Kalender Sync

Keeps Google, Outlook, iCloud and CalDAV calendars in sync one- or two-way and connects them to ChatGPT and Claude, so agents can check availability, find events and create bookings across all calendars

Freemium Productivity
Visit Website ↗ by Kalender Sync

What is Kalender Sync?

Kalender Sync connects Outlook, iCloud, Google, GMX, WEB.DE, mailbox.org, Posteo, STRATO and kSuite in real time — one-way or two-way — so blocked slots appear on their own and double bookings stop happening. Per sync you decide what is visible: only busy, title plus time, or full details, even with a custom label for a blocked slot.

You can also connect your AI agent — Claude, ChatGPT, Codex and others — to your calendars in about two minutes with no keys: the agent finds free time across all your calendars, suggests times that are actually free, drafts the mail with the suggestions and enters the booking on request. Per-calendar permissions, a timestamped access log and one-click revocation keep agent access auditable, and the service is GDPR-compliant and hosted in Germany, from €5 per month.

Key features

  • One- or two-way sync across Outlook, Google, iCloud and more
  • Three visibility levels per sync, including custom labels for busy slots
  • AI-agent connections for ChatGPT, Claude and Codex with no keys to manage
  • Per-calendar permissions with a timestamped access log
  • Calendar sharing with others via invite
  • GDPR-compliant hosting in Germany

Pros

  • One connection covers your whole calendar life, not a single account
  • Access log and one-click revoke keep agent access auditable

Cons

  • The homepage is in German, which may slow non-German speakers

Kalender Sync at a glance

PricingFreemium
CategoryProductivity
Platformsweb
CompanyKalender Sync
Best forPeople juggling several calendars across providers who also want AI assistants to book for them
Official websitekalender-sync.de
calendar syncoutlookgoogle calendaricloudai agents

How to choose the right Productivity tool

When choosing a productivity tool, look first at how it fits the way you already work. The best tools connect with the apps you use every day — email, calendar, documents and chat — instead of becoming one more place to check. Automation matters most where work repeats: summaries, reminders, scheduling and turning notes into tasks are where AI genuinely saves time. Check whether the free tier covers your real usage, how the tool handles your data and privacy, and whether it works on the platforms you live on — web, desktop and mobile. A slightly less powerful tool that your whole team actually adopts beats a feature-rich one nobody opens.

Compare all Productivity tools →

Kalender Sync FAQs

What is Kalender Sync?

Kalender Sync connects Outlook, iCloud, Google, GMX, WEB.DE, mailbox.org, Posteo, STRATO and kSuite in real time — one-way or two-way — so blocked slots appear on their own and double bookings stop happening. Per sync you decide what is visible: only busy, title plus time, or full details, even with a custom label for a blocked slot.

What are the main features of Kalender Sync?

Kalender Sync offers One- or two-way sync across Outlook, Google, iCloud and more, Three visibility levels per sync, including custom labels for busy slots, AI-agent connections for ChatGPT, Claude and Codex with no keys to manage, Per-calendar permissions with a timestamped access log, Calendar sharing with others via invite and GDPR-compliant hosting in Germany.

How much does Kalender Sync cost?

Kalender Sync follows a freemium model: a free tier is available, and paid plans unlock higher limits and advanced features. Check its official website for current plan prices.

What are the pros and cons of Kalender Sync?

Strengths of Kalender Sync include One connection covers your whole calendar life, not a single account; Access log and one-click revoke keep agent access auditable. On the downside, The homepage is in German, which may slow non-German speakers.