API Lens — Reverse API Engineer

Record a site's API calls, group them into endpoints, and export OpenAPI + typed clients in TS, JS, Python & Go. Local-first.

Every website runs on APIs. API Lens shows you the ones your browser is already calling — and turns them into a client you own. Press ● Record on any tab and browse the site normally. API Lens captures the fetch, XHR and beacon calls the page makes, then: • Groups them into endpoint templates — /users/42 and /users/43 become GET /users/{id} • Infers request/response JSON schemas across samples, including required fields and the auth style the site uses • Filters out telemetry noise (analytics, tracking, beacons) automatically — it's hidden by default and always excluded from exports One click exports: • OpenAPI 3.1 spec (JSON) • Typed clients in TypeScript, JavaScript, Python (httpx) and Go • HAR 1.2 session file Saved sessions let you reload a recording later and re-export in any language. Generated clients are auth-aware, with secret values left as placeholders unless you explicitly tick "include secrets in exports". OPTIONAL AI ENHANCE: with your own OpenRouter key, an AI pass names endpoints and writes descriptions — it receives endpoint shapes only (names, field types, counts), never credential values, never body values. Without a key, everything works deterministically. PRIVATE BY DESIGN: no servers, no analytics, no account. Recording is per-tab and off until you press Record. Sessions live in your browser's local storage. Exports redact Authorization headers, cookies, API keys and password/token fields by default. Free while in beta. API Lens Pro ($12/mo) planned: team session libraries, diffing between sessions, and one-click MCP tool export.