Detect API schema drift and response anomalies. Catch breaking changes with contract testing and JSON schema checks.
Users
3
0 in 30 days
Rating
0.0 / 5
unchanged in 30 days
Ratings
0
0 in 30 days
Store rank
#325K
#256K among extensions
Version
1.1.0
updated 14 Aug 2026
Users
monthly, 4 months
Latest, 15 Oct 2026:3 usersMove the mouse over the chart for any month
Ratings count
monthly, 4 months
Latest, 15 Oct 2026:0 ratingsMove the mouse over the chart for any month
The Chrome Web Store rounds user counts down to the leading digit, so the user line moves in steps. The ratings count is exact and is the better signal of real adoption.
About Telltale - API Drift & Schema Monitor (Deep)
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.