Langfuse Session Viewer

A small local/desktop app to browse Langfuse sessions with a readable chat transcript and inline tool calls. It runs as a no‑deps Node server or as a desktop app via Electron. Secrets never reach the browser.

What it does

• Lists sessions with pagination.
• Shows a chat transcript (user/assistant/tool), with inline tool calls and collapsible JSON details.
• Lets you view raw session JSON when needed.

How to run

• Web: node server.js → open http://localhost:5173
• Desktop: npm install → npm run dev:desktop (optional: npm run build:desktop)

Config

• .env (optional in dev): LANGFUSE_PUBLIC_KEY, LANGFUSE_SECRET_KEY, LANGFUSE_BASE_URL (default https://cloud.langfuse.com), PORT (default 5173).
• Desktop adds a “Set Keys” button to enter/update keys without editing .env.

Security

• Keys stay server‑side (Node/Electron main); the UI only calls the local proxy (/api).
• Desktop stores keys at userData/credentials.json (0600 perms). .env can override in dev.

CLI (optional)

• Fetch via Public API: LANGFUSE_PUBLIC_KEY=pk LANGFUSE_SECRET_KEY=sk node scripts/langfuse_fetch.js