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Kalender Sync
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Tool comparison

Kalender Sync vs. OneCal – which sync fits you?

OneCal is a mature sync tool with booking links and mobile apps – but runs on AWS. Kalender Sync focuses on pure sync, hosting in Germany and a selectable detail level per sync – Free/Busy by default. Here's the honest comparison.

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Background

What is OneCal?

OneCal is an international sync tool that connects Google Calendar, Microsoft Outlook and Apple iCloud in real time. Multi-way sync, booking links, a unified calendar view and native iOS/Android apps are part of the feature set. Privacy is controlled via configurable visibility rules – e.g. transferring only "busy" instead of event content. The platform runs on AWS, with security features like private VPC, encryption in transit and at rest, and regular vulnerability scans.

Strengths

Where OneCal is strong

Polished UX and mobile apps

OneCal has a polished interface, integrated unified calendar view and native iOS/Android apps. If you want sync, booking links and calendar management in one app, this is it.

Granular visibility control

Per sync, you can decide whether title, description, location and attendees are transferred – or only "busy". Very fine-grained tuning is possible.

Booking links included

Customisable scheduling links with branding, buffers and reminders – usable as a Calendly replacement.

Where Kalender Sync wins

Where Kalender Sync wins

Hosting in Germany, not AWS

OneCal runs on AWS – even with EU-region servers, the US Cloud Act applies to the parent company. Kalender Sync hosts at Hetzner in Nuremberg, German company, German servers, no US cloud dependency.

Real calendar sharing – not just booking links

OneCal has scheduling links so others can book with you. What OneCal can't do: embed your calendar as a live feed inside someone else's calendar, kept automatically in sync there. That's a core feature of Kalender Sync.

One sharing always free – no trial expiry

OneCal has a 14-day trial, then every plan costs money. At Kalender Sync, one sharing is permanently included in the Free plan – if all you want is to show your availability, you never pay. Syncing your own calendars starts on Basic.

Three visibility levels – Free/Busy by default

With OneCal you configure visibility per sync yourself. At Kalender Sync, "busy only" is the default – event details only leave your calendar if you explicitly allow it. That matters for audits and works councils.

Provider breadth beyond the big three

OneCal supports Google, Outlook and iCloud. Kalender Sync additionally connects the German providers GMX and WEB.DE, KSuite (Infomaniak, Swiss provider) and any iCal feeds – important for mixed EU setups.

Better price-to-value at entry

OneCal's Starter plan is $5 per user per month. Kalender Sync Basic is €5/month – and includes three calendar accounts and five syncs. Annual billing saves two months, effective rate ~€4.17/month.

A DPA with a German contractual partner

A data processing agreement (DPA) with a German contractual partner is included in Kalender Sync's Professional plan and available on request for Free and Basic. For businesses with works councils, a clear advantage.

Decision guide

When to pick which

OneCal is the right choice when:

  • You need a polished mobile app and unified view.
  • US cloud hosting isn't critical for you.
  • You want booking links out of the same tool.

Kalender Sync is the right choice when:

  • You're in the EU/DACH and take privacy seriously.
  • You serve regulated industries (tax, medical, education, legal).
  • You want the broadest provider coverage in this comparison: 8 provider types – Google, Microsoft Outlook/M365, Apple iCloud, GMX, WEB.DE, mailbox.org, Infomaniak kSuite and iCal feeds. Kalender Sync is the only tool in this comparison that connects the German providers GMX & WEB.DE.
  • You want Free/Busy as the data-minimal default – with three visibility levels per sync.

Ready for calendar sync that passes the DACH compliance test?

Connect your calendars in a few clicks – GDPR-compliant and hosted in Germany.

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Currently supported providers

GoogleMicrosoftApple iCloudKKSuiteGMXWEB.DEmailbox.orgiCal-Feeds