Every calendar, always telling the same story
Pick the calendars that should mirror each other and CalSync handles the rest — new events, reschedules, cancellations and deletions, in whichever direction you asked for.
- One-way, two-way and many-to-many syncs
- Updates land in seconds, not hours
- Copies are tagged, so nothing ever loops
- Works across accounts and organisations
Work calendar
dana@acme.com
Consulting
d.reed@studio.io
Personal
dana@icloud.com
How a sync actually works
A sync reads events from your source calendars inside a window you choose, then creates a matching event on each target. Every copy is recorded with a fingerprint of its source, so the next pass knows exactly what to update, what to leave alone and what to remove.
- Fingerprints mean unchanged events are skipped entirely
- Moved or shortened meetings are updated in place
- Deleting the original removes every copy it produced
No loops, ever
Mirrored events carry a private marker and are tracked in our database, so they are never picked up as a source. That means you can safely put the same calendar in as many syncs as you like without events multiplying.
- Markers are stored in provider-private fields, invisible to guests
- A calendar can be source and target at the same time
- Deleting a sync offers to clean up every copy it made
Choose your window
There is rarely a reason to sync three years of history. Set how far back and how far forward each sync should look, and CalSync stays inside that window — faster runs and far fewer API calls.
- Defaults to 7 days back and 90 days ahead
- Anything from a day to two years
Filters that match real life
Skip events you declined, keep private appointments out entirely, decide whether all-day events count, and add a reminder to copies if you want the nudge.
- Skip declined invitations
- Skip events marked private
- Include or exclude all-day events
- Events marked free never block your time
Good to know
- How fast is real time?
- Google and Outlook support change notifications, so most updates appear within a few seconds. A scheduled pass runs on your chosen interval as a safety net. iCloud has no push channel, so it polls — expect up to ten minutes there.
- What happens if a provider is down?
- The run is marked failed and retried with a backoff. Nothing is deleted on a failed read, so a provider outage can never wipe your mirrored events.
- Can I sync a calendar someone shared with me?
- Yes, as a source. Writing into a shared calendar needs edit permission — CalSync marks read-only calendars so you cannot pick them as a target by mistake.
Keep exploring
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