Your calendars don't talk to each other. Let's fix that.
CalendarPipe is a programmable calendar sync service for Google Calendar, Outlook, and Apple Calendar. It copies events between them through pipes, and each pipe's rule decides which ones cross over and what they say when they arrive.
- Free forever for 2 accounts
- $4/month for unlimited
- No credit card
Pediatrician
Thu 3 – 4 PM
Personal commitment
Thu 3 – 4 PM
Start from a situation
Most people arrive with one specific problem. Here are the common ones, already solved.
Shared family calendar
Household duties block your working hours. Your evening commitments show up at home. Nobody has to ask.
See the setupContracting across two companies
Two employers, two calendars, one you. Stop double-booking without leaking either client’s business.
See the setupConference networking meetings
Your matchmaking app pairs two attendees. The meeting lands in both their calendars, at two companies that never connected anything.
See the setupClient booking link
One link clients can book. Behind it, the hours that are genuinely free — your personal calendar included, and nobody sees what is on it.
See the setupWrite a rule, watch it run
Build a rule visually and see the results instantly
The same rule, on your real calendars. Free forever for 2 connected accounts, no card.
Locked-down work calendar? Send an invite instead.
Your pipe sends each event to your work calendar as a normal invitation. Nothing to connect, no IT approval, and changes update in place. It also decides what shows up there: “Personal commitment”, not “Dentist”.
Dentist
Thu 2 – 3 PM
Transform to "Personal commitment". Deliver as invitation.
Personal commitment
Thu 2 – 3 PM
When IT blocks third-party OAuth, invitation-based delivery still gets through — because it's just email.
You decide what counts as busy
Share a link and people book your free time. Which events take it off the table is a rule you write — the same kind that drives your sync.
Client standup
You accepted it.
Team offsite — planning
An invitation you never answered.
Dana’s birthday
An all-day entry, not a commitment.
School pickup
On your personal calendar. Blocked, and never named.
The booker needs no account.
They pick a time, confirm their email, and a real calendar invitation arrives. Nothing to install, nothing to sign up for.
Only free time is ever shown.
The page publishes openings, not your schedule. A blocked hour is missing from the list rather than greyed out in it.
A calendar it can’t read offers nothing.
An expired connection shows no availability rather than guessing it is empty. The page never offers time it cannot verify is free.
Give your AI agent a calendar
An agent that schedules meetings should not need access to your users' calendars. Give it a hosted one of its own: an API key instead of an OAuth dance, and real email invitations attendees accept in whatever calendar they already use.
201 · a calendar with its own email address
201 · invitation sent to every attendee
204 · cancellation sent
Pro plan · Agent skills · llms.txt · Webhooks · OpenAPI 3.1
Your data stays yours
Built by two engineers in Prague who would rather not hold your calendar. Three decisions keep it that way.
We never see your password.
You authenticate directly with Google or Microsoft. We get a scoped token, never your credentials.
We don’t store your events.
Events are fetched, piped through your rules, and synced to the target. We never keep a copy of your calendar data.
Rules run in a sandbox.
Your code executes in an isolated environment with zero network access. Your data can’t leak even if you tried.
Free for two accounts. $4 a month for everything.
Most calendar sync tools charge $10 or more a month. We priced this one so you don't have to think about it.
Free
One sync between two accounts
No credit card. Free forever.
Pro
Every calendar you have
$40 billed annually
Card required. Cancel anytime before day 14.
Business
For teams and batch accounts
Manually managed. No self-serve checkout.
Frequently asked questions
Google and Microsoft connect over OAuth (we never see your password); Apple and other CalDAV servers use an app password you can revoke. We encrypt all tokens and passwords with AES-256-GCM, run rules in a sandboxed environment with zero network access, and never store your calendar events on our servers. All traffic is TLS-encrypted.
A rule is the logic a pipe applies, and there are four ways to write one, all producing the same result. Most people start with the visual builder. You can also describe what you want in plain English and let AI write it, start from a template, or write TypeScript in the code editor.
Google Calendar™, Microsoft Outlook™ (including Office 365™ and Outlook.com™), Apple Calendar™, and any CalDAV server — Fastmail, Infomaniak, Nextcloud and others. ICS feeds work as a source too.
Yes. Create multiple pipes to connect any combination of calendars. Calendars are never the limit: every calendar in an account you connect is yours to sync, on any plan. Free covers 2 connected accounts and 1 pipe; Pro makes both unlimited.
Every 15 minutes on Free, every 5 minutes on Pro. New events, updates, and cancellations all propagate automatically.
Yes. Pro has a 14-day free trial with full feature access. We do collect a card upfront, but you won’t be charged until day 14, and you can cancel anytime in between with two clicks. Not ready to commit? The free plan has no expiration date.
Yes. There are no long-term contracts. Cancel from your dashboard in two clicks; disconnect your calendar accounts and we lose access immediately.
Yes. A booking page gives you a link to share; visitors see only your free time, pick a slot, and get a real calendar invitation by email — no account, nothing to install. What counts as busy is up to you: each calendar you add can carry a rule, so a pending invitation or an all-day birthday need not block. Free includes one booking page reading one calendar, 14 days ahead; Pro is unlimited. Rescheduling is included; custom questions and embeds are still ahead.
Agentic Hosted Calendars are programmable calendars created via API. They let AI agents and automations manage their own calendars — creating events, resolving conflicts, and delivering schedules to attendees via email invitation. No OAuth connection is required on the recipient side.
Yes. CalendarPipe provides a REST API and installable agent skills for tools like Claude and Cursor. Your agent can spin up its own calendar, create events, and deliver real invitations to any inbox — all via API.
Instead of requiring OAuth access to the target calendar, CalendarPipe delivers synced events as standard email invitations (iCalendar/.ics). The recipient accepts the invite and the event appears in their calendar — no app installation or sign-up required.
Yes. Full API docs, agent skills for AI tools, and an llms.txt file so AI agents can find the API on their own.
Your calendars won't fix themselves
Pick two calendars, write one rule, and stop thinking about it. Free forever, no card.
Indie-built in Prague by two engineers. Meet them