Todo Lists.
Todoist API is a free Documents & Productivity API that requires OAuth authentication, is served over HTTPS and has unconfirmed CORS support.
The central hub for the Todoist developer platform: REST API, MCP server, CLI, SDKs, and webhooks — built for developers and AI agents.
Details from developer.todoist.com.

Unified API suite · now live
Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
Performs image upscaling by adding detail to images through multiple super-resolution algorithms
The Todoist API is provided by Todoist Developers (developer.todoist.com). The central hub for the Todoist developer platform: REST API, MCP server, CLI, SDKs, and webhooks — built for developers and AI agents.
Yes. The Todoist API is listed in the Documents & Productivity category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
Yes. The Todoist API uses OAuth authentication, so you need to register for credentials before making requests.
CORS support for the Todoist API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The Todoist API is served over HTTPS, so it's safe to use in production.