Explore free Open Source Projects APIs available for developers. Browse our collection of public APIs in the Open Source Projects category, each verified and documented for easy integration into your projects.
Last verified: November 12, 2026
| Name | Description | Auth | HTTPS | CORS | Uptime (30 days) |
|---|---|---|---|---|---|
| Countly | Countly web analytics | none | Yes | unknown | 80.0% (5 checks) |
| Creative Commons Catalog | Search among openly licensed and public domain works | oauth | Yes | yes | 100% (5 checks) |
| Datamuse | Word-finding query engine | none | Yes | unknown | 100% (5 checks) |
| Drupal.org | Drupal.org | none | Yes | unknown | 100% (5 checks) |
| Evil Insult Generator | Evil Insults | none | Yes | yes | 100% (5 checks) |
| GitHub ReadMe Stats | Add dynamically generated statistics to your GitHub profile ReadMe | none | Yes | yes | 100% (5 checks) |
| Libraries.io | Metadata, dependencies and release history for open-source packages across 30+ managers | apikey | Yes | yes | 100% (5 checks) |
| Neuronto ARD Registry | Search index of MCP servers, agents and APIs, with the tools each server actually exposes | none | Yes | yes | 100% (5 checks) |
| OpenSERP Cloud | Managed SERP API for Google, Bing, Yandex and more. Get live browser-rendered search results through a single API with data extraction | apikey | Yes | no | 100% (5 checks) |
6 of these APIs require no authentication — you can start making requests immediately without signing up for an account. Just pick one from the table above, check its documentation, and send your first request.
2 APIs in this category require a free API key. This usually means creating a free account on the provider's website and copying your key from the dashboard. The process typically takes less than a minute.
Not sure where to start? Check the uptime column: it shows how often each API's documentation responded to our daily checks over the last 30 days, and the dot shows whether it responded at the latest check. For browser-based projects, check that the API supports CORS.
Yes, all APIs listed on API Bouncer have a free tier. Some are completely open (no sign-up needed), while others require a free account to get an API key. Free tiers typically have rate limits — check each API's documentation for specifics.
It depends on your needs. Consider: Do you need authentication or prefer no-auth? Does your project need CORS support for browser access? How many requests will you make? Start with a no-auth API to prototype quickly, then switch to a more feature-rich option if needed.
We run periodic health checks on all listed APIs. The "Status" column shows whether each API was responding at our last check. APIs marked as "alive" were recently verified. You can also test any API yourself using curl or our guides on testing APIs.
Most free APIs allow commercial use, but terms vary by provider. Always check the specific API's terms of service. Some APIs have separate free and commercial tiers with different rate limits.
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