Open Source APIs

Open source project data

8 APIs in this category · last checked 2 October 2026
8
APIs listed
5
need no API key (63%)
0
CORS enabled (0%)
8
HTTPS (100%)

This directory lists 8 open source APIs. Use the filters below to narrow by authentication, HTTPS support and CORS. Every entry shows whether it needs authentication, serves over HTTPS and allows cross-origin requests, so you can pick one that fits your stack before you read a single doc page.

Showing 8 of 8 APIs

Drupal.org

Drupal.org exposes read only REST access to modules, themes, issues, and security advisories, with no key required and a 50 record limit per query.

Auth: No HTTPS CORS: Unknown

Countly

Countly is a self-hosted open source analytics and engagement platform; its server write API logs events and sessions using an app key, with enterprise plugins for funnels and AB testing.

Auth: apiKey HTTPS CORS: Unknown

Datamuse

Datamuse returns words matching meaning, sound, or spelling for autocomplete and word games, free without a key up to 100,000 requests per day, though a key becomes mandatory from 2027.

Auth: No HTTPS CORS: Unknown

Metabase

Metabase is a self-hosted open source business intelligence tool whose REST API manages dashboards, questions, and data exports, authenticated with a session token or an admin issued API key.

Auth: apiKey HTTPS CORS: Unknown

Shields

Shields.io renders SVG and PNG badges showing build status, downloads, or custom text for README files, free with no key required, and offers a Docker image for self-hosting at scale.

Auth: No HTTPS CORS: Unknown

Evil Insult Generator

Evil Insult Generator returns a random insult in English, Dutch, or German as text, XML, or JSON from a single endpoint, with no key needed and no documented rate limit.

Auth: No HTTPS CORS: Unknown

Openverse

Openverse, formerly the Creative Commons Catalog, searches hundreds of millions of openly licensed and public domain images and audio tracks, free without a key though OAuth raises rate limits.

Auth: OAuth HTTPS CORS: Unknown

GitHub ReadMe Stats

GitHub ReadMe Stats generates dynamic SVG cards showing commit, star, and language stats for a README, free on a shared public instance that warns it can be unreliable under traffic spikes.

Auth: No HTTPS CORS: Unknown

Best Open Source APIs for Developers

An open source API allows developers to query repository data, track project health metrics, access contributor information, and monitor package ecosystems across GitHub, GitLab, and other code hosting platforms.

Datamuse and Shields.io are the easiest wins here: no key, generous free limits, and they solve a narrow problem well, word lookups for autocomplete and badges for a repo README. Openverse (formerly the Creative Commons Catalog) is the pick for sourcing openly licensed images and audio, though its biggest pitfall is licensing: each result carries its own license and attribution terms that your app must track, not a blanket free-to-use grant.

Countly and Metabase suit teams who want to self-host analytics or BI rather than lean on a SaaS vendor, trading setup effort for full data ownership. GitHub ReadMe Stats is handy for a quick profile card, but its public demo instance is explicitly best-effort, so anything production-facing should run a self-hosted copy instead.

What to check before you pick one

  • Rate limits: GitHub's unauthenticated limit is 60 requests per hour; always authenticate to get the higher 5,000 request limit for production apps.
  • GraphQL support: GitHub and GitLab both offer GraphQL APIs that let you fetch exactly the fields you need in a single request.
  • Webhook events: Subscribe to repository events (push, PR, issue) to build real-time integrations without polling.

Frequently Asked Questions

What are open source APIs?

Open source APIs provide programmatic access to repository metadata, contributor statistics, issue trackers, package registries, and code hosting platform data for tracking and analyzing open source ecosystems.

Is the GitHub API free?

Yes. GitHub's REST and GraphQL APIs are free for public data. Unauthenticated requests are limited to 60 per hour; with a personal access token the limit increases to 5,000 per hour.

How do I track GitHub repository stars and forks via API?

Query the GitHub REST API endpoint GET /repos/{owner}/{repo} to retrieve star count, fork count, open issues, and other repository metadata in JSON format.

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