git a/src/mocks/handlers/queue.ts b/src/mocks/handlers/queue.ts
new file mode 100644
index 0000000..976ba95
--- /dev/null
+++ b/src/mocks/handlers/queue.ts
@@ -0,0 +1,83 @@
+// Doctor queue endpoints: today's appointments, live queue, start/complete
+// visits, running delay with manual override.
+import { http } from 'msw';
+import { db } from '../db';
+import { conflict, notFound, paramId, respond } from '../helpers';
+import type { Appointment, QueueEntry } from '../../types/models';
+
+function deriveQueue(appointments: Appointment[]): QueueEntry[] {
+  return appointments
+    .filter((apt) => apt.checkInAt !== null)
+    .sort((a, b) => String(a.checkInAt).localeCompare(String(b.checkInAt)))
+    .map((apt, index) => ({
+      appointmentId: apt.id,
+      patientProfileId: apt.patientProfileId,
+      fullName: apt.patientName,
+      checkedInAt: String(apt.checkInAt),
+      queuePosition: index + 1,
+      status:
+        apt.status === 'in_progress'
+          ? 'in_progress'
+          : apt.status === 'completed'
+            ? 'completed'
+            : 'checked_in',
+    }));
+}
+
+export const queueHandlers = [
+  http.get(
+    '*/doctor/appointments/today',
+    respond('list', () =>
+      [...db.appointments].sort((a, b) => a.startsAt.localeCompare(b.startsAt)),
+    ),
+  ),
+
+  http.get('*/doctor/queue/today', respond('list', () => deriveQueue(db.appointments))),
+
+  http.post(
+    '*/appointments/:id/start',
+    respond('json', ({ params }) => {
+      const apt = db.appointments.find((a) => a.id === paramId(params));
+      if (!apt) return notFound('appointment');
+      if (apt.status === 'completed') return conflict('cannot start a completed visit');
+      if (apt.status === 'in_progress') return apt; // idempotent, per assumed contract
+      apt.status = 'in_progress';
+      apt.startedAt = new Date().toISOString();
+      return apt;
+    }),
+  ),
+
+  http.post(
+    '*/appointments/:id/complete',
+    respond('json', ({ params }) => {
+      const apt = db.appointments.find((a) => a.id === paramId(params));
+      if (!apt) return notFound('appointment');
+      if (apt.status === 'scheduled' || apt.status === 'checked_in') {
+        return conflict('visit has not started yet');
+      }
+      apt.status = 'completed';
+      apt.completedAt = new Date().toISOString();
+      return apt;
+    }),
+  ),
+
+  http.get('*/doctor/queue/running-delay', respond('json', () => db.runningDelay)),
+
+  http.patch(
+    '*/doctor/queue/running-delay',
+    respond('json', async ({ request }) => {
+      const body = (await request.json().catch(() => ({}))) as {
+        manualOverrideMin?: number | null;
+      };
+      const override = body.manualOverrideMin ?? null;
+      db.runningDelay = {
+        ...db.runningDelay,
+        manualOverrideMin: override,
+        effectiveDelayMin: override ?? db.runningDelay.computedDelayMin,
+      };
+      return db.runningDelay;
+    }),
+  ),
+];
+
+export { deriveQueue };
diff --git a/src/mocks/helpers.ts b/src/mocks/helpers.ts
new file mode 100644
index 0000000..ca1532e
--- /dev/null
+++ b/src/mocks/helpers.ts
@@ -0,0 +1,72 @@
+// Shared plumbing for mock handlers: applies the dev-panel scenario
+// (forced errors, empty datasets) and artificial latency uniformly, so
+// individual handlers only express the happy path + domain logic.
+import { HttpResponse, type PathParams } from 'msw';
+import { useMockStore } from './mock-store';
+
+type AnyHttpResponse = HttpResponse<any>;
+
+export interface MockResolverArgs {
+  params: PathParams;
+  request: Request;
+}
+
+export type MockResolveFn = (
+  args: MockResolverArgs,
+) => unknown | Promise<unknown>;
+
+export type ResponseKind =
+  | 'json' // normal JSON body (mutations and singletons)
+  | 'list' // array body — becomes [] under the "empty" scenario
+  | 'nullable' // optional singleton — becomes null under the "empty" scenario
+  | 'void'; // body-less success
+
+const FORCED_ERROR_MESSAGE = 'Mock scenario: forced server error (dev panel)';
+
+async function applyScenario(): Promise<AnyHttpResponse | null> {
+  const { scenario, latencyMs } = useMockStore.getState();
+  if (latencyMs > 0) {
+    await new Promise((resolve) => setTimeout(resolve, latencyMs));
+  }
+  if (scenario === 'error') {
+    return HttpResponse.json({ message: FORCED_ERROR_MESSAGE }, { status: 500 });
+  }
+  return null;
+}
+
+/**
+ * Wrap a mock resolver so every endpoint honours the dev panel's scenario
+ * and latency settings. Resolvers may return a bare `HttpResponse` to
+ * control status codes (404/409); anything else is JSON-serialized.
+ */
+export function respond(
+  kind: ResponseKind,
+  resolve: MockResolveFn,
+): (args: MockResolverArgs) => Promise<AnyHttpResponse> {
+  return async ({ params, request }) => {
+    const { scenario } = useMockStore.getState();
+    const forced = await applyScenario();
+    if (forced) return forced;
+    if (scenario === 'empty' && kind === 'list') return HttpResponse.json([]);
+    if (scenario === 'empty' && kind === 'nullable') return HttpResponse.json(null);
+
+    const body = await resolve({ params, request });
+    if (body instanceof HttpResponse) return body;
+    if (kind === 'void') return HttpResponse.json(null);
+    return HttpResponse.json(body ?? null);
+  };
+}
+
+/** 404 helper with the `{ message }` envelope api-client.ts expects. */
+export function notFound(what: string): AnyHttpResponse {
+  return HttpResponse.json({ message: `Mock API: ${what} not found` }, { status: 404 });
+}
+
+/** 409 helper with the `{ message }` envelope api-client.ts expects. */
+export function conflict(message: string): AnyHttpResponse {
+  return HttpResponse.json({ message: `Mock API: ${message}` }, { status: 409 });
+}
+
+export function paramId(params: PathParams, name = 'id'): string {
+  return String(params[name]);
+}
diff --git a/src/mocks/mock-store.ts b/src/mocks/mock-store.ts
new file mode 100644
index 0000000..e4476f1
--- /dev/null
+++ b/src/mocks/mock-store.ts
@@ -0,0 +1,25 @@
+// Dev-panel state for mock mode (issue #95). This is client-only UI state
+// for the mock tooling itself — not application state, and not part of
+// src/store/ (that directory is app state per ARCHITECTURE_ESSENTIALS.md).
+import { create } from 'zustand';
+import type { Role } from '../types/models';
+
+export type MockScenario = 'normal' | 'empty' | 'error';
+
+interface MockState {
+  scenario: MockScenario;
+  latencyMs: number;
+  activeRole: Role;
+  setScenario: (scenario: MockScenario) => void;
+  setLatencyMs: (ms: number) => void;
+  setActiveRole: (role: Role) => void;
+}
+
+export const useMockStore = create<MockState>((set) => ({
+  scenario: 'normal',
+  latencyMs: 0,
+  activeRole: 'patient',
+  setScenario: (scenario) => set({ scenario }),
+  setLatencyMs: (latencyMs) => set({ latencyMs }),
+  setActiveRole: (activeRole) => set({ activeRole }),
+}));
diff --git a/src/mocks/roles.ts b/src/mocks/roles.ts
new file mode 100644
index 0000000..d553167
--- /dev/null
+++ b/src/mocks/roles.ts
@@ -0,0 +1,45 @@
+// Role-switching helpers for mock mode: applies a seeded persona to the
+// app's real auth/profile stores and routes to that role's home screen.
+import { useAuthStore } from '../store/auth-store';
+import { useProfileStore } from '../store/profile-store';
+import { DEPENDENT_PROFILE_ID, MOCK_ACCESS_TOKEN, PATIENT_PROFILE_ID } from './fixtures';
+import { personaForRole } from './handlers/auth';
+import { useMockStore } from './mock-store';
+import type { Role } from '../types/models';
+
+const HOME_BY_ROLE: Record<Role, string> = {
+  patient: '#/patient',
+  doctor: '#/doctor',
+  facility: '#/facility',
+  admin: '#/admin',
+};
+
+/**
+ * Sign in as the seeded persona for `role` (or switch to it). Sets the
+ * app's real auth session — mock handlers only care about the route, not
+ * the token — and routes to the role's dashboard.
+ */
+export function activateMockRole(
+  role: Role,
+  options: { navigate?: boolean } = {},
+): void {
+  const { navigate = true } = options;
+  useMockStore.getState().setActiveRole(role);
+  const persona = personaForRole(role);
+  useAuthStore.getState().setSession(persona, MOCK_ACCESS_TOKEN);
+  useProfileStore.getState().setProfiles(
+    role === 'patient'
+      ? [
+          { id: PATIENT_PROFILE_ID, fullName: 'Pat Placeholder (fake)', isSelf: true },
+          { id: DEPENDENT_PROFILE_ID, fullName: 'Tyke Placeholder (fake)', isSelf: false },
+        ]
+      : [],
+  );
+  if (navigate) window.location.hash = HOME_BY_ROLE[role];
+}
+
+/** Clear the session and land on the login screen (to test the real flow). */
+export function mockSignOut(): void {
+  useAuthStore.getState().clearSession();
+  window.location.hash = '#/login';
+}
diff --git a/src/mocks/setup.tsx b/src/mocks/setup.tsx
new file mode 100644
index 0000000..9a5e37e
--- /dev/null
+++ b/src/mocks/setup.tsx
@@ -0,0 +1,32 @@
+// Mock-mode bootstrap. Dynamically imported by main.tsx only when running
+// `npm run dev:mock` (a DEV build with VITE_ENABLE_MOCKS=true) — this
+// keeps MSW, the fixtures, and the dev panel entirely out of production
+// bundles (enforced in CI by `npm run check:dist`).
+import { createRoot } from 'react-dom/client';
+import { worker } from './browser';
+import { DevPanel } from './DevPanel';
+import { activateMockRole } from './roles';
+import { useMockStore } from './mock-store';
+
+/**
+ * Start the mock API and mount the dev panel. Called by main.tsx via
+ * top-level await BEFORE the first React render, so the persona session
+ * exists when route guards first evaluate — otherwise RequireAuth would
+ * bounce a deep-linked protected route to #/login before the mocks boot.
+ */
+export function startMockApi(): void {
+  worker.start({ onUnhandledRequest: 'bypass' });
+
+  // Sign the persona in immediately. Navigate to the role's home screen
+  // unless the URL already deep-links a route, which we leave untouched.
+  // Logging in through the real login screen works too (handlers answer
+  // any credentials).
+  const hash = window.location.hash;
+  const deepLinked = hash !== '' && hash !== '#/' && hash !== '#';
+  activateMockRole(useMockStore.getState().activeRole, { navigate: !deepLinked });
+
+  const panelRoot = document.createElement('div');
+  panelRoot.id = 'mock-dev-panel-root';
+  document.body.appendChild(panelRoot);
+  createRoot(panelRoot).render(<DevPanel />);
+}
diff --git a/src/query-client.ts b/src/query-client.ts
new file mode 100644
index 0000000..ef21bc0
--- /dev/null
+++ b/src/query-client.ts
@@ -0,0 +1,13 @@
+// Single shared React Query client. Exported so the mock dev panel
+// (issue #95) can invalidate every cache when the scenario/role changes —
+// main.tsx mounts the same instance, so app behaviour is unchanged.
+import { QueryClient } from '@tanstack/react-query';
+
+export const queryClient = new QueryClient({
+  defaultOptions: {
+    queries: {
+      retry: 1,
+      refetchOnWindowFocus: false,
+    },
+  },
+});
diff --git a/src/vite-env.d.ts b/src/vite-env.d.ts
index d43868c..ebce044 100644
--- a/src/vite-env.d.ts
+++ b/src/vite-env.d.ts
@@ -2,6 +2,8 @@
 
 interface ImportMetaEnv {
   readonly VITE_API_BASE_URL?: string;
+  /** Set only by `npm run dev:mock` — enables the MSW mock API (issue #95). */
+  readonly VITE_ENABLE_MOCKS?: string;
 }
 
 interface ImportMeta {