Contact fatcalendar

How to reach fatcalendar for feedback, corrections to festival dates, API questions or security reports.

Get in touch

General, feedback and corrections: hello@fatcalendar.com
Security reports: security@fatcalendar.com (see security.txt)
API and MCP questions: read API docs and MCP docs first, then email us.

Reporting a wrong date

Please include the tradition and variant, language, place (or latitude, longitude and time zone), the date shown, the date you expected and the almanac or authority you are comparing with. Festival dates can legitimately differ between almanacs; we will explain the rule used (every festival carries a rule field) or fix real bugs.

Response time

This is a small independent project. We aim to reply within a few working days.

For machines

Agents can read AGENTS.md, llms.txt and the OpenAPI document.