Telltale — API Drift & Schema Detector

Passively learns your API's contract from real browser traffic and tells you the moment a response drifts. Local-first.

Telltale watches the API traffic your web app actually makes (`fetch` and `XMLHttpRequest`), infers a schema for each endpoint from the responses it sees, and alerts you the instant a response drifts from the learned contract — a vanished field, a type change, a first-ever `null`, a new status code, an unexpected field. The contract writes itself. No spec to author, no test harness, no backend cooperation. Install it, use your app normally, and Telltale learns your endpoints and starts catching breakage the moment it lands in the tab. • Zero-config — install, browse, done. • High-signal drift detection — confidence-gated so it doesn't cry wolf. • Living, exportable contract — TypeScript, Zod, JSON Schema, OpenAPI. • Local-first & private — stores shapes, not values; nothing leaves your device. • Heuristic PII redaction — auto-strips email/token/credential-shaped values. • Environment-aware — diff the same contract across prod vs staging.