GitHub

GitHub's REST API is exceptionally comprehensive and well-documented, offering over 200 endpoints covering repositories, pull requests, issues, actions, and more.

Authentication supports OAuth2, Personal Access Tokens, and GitHub Apps with fine-grained permissions. Rate limits are generous (5,000/hour authenticated, 60/hour unauthenticated). The Octokit SDK provides excellent client libraries across all major languages. GraphQL v4 API is also available for flexible queries. Webhooks enable real-time event notifications. The API powers integrations, CI/CD, automation, and custom tooling. Developer experience is outstanding with interactive documentation, API versioning, and extensive community support.

It's ideal for development tools, project management integrations, and automation workflows, with a strong free tier for individual developers.