# apifacts

> Open registry of verified, dated facts about what third-party machine interfaces (HTTP APIs, SDKs, CLIs) actually do today. Facts come from deterministic probes; no language model is in the verification path.

Registry version 2026-10-27. Code MIT, data CC BY 4.0. Source: https://github.com/Illouminus/apifacts

## API

- [POST /v0/check](https://apifacts.dev/v0/check): send the failing request as `{"target":{"method":"GET","url":"https://api.stripe.com/v1/customers"},"error":{"status":401,"body_excerpt":"..."}}`; get the matching facts with typed fixes. A target on a registered template is stored as one normalized observation (no bodies, headers, query strings or raw IPs).
- [GET /v0/services](https://apifacts.dev/v0/services): services, hosts and fact counts
- [GET /v0/facts/{service}](https://apifacts.dev/v0/facts/stripe): every fact of a service (JSON)
- [GET /v0/facts/{service}/{slug}](https://apifacts.dev/v0/facts/stripe/missing-api-key-401): one fact
- [OpenAPI schema](https://apifacts.dev/openapi.json) · [Swagger UI](https://apifacts.dev/docs)
- [Fact schema](https://github.com/Illouminus/apifacts/blob/main/schema/fact.schema.json)

## Services

- [GitHub REST API](https://apifacts.dev/github/): 23 facts
- [Google Calendar API](https://apifacts.dev/google-calendar/): 14 facts
- [Cloud Firestore (Firebase) REST API](https://apifacts.dev/google-firestore/): 18 facts
- [Gemini API](https://apifacts.dev/google-gemini/): 17 facts
- [Google Sheets API](https://apifacts.dev/google-sheets/): 20 facts
- [PyPI (Python Package Index)](https://apifacts.dev/pypi/): 16 facts
- [Salesforce Platform REST API](https://apifacts.dev/salesforce/): 18 facts
- [Solana JSON-RPC (public mainnet endpoint)](https://apifacts.dev/solana/): 14 facts
- [Stripe API](https://apifacts.dev/stripe/): 26 facts
- [Telegram Bot API](https://apifacts.dev/telegram/): 16 facts

## Optional

- [Registry index](https://apifacts.dev/registry)
- Install: `pip install apifacts-pytest` (pytest plugin) · `uvx apifacts check <url>` (CLI)
- Probe opt-out and contact: edouard@baillot.dev