Frequently asked questions

Public APIs is a free, searchable directory of 2,166 public APIs across 51 categories, from weather and finance to animals and machine learning. Every listing shows whether the API needs authentication, supports HTTPS and allows CORS, with a link to its documentation. The list is curated by the open-source public-apis community and maintained with APILayer.

Yes. Every API in the directory is free to use or has a free tier. Some require you to sign up for an API key, and paid plans may unlock higher rate limits, but you can start building with all of them at no cost.

1,038 of the 2,166 APIs need no authentication at all, so you can call them immediately without signing up. Use the "No auth" filter on any category page, or browse all of them at /search?auth=none.

CORS (Cross-Origin Resource Sharing) decides whether a browser lets JavaScript on your website call the API directly. If CORS is enabled, you can fetch from front-end code; if not, call the API from a server or serverless function instead. 878 APIs in the directory are confirmed to support CORS.

Start from a category, then filter by authentication, HTTPS and CORS to match your stack. Prefer APIs with HTTPS (required for production), check the documentation for rate limits and terms of use, and pick a no-auth API if you're prototyping.

Open a pull request on the public-apis GitHub repository (https://github.com/public-apis/public-apis) that adds your API to the right category table, following the contribution guide (https://github.com/public-apis/public-apis/blob/master/CONTRIBUTING.md). Once it's merged, it appears here on the next data sync.

Yes. GET /api/apis returns the catalog as JSON and accepts the same filters as search: q, category, auth, https, cors and page. It needs no key and is handy for building your own tools on top of the list.

MCP (Model Context Protocol) servers let AI agents such as Claude, Cursor or VS Code call APIs as tools. The directory lists 22 MCP servers with their transport (stdio or HTTP), authentication and install links.

The list comes from the community-curated public-apis project on GitHub, one of the most-starred repository on the platform, and is maintained together with APILayer (https://apilayer.com/), which offers a unified suite of production APIs with one account and one API key.