Sync your calendars without sharing the details.

You keep two calendars so work and life don’t bleed together. Then someone tries to book you at 3pm, and the calendar they’re looking at says you’re free, because the meeting is on the other one. So you double-book. Or you share the whole calendar to fix that, and now your coworkers can read “Performance review, Thursday.”

buoycal reads your source calendars and writes blocks to your destinations. A meeting titled “Acquisition sync — Project Falcon” lands on the other side as a block that says Busy: the right time, nothing else.

It works with Google Calendar, Microsoft 365 and Outlook, and any standard CalDAV server, like iCloud, Fastmail, Nextcloud, or your own. One-way, both ways, many-to-one: you decide which calendars feed which.

You decide which events count, too. Plain when/then rules: when an event is all-day, skip it; when you declined, no block. Only the times that matter are written.

Self-hosted, your event titles never leave your machine. Hosted, a title is held in memory only long enough to compute the block. It is never written to disk, logged, or sent on. What we store is a time and the word “Busy”. If you’d rather it never touch our servers, buoycal is open source; run it yourself.