diff --git a/.env.example b/.env.example
index 3906943..87dc6d6 100644
--- a/.env.example
+++ b/.env.example
@@ -93,6 +93,9 @@ GRACEFUL_SHUTDOWN_TIMEOUT_MS=10000
 # ── Rate limiting ───────────────────────────────────────────────────────────
 # [optional] Shared store for multi-instance deployments (in-memory otherwise)
 REDIS_URL=redis://localhost:6379
+# Publisher registration (POST /publishers): 10 registrations per IP per hour
+RATE_LIMIT_REGISTER_IP_MAX=10
+RATE_LIMIT_REGISTER_IP_WINDOW_MS=3600000
 RATE_LIMIT_VERIFY_IP_MAX=10
 RATE_LIMIT_VERIFY_IP_WINDOW_MS=60000
 RATE_LIMIT_VERIFY_WALLET_MAX=5
diff --git a/README.md b/README.md
index 4d68bc1..d6d55a9 100644
--- a/README.md
+++ b/README.md
@@ -150,6 +150,23 @@ const expected = crypto.createHmac("sha256", secret).update(rawBody).digest("hex
 Failures are retried with exponential backoff (`WEBHOOK_MAX_ATTEMPTS`).
 Private and loopback URLs are rejected.
 
+## Rate limiting
+
+All rate limits use a sliding-window algorithm. Responses include `RateLimit-Limit`, `RateLimit-Remaining`, and `RateLimit-Reset` headers. Blocked requests return `429` with `{ "error": "Too many requests", "code": "RATE_LIMITED", "retryAfterSeconds": N }` and a `Retry-After` header.
+
+| Limiter | Scope | Default | Env vars |
+|---|---|---|---|
+| Registration | IP | 10 per hour | `RATE_LIMIT_REGISTER_IP_MAX`, `RATE_LIMIT_REGISTER_IP_WINDOW_MS` |
+| Verify-content | IP | 10 / min | `RATE_LIMIT_VERIFY_IP_MAX`, `RATE_LIMIT_VERIFY_IP_WINDOW_MS` |
+| Verify-content | Wallet | 5 / hour | `RATE_LIMIT_VERIFY_WALLET_MAX`, `RATE_LIMIT_VERIFY_WALLET_WINDOW_MS` |
+| Publish resource | IP | 20 / min | `RATE_LIMIT_PUBLISH_IP_MAX`, `RATE_LIMIT_PUBLISH_IP_WINDOW_MS` |
+| Publish resource | Wallet | 10 / hour | `RATE_LIMIT_PUBLISH_WALLET_MAX`, `RATE_LIMIT_PUBLISH_WALLET_WINDOW_MS` |
+| Publisher API routes | Per publisher | 60 RPM | `PUBLISHER_RATE_LIMIT_RPM_DEFAULT`, `PUBLISHER_RATE_LIMIT_MAX_RPM` |
+
+**Registration rate limit** (`POST /publishers`): at most `RATE_LIMIT_REGISTER_IP_MAX` (default **10**) registrations per IP within `RATE_LIMIT_REGISTER_IP_WINDOW_MS` (default **1 hour**). This prevents bulk account and API-key creation from a single IP address.
+
+Publishers can inspect and override their own per-publisher limit via `PATCH /publishers/me/rate-limit` (up to `PUBLISHER_RATE_LIMIT_MAX_RPM`).
+
 ## Environment variables
 
 See [`.env.example`](./.env.example) for the full list and descriptions.
diff --git a/src/config.ts b/src/config.ts
index b0b8fe3..c2c013f 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -226,6 +226,8 @@ const envSchema = z.object({
   VERIFICATION_COMPLETION_COST_PER_1M: z.coerce.number().nonnegative().default(15),
 
   // Rate limiting (verify-content + publish)
+  RATE_LIMIT_REGISTER_IP_MAX: z.coerce.number().default(10),
+  RATE_LIMIT_REGISTER_IP_WINDOW_MS: z.coerce.number().default(3_600_000),
   RATE_LIMIT_VERIFY_IP_MAX: z.coerce.number().default(10),
   RATE_LIMIT_VERIFY_IP_WINDOW_MS: z.coerce.number().default(60_000),
   RATE_LIMIT_VERIFY_WALLET_MAX: z.coerce.number().default(5),
diff --git a/src/middleware/rateLimiters.ts b/src/middleware/rateLimiters.ts
index c7fc7aa..2fb9e61 100644
--- a/src/middleware/rateLimiters.ts
+++ b/src/middleware/rateLimiters.ts
@@ -17,6 +17,13 @@ export const verifyIpRateLimit: RequestHandler = createIpRateLimiter(
   "verify_ip",
 );
 
+export const registerIpRateLimit: RequestHandler = createIpRateLimiter(
+  store,
+  "register",
+  config.RATE_LIMIT_REGISTER_IP_MAX,
+  config.RATE_LIMIT_REGISTER_IP_WINDOW_MS,
+  "register_ip",
+);
 export const verifyWalletRateLimit: RequestHandler = createWalletRateLimiter(
   store,
   "verify",
diff --git a/src/routes/publishers.register-rate-limit.test.ts b/src/routes/publishers.register-rate-limit.test.ts
new file mode 100644
index 0000000..3761f6c
--- /dev/null
+++ b/src/routes/publishers.register-rate-limit.test.ts
@@ -0,0 +1,199 @@
+/**
+ * Tests for the IP rate limit on POST /publishers (#38).
+ *
+ * Split into two layers:
+ *  1. Unit tests — exercise `createIpRateLimiter` directly with a controlled
+ *     in-memory store and a fake handler, so window/clock/limit are all
+ *     under our control.
+ *  2. Integration test — verify that publishers.ts wires the limiter; the
+ *     limiter is replaced with a middleware that rejects on demand so the
+ *     integration test is deterministic without touching real config.
+ */
+import { describe, it, expect, vi } from "vitest";
+import express from "express";
+import request from "supertest";
+import { createIpRateLimiter, RATE_LIMITED } from "../middleware/rateLimit.js";
+import { MemorySlidingWindowStore } from "../lib/rateLimit/stores.js";
+
+// ── 1. Unit tests — createIpRateLimiter behaviour ─────────────────────────
+
+describe("createIpRateLimiter — registration window", () => {
+  function buildApp(max: number, windowMs: number, clockFn?: () => number) {
+    const store = new MemorySlidingWindowStore(clockFn);
+    const app = express();
+    app.use(createIpRateLimiter(store, "register", max, windowMs, "register_ip"));
+    app.post("/publishers", (_req, res) => res.status(201).json({ ok: true }));
+    return app;
+  }
+
+  it("allows requests up to the limit and sets RateLimit-* headers", async () => {
+    const app = buildApp(3, 60_000);
+
+    const r1 = await request(app).post("/publishers").send({});
+    expect(r1.status).toBe(201);
+    expect(r1.headers["ratelimit-limit"]).toBe("3");
+    expect(Number(r1.headers["ratelimit-remaining"])).toBe(2);
+
+    const r2 = await request(app).post("/publishers").send({});
+    expect(r2.status).toBe(201);
+    expect(Number(r2.headers["ratelimit-remaining"])).toBe(1);
+
+    const r3 = await request(app).post("/publishers").send({});
+    expect(r3.status).toBe(201);
+    expect(Number(r3.headers["ratelimit-remaining"])).toBe(0);
+  });
+
+  it("returns 429 after the limit is exceeded", async () => {
+    const app = buildApp(2, 60_000);
+
+    await request(app).post("/publishers").send({}); // 1 — ok
+    await request(app).post("/publishers").send({}); // 2 — ok (limit reached)
+
+    const res = await request(app).post("/publishers").send({}); // 3 — blocked
+    expect(res.status).toBe(429);
+    expect(res.body).toMatchObject({
+      error: "Too many requests",
+      code: RATE_LIMITED,
+      retryAfterSeconds: expect.any(Number),
+    });
+  });
+
+  it("429 response includes Retry-After and RateLimit-Remaining=0 headers", async () => {
+    const app = buildApp(1, 60_000);
+
+    await request(app).post("/publishers").send({});
+    const res = await request(app).post("/publishers").send({});
+
+    expect(res.status).toBe(429);
+    expect(Number(res.headers["retry-after"])).toBeGreaterThan(0);
+    expect(res.headers["ratelimit-remaining"]).toBe("0");
+    expect(Number(res.headers["ratelimit-reset"])).toBeGreaterThan(0);
+  });
+
+  it("resets the counter after the window elapses", async () => {
+    let ts = 0;
+    const windowMs = 60_000;
+    const app = buildApp(1, windowMs, () => ts);
+
+    const r1 = await request(app).post("/publishers").send({});
+    expect(r1.status).toBe(201);
+
+    const blocked = await request(app).post("/publishers").send({});
+    expect(blocked.status).toBe(429);
+
+    // Advance clock past the window — the old request drops out of the
+    // sliding window, so the limit resets.
+    ts += windowMs + 1;
+
+    const r3 = await request(app).post("/publishers").send({});
+    expect(r3.status).toBe(201);
+  });
+
+  it("tracks counters per IP independently (independent stores)", async () => {
+    // Confirm that two independent stores share no state (each represents a
+    // different server instance or IP namespace in this test).
+    const store1 = new MemorySlidingWindowStore();
+    const app1 = express();
+    app1.use(createIpRateLimiter(store1, "register", 1, 60_000, "register_ip"));
+    app1.post("/publishers", (_req, res) => res.status(201).json({ ok: true }));
+
+    const store2 = new MemorySlidingWindowStore();
+    const app2 = express();
+    app2.use(createIpRateLimiter(store2, "register", 1, 60_000, "register_ip"));
+    app2.post("/publishers", (_req, res) => res.status(201).json({ ok: true }));
+
+    // Exhaust app1.
+    await request(app1).post("/publishers").send({});
+    const blocked = await request(app1).post("/publishers").send({});
+    expect(blocked.status).toBe(429);
+
+    // app2 has its own store — still has capacity.
+    const ok = await request(app2).post("/publishers").send({});
+    expect(ok.status).toBe(201);
+  });
+});
+
+// ── 2. Integration test — publishers router wires the limiter ──────────────
+//
+// Replace rateLimiters with a controlled implementation so we can verify the
+// real route returns 429 when registerIpRateLimit fires.
+
+vi.mock("../db/schema.js", () => ({
+  publishers: { __table: "publishers" },
+  resources: { __table: "resources" },
+  payments: { __table: "payments" },
+}));
+
+vi.mock("../db/client.js", () => ({
+  db: {
+    select: () => ({ from: () => ({ where: () => Promise.resolve([]) }) }),
+  },
+}));
+
+vi.mock("../config.js", () => ({
+  config: {
+    BASE_URL: "http://localhost:4021",
+    PUBLISHER_RATE_LIMIT_RPM_DEFAULT: 60,
+    PUBLISHER_RATE_LIMIT_MAX_RPM: 10_000,
+    PUBLISHER_RATE_LIMIT_WINDOW_MS: 60_000,
+    RATE_LIMIT_REGISTER_IP_MAX: 10,
+    RATE_LIMIT_REGISTER_IP_WINDOW_MS: 3_600_000,
+  },
+}));
+
+vi.mock("../services/publisherService.js", () => ({
+  registerPublisher: vi.fn().mockResolvedValue({
+    publisher: {
+      id: "pub-1",
+      name: "Alice",
+      email: "alice@example.com",
+      walletAddress: "GALICE",
+      createdAt: new Date("2026-01-01"),
+    },
+    apiKey: "mv_freshkey",
+  }),
+  getPublisherResources: vi.fn().mockResolvedValue([]),
+  rotateApiKey: vi.fn().mockResolvedValue("mv_newkey"),
+}));
+
+// Build the registerIpRateLimit inside the factory (no outer-scope variables).
+vi.mock("../middleware/rateLimiters.js", async () => {
+  const { createIpRateLimiter: factory } = await import("../middleware/rateLimit.js");
+  const { MemorySlidingWindowStore: Store } = await import("../lib/rateLimit/stores.js");
+  // Limit of 2 so the integration test triggers 429 after two requests.
+  const integrationStore = new Store();
+  return {
+    registerIpRateLimit: factory(integrationStore, "register", 2, 60_000, "register_ip"),
+    publisherRateLimit: (_req: unknown, _res: unknown, next: () => void) => next(),
+  };
+});
+
+import publisherRouter from "./publishers.js";
+import { errorHandler } from "../middleware/errorHandler.js";
+
+function createIntegrationApp() {
+  const app = express();
+  app.use(express.json());
+  app.use(publisherRouter);
+  app.use(errorHandler);
+  return app;
+}
+
+const validBody = {
+  name: "Alice",
+  email: "alice@example.com",
+  walletAddress: "GALICE",
+};
+
+describe("POST /publishers — registerIpRateLimit wired into route (#38)", () => {
+  it("returns 429 once the per-IP limit is reached on the real route", async () => {
+    const app = createIntegrationApp();
+
+    await request(app).post("/publishers").send(validBody); // 1 — ok
+    await request(app).post("/publishers").send(validBody); // 2 — ok (limit reached)
+
+    const res = await request(app).post("/publishers").send(validBody); // 3 — blocked
+    expect(res.status).toBe(429);
+    expect(res.body.code).toBe(RATE_LIMITED);
+  });
+});
diff --git a/src/routes/publishers.test.ts b/src/routes/publishers.test.ts
index 4dde7a8..7bb94e6 100644
--- a/src/routes/publishers.test.ts
+++ b/src/routes/publishers.test.ts
@@ -96,13 +96,16 @@ describe("POST /publishers — registration (#294)", () => {
     mockRegisterPublisher.mockReset();
   });
 
+  // A real Stellar ed25519 public key (G..., 56 chars) so the schema passes.
+  const VALID_WALLET = "GDEJJLXV2CNHF5HEGX34MU4G6L4PRVUAGD4ANF77ZDYTQJKSDSDYVVI6";
+
   it("registers a publisher and returns the one-time API key", async () => {
     mockRegisterPublisher.mockResolvedValue({
       publisher: {
         id: "pub-1",
         name: "Alice",
         email: "alice@example.com",
-        walletAddress: "GALICE",
+        walletAddress: VALID_WALLET,
         createdAt: new Date("2026-01-01"),
       },
       apiKey: "mv_freshkey",
@@ -111,7 +114,7 @@ describe("POST /publishers — registration (#294)", () => {
     const res = await request(createTestApp()).post("/publishers").send({
       name: "Alice",
       email: "alice@example.com",
-      walletAddress: "GALICE",
+      walletAddress: VALID_WALLET,
     });
 
     expect(res.status).toBe(201);
@@ -119,13 +122,13 @@ describe("POST /publishers — registration (#294)", () => {
       id: "pub-1",
       name: "Alice",
       email: "alice@example.com",
-      walletAddress: "GALICE",
+      walletAddress: VALID_WALLET,
       apiKey: "mv_freshkey",
     });
     expect(mockRegisterPublisher).toHaveBeenCalledWith({
       name: "Alice",
       email: "alice@example.com",
-      walletAddress: "GALICE",
+      walletAddress: VALID_WALLET,
     });
   });
 
@@ -133,7 +136,7 @@ describe("POST /publishers — registration (#294)", () => {
     const res = await request(createTestApp()).post("/publishers").send({
       name: "Alice",
       email: "not-an-email",
-      walletAddress: "GALICE",
+      walletAddress: VALID_WALLET,
     });
 
     expect(res.status).toBe(400);
@@ -143,7 +146,7 @@ describe("POST /publishers — registration (#294)", () => {
   it("returns 400 when a required field is missing", async () => {
     const res = await request(createTestApp()).post("/publishers").send({
       email: "alice@example.com",
-      walletAddress: "GALICE",
+      walletAddress: VALID_WALLET,
     });
 
     expect(res.status).toBe(400);
@@ -154,7 +157,7 @@ describe("POST /publishers — registration (#294)", () => {
     const res = await request(createTestApp()).post("/publishers").send({
       name: "Alice",
       email: "alice@example.com",
-      walletAddress: "GALICE",
+      walletAddress: VALID_WALLET,
       isAdmin: true,
     });
 
@@ -170,7 +173,7 @@ describe("POST /publishers — registration (#294)", () => {
     const res = await request(createTestApp()).post("/publishers").send({
       name: "Alice",
       email: "alice@example.com",
-      walletAddress: "GALICE",
+      walletAddress: VALID_WALLET,
     });
 
     expect(res.status).toBe(409);
@@ -187,7 +190,7 @@ describe("POST /publishers — registration (#294)", () => {
     const res = await request(createTestApp()).post("/publishers").send({
       name: "Alice",
       email: "alice@example.com",
-      walletAddress: "GALICE",
+      walletAddress: VALID_WALLET,
     });
 
     expect(res.status).toBe(409);
@@ -200,7 +203,7 @@ describe("POST /publishers — registration (#294)", () => {
     const res = await request(createTestApp()).post("/publishers").send({
       name: "Alice",
       email: "alice@example.com",
-      walletAddress: "GALICE",
+      walletAddress: VALID_WALLET,
     });
 
     expect(res.status).toBe(500);
diff --git a/src/routes/publishers.ts b/src/routes/publishers.ts
index 979dd07..d0a689f 100644
--- a/src/routes/publishers.ts
+++ b/src/routes/publishers.ts
@@ -2,7 +2,7 @@ import { Router, type Router as RouterType } from "express";
 import type { z } from "zod/v4";
 import { AppError } from "../lib/errors.js";
 import { apiKeyAuth } from "../middleware/apiKeyAuth.js";
-import { publisherRateLimit } from "../middleware/rateLimiters.js";
+import { publisherRateLimit, registerIpRateLimit } from "../middleware/rateLimiters.js";
 import { validate } from "../middleware/validate.js";
 import {
   publisherRegisterSchema,
@@ -21,7 +21,7 @@ const router: RouterType = Router();
 type UpdateWebhookConfig = z.infer<typeof updateWebhookConfigSchema>;
 
 // POST /publishers — register a new publisher (public)
-router.post("/publishers", validate(publisherRegisterSchema), async (req, res) => {
+router.post("/publishers", registerIpRateLimit, validate(publisherRegisterSchema), async (req, res) => {
   try {
     const { publisher, apiKey } = await registerPublisher(req.body);
     res.status(201).json({
diff --git a/src/routes/publishers.webhooks.test.ts b/src/routes/publishers.webhooks.test.ts
index a70eb31..50be320 100644
--- a/src/routes/publishers.webhooks.test.ts
+++ b/src/routes/publishers.webhooks.test.ts
@@ -55,6 +55,7 @@ vi.mock("../middleware/apiKeyAuth.js", () => ({
 
 vi.mock("../middleware/rateLimiters.js", () => ({
   publisherRateLimit: (_req: any, _res: any, next: any) => next(),
+  registerIpRateLimit: (_req: any, _res: any, next: any) => next(),
 }));
 
 vi.mock("../services/publisherService.js", () => ({