Never double-booked again.
Tandem mirrors busy time between every calendar you own and puts a single booking link in front of all of them. Changes propagate in seconds, and you can see exactly what synced and why.
Free forever for 2 calendars
Three calendars, one honest answer
Every busy block from every connected calendar becomes a block on the others, and the same picture drives your booking page.
One slot free out of five. Nobody can book over the other four, whichever calendar they live on.
What makes Tandem different
We built this after paying for a competitor that charged per one-way connection and silently stopped syncing for a week.
Pay per account, not per connection
Three calendars is one sync group, not six one-way connections you have to configure and pay for separately. Add an account, put it in a group, done.
No calendar caps on Pro
Connect your work Google account, your personal one, the consulting Outlook account and the shared team calendar. Pro is $9/mo whether that's four calendars or forty.
A free tier that actually works
Two connected accounts, one sync group, one booking page, forever. Not a 14-day trial with a credit card form in front of it.
A sync log you can read
Every mirrored block, update and deletion is recorded with a timestamp, the source event and the reason. When something looks wrong you can see what happened instead of guessing.
Webhook-driven, not polling
Google and Microsoft push change notifications to Tandem the moment an event moves. Typical propagation is under a minute, not the 15-minute poll cycle you're used to.
Privacy controls per group
Choose Busy only, Title only, or Full details for each sync group. Your therapy appointment can land on the work calendar as a nameless block.
How it works
Setup takes about three minutes and you never have to think about it again.
Connect your calendars
Sign in with Google or Microsoft and authorize the accounts you want Tandem to watch. Read and write scope only on the calendars you pick.
Put them in a sync group
Drop two or more calendars into a group and pick a privacy mode. Every busy block in the group is mirrored to the others as a Tandem-owned event.
Share one booking link
Your booking page reads every calendar in the group, so people can only pick slots that are genuinely free across all of them.
Tandem vs. the alternatives
Compared against the published plans of CalendarBridge and OneCal.
| Feature | Tandem | CalendarBridge | OneCal |
|---|---|---|---|
| Free tier | 2 accounts, forever | None | None |
| Pricing unit | Per connected account | Per sync connection | Per calendar |
| Calendar limit on top plan | Unlimited | Capped by tier | Capped by tier |
| Visible sync activity log | Yes, 90 days on Pro | No | No |
| Booking pages included | Yes, unlimited on Pro | Add-on | Limited |
Questions people ask first
Does it copy my meeting details?
Only if you ask it to. Each sync group has a privacy mode. On Busy only, the mirrored event is a blank block titled "Busy" with no description, location or attendees. On Title only, the title comes across and nothing else. Full details copies title, description and location. Tandem never copies attendee lists or conference links.
What happens if I disconnect?
Removing an account deletes its stored OAuth tokens immediately and queues a cleanup job that removes every event Tandem created on that calendar. You get your calendar back the way it was, and the deletions show up in your activity log so you can confirm it happened.
How fast is sync?
Google and Microsoft send Tandem a webhook when a calendar changes, and the change is processed on a queue. Most mirrored blocks appear on the other calendars in under a minute. Pro accounts are processed ahead of free accounts when the queue is busy.
Which calendars are supported?
Google Calendar, including Google Workspace accounts, and Microsoft 365 and Outlook.com. Any calendar those accounts can see and write to can be part of a sync group, including shared and delegated calendars.
Can I cancel anytime?
Yes. Cancel from billing and Pro stays active until the end of the period you paid for, then the account drops to the free plan. Nothing is deleted when you downgrade, but sync groups and booking pages beyond the free limits are paused until you're back under them.
Connect two calendars and stop worrying about the third meeting
The free plan covers two accounts, a sync group and a booking page. Upgrade when you run out of calendars, not when a trial ends.