Tool comparison

Kalender Sync vs. MergeCal – feed merger or real sync?

MergeCal and Kalender Sync often get mentioned in the same breath – yet they solve different problems. MergeCal is a feed merger: it bundles many iCal calendars into a single subscription link. Kalender Sync is a sync service: it writes real events into your calendars, in both directions. Both have their place – here's an honest look at when each tool is the right one.

Try free for 7 days See the MergeCal view

Background

What can MergeCal do?

MergeCal is an open-source project (AGPL-3.0, Django/Python) by the US company MergeCal, Inc. that combines any number of iCal/ICS feeds into a single merged feed. Sources can be Google, Apple, Outlook, but also Meetup, Discord, Twitch or booking platforms like Viator and GetYourGuide. You then subscribe to the combined feed in your calendar app or drop it into listing sites – a popular use case is showing vacation-rental availability across multiple portals. Pricing: Personal at $2/month (2 combined calendars with up to 3 feeds each, updates every 12 hours), Business at $10/month (5 calendars with 5 feeds each, real-time updates), Supporter at $20/month (unlimited), each with a 14-day trial without a credit card. The project is actively maintained and has its own community.

Where MergeCal is strong

One subscription link instead of ten: If you just want to view many calendars – club dates, community events, occupancy schedules – a single combined feed is exactly the right abstraction. Subscribe once, and every source shows up in one view. For that job, MergeCal is a clean tool.
Exotic feed sources: Meetup, Discord events, Twitch stream schedules, Viator and GetYourGuide bookings: MergeCal accepts any iCal feed, which makes it especially attractive for vacation-rental hosts and community organisers – a niche classic sync tools don't serve at all.
Open source with an affordable entry: The code is open on GitHub under AGPL-3.0, the project is actively developed, and at $2/month the Personal plan is a very affordable entry point. A likeable, transparently built product.

Where Kalender Sync wins

Tap a point to see the reasoning.

Real events instead of a read-only feed

The fundamental difference: MergeCal delivers an ICS subscription – your calendar merely displays the events. Kalender Sync writes real events into the target calendar via API. That difference becomes practical the moment availability matters: subscribed feeds are often ignored by booking tools and colleagues doing free/busy lookups – real events block reliably.
Freshness that doesn't depend on your calendar app

How often an ICS subscription refreshes is up to the calendar app – Google Calendar, for instance, refreshes external feeds on its own schedule, sometimes only after hours. Kalender Sync actively writes changes into the target calendar via API – for Google and Outlook in real time via webhook on every plan – regardless of when the app would next poll a feed.
Two-way sync instead of a one-way street

A merged feed is by definition a one-way street: you can't edit the events at the destination, and nothing flows back. Kalender Sync synchronises bidirectionally – changes in any connected calendar land everywhere.
Three visibility levels per sync

With Kalender Sync you decide per synchronisation what arrives: "busy only", "title + time" or "full details" – with custom display names for blocked slots. A feed merger passes events through; fine-grained data minimisation per recipient is a sync feature.
Live-sharing into other calendars

Kalender Sync embeds your availability directly into another person's calendar by invitation – as real events, without them having to subscribe to or maintain a feed. They accept once, and from then on everything stays in sync automatically.
A German privacy stack with a DPA

Kalender Sync is run by PPJ Venture Labs UG in Munich, GDPR- and BDSG-compliant, hosted at Hetzner in Nuremberg, with a DPA on every plan for business use. MergeCal is a US Inc.; its privacy policy contains no statements on GDPR, EU hosting or a DPA that we could find. For law firms, schools and companies, that's a deal-breaker.
10 provider types and a permanently free plan

Kalender Sync connects 10 provider types – Google, Microsoft Outlook/M365, Apple iCloud, GMX, WEB.DE, mailbox.org, Posteo, STRATO, Infomaniak kSuite and iCal feeds. As the only tool in this comparison, it offers a ready-made integration for the German providers GMX and WEB.DE – real events instead of a read-only feed. One sharing is permanently free, then Basic from €5/month and Professional at €12/month – whereas MergeCal's trial ends after 14 days.

When should you pick which?

MergeCal is the right choice if:

You just want to view many calendars in one place – with no channel back.
You want to bundle feeds from Meetup, Discord, Twitch or booking platforms.
You're a rental host and need occupancy from several portals in one feed.
A read-only ICS subscription is enough for you – updated every 12 hours on Personal, in real time on the higher plans.

Kalender Sync is the right choice if:

Your events should block as real entries – not just show up as a subscribed overlay.
You need two-way sync: changes flow in both directions.
You want to share your availability live into other people's calendars – with selectable visibility per sync.
You need a German contractual partner with a DPA, GDPR/BDSG compliance and Hetzner hosting.
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 a ready-made integration for the German providers GMX & WEB.DE – real events instead of a read-only feed.

Try free for 7 days

Ready for real events instead of read-only feeds?

Connect your calendars in a few clicks – GDPR-compliant, hosted in Germany, with two-way sync and genuine live-sharing.

Try free for 7 days

Currently supported providers

GoogleMicrosoftApple iCloudKSuiteGMXWEB.DEmailbox.orgiCal-Feeds