# Free open source APIs

Page: https://free-web-services.com/free-apis/open-source/

These free APIs are open source: besides the public service, the code is available, so you can read how it works and, if the public server is not enough, run your own copy without limits.

| Service | Category | API key | Formats | Free use |
|---|---|---|---|---|
| [Pollinations.ai](https://free-web-services.com/web-services/ai/pollinations-ai.md) | Artificial intelligence | Not needed | - | Free, works without a key or sign-up; registering gives higher limits. |
| [bible-api.com](https://free-web-services.com/web-services/documentation/bible-api-com.md) | Books and research | Not needed | JSON | Free and open source, no key needed. |
| [Gutendex](https://free-web-services.com/web-services/documentation/gutendex.md) | Books and research | Not needed | JSON | Free and open source, no key needed; it is a community service without uptime guarantee, so you can host it yourself for heavy use. |
| [PoetryDB](https://free-web-services.com/web-services/documentation/poetrydb.md) | Books and research | Not needed | JSON | Free and open source, no key needed. |
| [ntfy](https://free-web-services.com/web-services/communication/ntfy.md) | Communication | - | - | Free on ntfy.sh, and open source so you can host it yourself. |
| [Frankfurter](https://free-web-services.com/web-services/unit-convertors/frankfurter.md) | Currency and finance | Not needed | JSON | Free, no key needed and no usage limits. |
| [Free Currency Exchange Rates API (fawazahmed0)](https://free-web-services.com/web-services/unit-convertors/free-currency-exchange-rates-api-fawazahmed0.md) | Currency and finance | Not needed | JSON | Free. |
| [country.is](https://free-web-services.com/web-services/geo/ip-to-location/country-is.md) | IP to location APIs | Not needed | JSON | Free and open source, no key needed. |
| [ipify](https://free-web-services.com/web-services/geo/ip-to-location/ipify.md) | IP to location APIs | Not needed | JSON | Free and open source, no key and no usage limit. |
| [Nager.Date public holidays](https://free-web-services.com/web-services/geo/location-info/nager-date-public-holidays.md) | Location Information | Not needed | JSON | Free and open source, no key needed. |
| [OpenRouteService](https://free-web-services.com/web-services/geo/location-info/openrouteservice.md) | Location Information | Needed, free | JSON | Free plan with a free API key and daily limits per service; open source, so you can also host it yourself. |
| [Photon](https://free-web-services.com/web-services/geo/location-info/photon.md) | Location Information | - | JSON | The public server at photon.komoot.io is free for fair use; for heavy use you can host Photon yourself, as it is open source. |
| [Postcodes.io](https://free-web-services.com/web-services/geo/location-info/postcodes-io.md) | Location Information | Not needed | JSON | - |
| [Open-Meteo](https://free-web-services.com/web-services/geo/weather/open-meteo.md) | Weather forecasts | Not needed | JSON | Free for non-commercial use; commercial use needs a paid plan. |
| [wttr.in](https://free-web-services.com/web-services/geo/weather/wttr-in.md) | Weather forecasts | Not needed | - | Free and open source, no key needed. |
| [Iconify API](https://free-web-services.com/web-services/graphics/iconify-api.md) | Graphics | Not needed | - | Free, no key needed; the server is open source and can be self-hosted. |
| [Kroki](https://free-web-services.com/web-services/graphics/charts/kroki.md) | Chart APIs | - | - | Free public server; open source, so you can also run it yourself. |
| [QuickChart](https://free-web-services.com/web-services/graphics/charts/quickchart.md) | Chart APIs | - | - | Free plan with a monthly limit; paid plans for more charts. |
| [DiceBear avatars](https://free-web-services.com/web-services/graphics/images/dicebear-avatars.md) | Image and photo | Not needed | XML | Free and open source, no key needed. |
| [Free Dictionary API](https://free-web-services.com/web-services/language/free-dictionary-api.md) | Language and text | Not needed | JSON | Free and open source, no key needed. |
| [Spaceflight News API](https://free-web-services.com/web-services/news/spaceflight-news-api.md) | News feeds and APIs | Not needed | JSON | Free and open source, no key needed. |
| [Dog CEO Dog API](https://free-web-services.com/web-services/other/dog-ceo-dog-api.md) | Other | Not needed | JSON | Free and open source, no key needed. |
| [Open Brewery DB](https://free-web-services.com/web-services/other/open-brewery-db.md) | Other | Not needed | JSON | Free and open source, no key needed. |
| [PokéAPI](https://free-web-services.com/web-services/other/pokeapi.md) | Other | Not needed | JSON | Free and open source, no key needed. |
| [Nu HTML Checker (W3C)](https://free-web-services.com/web-services/web-development/validators/nu-html-checker-w3c.md) | Data validators | - | - | Free and open source; for heavy use, run your own copy of the checker. |
| [OpenIBAN](https://free-web-services.com/web-services/web-development/validators/openiban.md) | Data validators | Not needed | JSON | Free and open source, no key needed. |
| [httpbin](https://free-web-services.com/web-services/web-development/testing/httpbin.md) | Testing and mock data | Not needed | JSON | Free and open source, no key needed; you can also run it yourself in Docker. |