APIs.guru vs CORS Proxy

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.

CORS Proxy is a small open-source Node.js server (54 GitHub stars) that forwards a POST request's urlToGet body param to the target URL server-side and relays the response back with permissive CORS headers, sidestepping browser CORS errors for GET-able resources. It is a deploy-it-yourself utility, not a hosted service — the README's old Heroku demo link is dead since Heroku retired free dynos in 2022, so it only works once cloned and deployed to your own host.