sync.day

sync.day helps groups find a mutually available time. An organizer creates an activity, sets the dates, hours, duration, and start-time intervals, then shares a link for participants to mark when they can attend.

The page ranks possible start times by the number of available participants and lets the organizer confirm a time. It works in mobile and desktop browsers without an account or app installation, and is free to use.

sync.day also provides a public MCP server that can connect to Claude, Cursor, ChatGPT, or another agent to create activities, enter availability, and view rankings. Activity links are unlisted and randomly generated, but anyone with a link can access the activity.