Free Open Source Projects APIs

Countly is an open-source product analytics platform, and its REST API lets you query event data, session metrics, user counts, and custom dashboards you have set up in your Countly instance.

Datamuse is a free word-finding API that helps you discover words by meaning, sound, spelling, and context — no API key needed.

The Drupal.org API gives you programmatic access to information about Drupal modules, projects, users, and releases hosted on drupal.org.

The Evil Insult Generator API returns randomly generated humorous (fictional) insults in multiple languages — no API key required.

The GitHub Contribution Chart Generator API creates a visual representation of any GitHub user's contribution activity over the past year.

GitHub ReadMe Stats is an open-source API that generates dynamic SVG cards showing your GitHub statistics — repos, stars, commits, languages, and more.

Metabase is an open-source business intelligence tool with a REST API that lets you query your databases, manage dashboards, and export data programmatically.

Shields.io is a free API that generates SVG and PNG badge images for use in README files and documentation — showing things like build status, version numbers, license, and download counts.