APIs.guru vs Beeceptor

APIs.guru maintains the largest searchable directory of OpenAPI/Swagger definitions for public APIs, normalizing specs pulled from thousands of providers into one browsable catalogue. Its own machine-readable endpoint (api.apis.guru/v2) needs no key or account and returns the full listing plus individual OpenAPI documents as JSON or YAML. The project is open-source and entirely free, run as a community effort rather than a paid product.

Beeceptor lets you spin up a mock REST endpoint at a custom subdomain in seconds, define rule-based JSON, XML, plain-text, or binary responses through a no-code rule builder, and inspect the live requests hitting it in real time. It also doubles as an HTTP proxy for intercepting and rewriting responses from a real backend during development. The free tier needs no signup or API key — 50 requests/day per endpoint with up to 3 rules — with paid plans from $10/month unlocking private endpoints, higher volume, and CI/CD integration.