Trello

Trello REST API enables programmatic access to boards, lists, cards, members, and webhooks for project management automation.

Uses delegated OAuth 1.0a authentication with API key and token combination - no usernames or passwords stored. The API covers complete CRUD operations for all Trello resources including boards, lists, cards, checklists, labels, and attachments. Rate limits are 300 requests per 10 seconds per API key and 100 per 10 seconds per token. Webhooks support real-time updates when models change. Official JavaScript client library (client.js) and community SDKs available for Python, PHP, and Node.js. Maximum 1000 results per query with pagination via before/since parameters.

Free tier includes generous limits across all plans. Ideal for task automation, custom project management tools, and team collaboration workflows with intuitive REST architecture.