Sync every calendar.
Never double-book again.
CalSync keeps Outlook, iCloud and Google calendars in sync in real time, shares booking links people actually enjoy using, and puts every calendar in one clean view.
No card, no trial, no plans — every feature, for everyone
This week
No event data stored
We keep timings, never content.
Live in under 3 minutes
Connect, pick calendars, done.
OAuth-only access
We never see a password.
Works with the tools your day already runs on
Sync several calendars and simplify booking
Stop reconciling calendars by hand. Set the rules once, and CalSync keeps every calendar honest — without leaking what your meetings are about.
Real-time updates
Changes land in every connected calendar within seconds — reschedules, cancellations and new invites included.
Multi-way syncs
One-way, two-way, or many-to-many. Configure each direction independently.
Privacy modes
Copy a plain busy block, just the title, or the full event. Per sync.
Booking links
Share a link, let people pick a slot. Availability is checked against every calendar you connect.
Unified calendar
Every calendar, one view. Create, edit and join meetings without switching tabs.
Built for teams
Round-robin and collective links, shared availability, org-wide admin. No seat counting.
Keep any number of calendars in step
Pick the calendars that should mirror each other and CalSync handles the rest — creates, updates, moves and deletions, in every direction you asked for. Copies are tagged, so a calendar can take part in as many syncs as you need without ever looping.
- One-way, two-way or many-to-many
- Reschedules and cancellations follow automatically
- Choose how far back and forward to sync
Work calendar
dana@acme.com
Consulting
d.reed@studio.io
Personal
dana@icloud.com
Your client never learns your dentist appointment
Each sync decides how much detail travels. Copy a neutral busy block into your work calendar, share full details with your own accounts, and keep confidential meetings out of the picture entirely.
- Busy blocker, title only, or full details
- Skip private, declined and all-day events
- Rename the blocker to whatever you like
Source event
Board meeting — Q3 numbers
Thu 14:00–15:30 · Zoom · 6 guests · confidential agenda
Busy
Busy blockerNo title. No guests. No details.
Board meeting
Title onlyTitle copied, everything else hidden.
Board meeting
Full detailsZoom · 6 guests · agenda in description
Share a link. Skip the back-and-forth.
Booking pages that check every calendar you connect before offering a slot, respect buffers and notice periods, and add the meeting to the right calendar the moment someone books.
- One-on-one, collective and round-robin links
- Buffers, minimum notice and daily caps
- Automatic Meet, Zoom or Teams details
Intro call with Dana
calsync.dev/dana/intro
Mon
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Tue
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Wed
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Thu, 9 Oct
Every calendar in one place
Work, side project, family — one timeline, colour-coded by source. Create and edit events, join calls and answer invitations without hopping between four tabs.
- Day, week and month views
- Filter by calendar or account
- Copies are marked so you always know what is real
Thursday, 9 October
3 calendarsGym
Personal
Design review
Work
Client workshop
Consulting
Pick up kids
Personal
We ask for the minimum and store even less
CalSync connects over OAuth, requests calendar scopes only, and writes nothing about your meetings to disk. If that is still too much trust to hand over, run the whole thing yourself.
No event content stored
We persist the mapping between a source event and its copy, plus start and end times. Titles, notes, attendees and attachments stay on your provider.
OAuth only, revocable
You grant calendar access through Google or Microsoft and can revoke it at any moment. iCloud uses an app-specific password you generate and can delete.
Least-privilege scopes
Read and write to calendars. Nothing else — no mail, no files, no contacts, no drive.
The alternatives all leak something
Copying events by hand costs you time and still misses reschedules. Subscribing to an .ics feed is read-only, delayed by hours and invisible to colleagues booking your time.
| CalSync | Manual copying | .ics subscription | |
|---|---|---|---|
| Real-time, multi-way sync | — | — | |
| Keeps event details private | — | — | |
| Updates and deletions propagate | — | delayed | |
| Booking links with live availability | — | — | |
| Works across organisations | — | ||
| Free, with no feature held back | |||
| You can host it yourself |
Your calendars, connected to everything
Calendar providers, video platforms, AI assistants through our MCP server, and 9,000+ more tools through Zapier.
Read the code that touches your calendar
Every sync rule, every API call, every byte we store is in the open. CalSync is free either way: use the hosted instance, or deploy it on your own infrastructure — same code, same features, no artificial limits.
# up and running in four commands
git clone github.com/calsync/calsync
npm install
npm run setup
npm run dev
✓ ready on http://localhost:3000
Frequently asked questions
Put your calendars back in sync today
Connect your first two calendars in under three minutes. Free forever, every feature included.