Free APIs
Free Developer tools APIs
| API | Free tier | Auth | Docs |
|---|---|---|---|
| GitHub REST API Repos, issues, pull requests and users Catch: Token needed for higher limits and private data | Authenticated: 5,000 requests/hour (unauthenticated is lower) | No key | docs |
| npm Registry API Package metadata and download counts Catch: Rate limits apply to downloads API | Free, no key | No key | docs |
| PyPI JSON API Package metadata and release files Catch: Cached; be gentle | Free, no key | No key | docs |
| Docker Hub API Image metadata, tags and repositories Catch: Pull rate limits apply to anonymous image pulls | Free; public data readable | No key | docs |
| Stack Exchange API Stack Overflow questions, answers and users Catch: Quota is per IP/app; honor backoff | Free; default quota 10,000 requests/day with a key | API key | docs |
| Forem (DEV) API DEV articles, comments and users Catch: Public reads need no key | Free; key for writes | API key | docs |
| Libraries.io API Open source package and dependency data Catch: 60 requests/minute | Free key; 60 requests/minute | API key | docs |
| crates.io API Rust crate metadata Catch: Crawl policy: 1 request/second, set User-Agent | Free, no key; 1 request/second | No key | docs |
| Microlink Link previews, screenshots and metadata Catch: Free tier rate limited | Free: 50 requests/day | No key | docs |
| Nager.Date Public holidays for 100+ countries Catch: Community-run | Free, no key | No key | docs |
| Calendarific Holidays and observances worldwide Catch: Free plan non-commercial | Free plan: 500 requests/month | API key | docs |
| API Ninjas Dozens of small utility APIs (nutrition, jokes, validation) Catch: Free tier limits premium endpoints | Free tier with monthly call limit | API key | docs |
| SerpApi Google and other search results as JSON Catch: Free plan not for commercial use | Free plan: 250 searches/month | API key | docs |
FAQ
What is the best free developer tools API?+
GitHub REST API, npm Registry API, PyPI JSON API are good places to start. Compare the free tiers and catches in the table; they differ mostly in limits and whether commercial use is allowed.
Is there a developer tools API without an API key?+
Yes: GitHub REST API, npm Registry API, PyPI JSON API, Docker Hub API, crates.io API work without a key.
More free APIs: Weather · Maps & geocoding · Finance & crypto · Currency exchange · AI & ML · Email & messaging · IP & geolocation · News & social · Sports · Movies, TV & anime · Music · Books & reference · Space & science · Government & open data · Translation & language · Images & media · Fake data & testing · Food & recipes · Transportation · Health · Security · Games & fun