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Tool comparison

Kalender Sync vs. CalendarPipe – sync by code or by click?

For developers, CalendarPipe is honestly really cool: sync rules as TypeScript, an open API with webhooks and „agent skills" for AI assistants – for $4 a month. We won't make it easy on ourselves: here's where CalendarPipe shines, and when Kalender Sync is the better pick for everyone who doesn't want to write code.

Try free for 7 days See the CalendarPipe view

Background

What can CalendarPipe do?

CalendarPipe is an indie tool by the two developers Jakub Beneš and Tomáš Růžička from Prague. It synchronises Google Calendar, Outlook/Microsoft 365, Apple Calendar as well as iCal feeds through so-called „pipes" – rules that filter, transform and transfer events. You build rules visually, write them directly as TypeScript/JavaScript (executed in a sandbox with no network access) or have them generated by AI. On top of that come a public REST API with an OpenAPI 3.1 spec, webhooks and installable „agent skills" for AI assistants such as Claude or Cursor. On privacy, CalendarPipe promises „We don't store your events": events are processed and passed through, not retained. The free plan covers 2 calendar connections, 1 sync rule, a 15-minute interval and a 14-day sync window; Pro costs $4/month (or $40/year) with unlimited connections, a 5-minute interval, a 90-day window, AI rules, API access and email invitation delivery – with a 14-day trial that requires a card up front.

Where CalendarPipe is strong

Programmability nobody else offers
Sync rules as real TypeScript in an isolated sandbox: rewrite titles, filter by patterns, transform events – no other tool in this comparison lets you go this deep. For developers it's a dream.
Built for AI agents
A REST API, webhooks, an OpenAPI 3.1 spec and ready-made „agent skills" turn CalendarPipe into calendar infrastructure for agentic systems. If you want to give your AI agent a calendar, this is a well-thought-out foundation.
A data-minimal architecture
„We don't store your events" – events flow through the pipes instead of sitting on someone's servers, and the rule sandbox has no network access. That's a serious privacy approach, and we respect it.
A fair price with a free plan
A free entry with 2 connections and Pro at $4/month with everything included – on price, CalendarPipe is on par with us. A likeable, ambitious indie project.

Where Kalender Sync wins

Tap a point to see the reasoning.

  • Set up by click, not by code

    With Kalender Sync you pick accounts, direction and visibility in a few clicks – no rule editor, no sandbox, no TypeScript. The three visibility levels „busy only", „title + time" and „full details" are ready-made choices per sync, not rules you have to write yourself.

  • GMX & WEB.DE connected directly

    Alongside Google, Outlook/M365, Apple iCloud, Infomaniak kSuite, mailbox.org and iCal feeds, Kalender Sync also connects the German consumer providers GMX and WEB.DE – as the only tool in this comparison with dedicated one-click integrations, no manual CalDAV setup with server addresses and app passwords. If you need your private German mail calendar next to your work calendar, there's no way around this coverage.

  • A German company with a DPA

    Kalender Sync is run by PPJ Venture Labs UG (haftungsbeschränkt) in Munich and hosts at Hetzner in Nuremberg – GDPR- and BDSG-compliant, with a data processing agreement for business customers. CalendarPipe is a Czech indie project by two developers; we couldn't find a publicly available DPA there. For law firms, schools and companies, the contractual partner matters.

  • A synced calendar instead of single invitations

    CalendarPipe is primarily built to automate your own calendars with rules; on Pro it can additionally email events to other people as .ics invitations, which then update in their calendars. Kalender Sync takes a different route: the other person accepts an invitation once, and from then on your availability shows up as a continuously synced calendar inside their own calendar – with selectable visibility, in both directions.

  • Real time instead of intervals

    CalendarPipe syncs every 15 minutes on the free plan and every 5 minutes on Pro. On every plan, Kalender Sync synchronises Google and Outlook in real time via webhooks instead of on an interval. When only minutes lie between two meeting requests, exactly that decides over double bookings.

  • A permanently free plan plus a 7-day trial

    One sharing is permanently free with Kalender Sync, Basic costs €5/month, Professional €12/month – and you can test all Professional features for 7 days without a credit card. CalendarPipe Pro is nominally cheaper at $4/month. The difference lies in provider breadth, the DPA and live sharing.

When should you pick which?

CalendarPipe is the right choice if:

  • You're a developer and want to write your sync logic yourself in TypeScript.
  • You're looking for calendar infrastructure for AI agents (REST API, webhooks, OpenAPI, agent skills).
  • Filter and transformation rules matter more to you than provider breadth.
  • A young indie tool by two developers is no problem for you.

Kalender Sync is the right choice if:

  • You want your sync set up in minutes by clicking – no code, no rule editor.
  • You need a German contractual partner with a DPA and German-language support.
  • You want to share your availability live into other people's calendars – not just automate your own accounts.
  • You simply want to choose per sync between „busy only", „title + time" and full details.
  • You want the broadest provider coverage in this comparison: 10 provider types – Google, Microsoft Outlook/M365, Apple iCloud, GMX, WEB.DE, mailbox.org, Posteo, STRATO, Infomaniak kSuite and iCal feeds. Kalender Sync is the only tool in this comparison with dedicated one-click GMX & WEB.DE integrations – no manual CalDAV setup with server addresses and app passwords.
Try free for 7 days

Ready for calendar sync without a single line of code?

Connect your calendars in a few clicks – GDPR-compliant, hosted in Germany, with genuine live-sharing and three visibility levels per sync.

Try free for 7 days

Currently supported providers

GoogleMicrosoftApple iCloudKKSuiteGMXWEB.DEmailbox.orgiCal-Feeds