How to Sync Mailcow Calendar with Nextcloud Calendar

How to Sync Mailcow Calendar with Nextcloud Calendar.

Do they support caldav? Then you could just access remotely to the Nextcloud calendar.

If not you can export and import calendars:

Or you would need something like this:

but for mailcow.

Sorry to not know mailcow, perhaps someone is using it here and give a better response.

I do not use Mailcow, so I am not an expert. I don’t know if a read/write synchronization is possible. Did you already try to do it the other way around, to synch your nextcloud calendar with Mailcow?

But you can subscribe to your Mailcow calendar like you can subscribe to your personal Google Calendar. How the link has to look like is described/discussed here: Direct link to calendar - mailcow community.

A subscription gives you a read-only access to that calendar.

Then you only have to set a reasonable refreshrate. The default refreshrate for subscribed calendars is about one week, so once in a week it get refreshed.

If you want to shorten that refreshrate, you have two options:

  1. Shorten refreshrate for all subscribed calendars like described in the manual: Calendar / CalDAV β€” Nextcloud latest Administration Manual latest documentation
    That wil change the refreshrate for all subscribed calendars for all users on your instance.

But subscribed calendars with religious or legal holidays or moon phases can be upated once a month or even once a year while subscribed personal callendars like from google or Mailcow would have to be synchronized up to every 15 minutes or sometimes even more often depending on the individual case.
There is a hidden posibility to set the refreshrate for each single subscribed calendar apart. Unfortunately it hasn’t made it into the user interface. There is a column for it in the database, but you have to set it manually in the SQL console. But to make things easy, I wrote a script, that gives you the means to set the refreshrate of your subscribed calendars to your choice. Every single calendar to its own refreshrate:

  1. Shorten refreshrate on a per calender basis with the script nc-subscribed-calendar
    This is how to install the script:
sudo wget -qO /usr/local/bin/nc-subscribed-calendar
sudo chmod +x /usr/local/bin/nc-subscribed-calendar

Now simply run it:


The script will guide you through the steps.

Restriction: Only for MySQL/MariaDB
[Edit]: For MySQL/MariaDB and PostgreSQL

I hope you find your ideal solution with this information


Mailcow use Sogo and so has Caldav and Cardav support: Manual configuration - mailcow: dockerized documentation. Assuming you want to truly sync calendars instead of integrating via a subscribing feature the tool you want to use is vdirsyncer, thankfully there is a Nextcloud app for configuring it: vdirsyncer UI - Apps - App Store - Nextcloud Not sure how good that app is but vdirsyncer itself is quite solid and been around for a while now.

Or you could keep things simple, and only use one of the two groupware solutions. (Nextcloud or Sogo) :wink:

I’m also running a Mailcow server, but only as an email server, without Sogo. I have installed Roundcube on in, in which I have integrated the Nextcloud contacts, but I rarely ever use it

Yeah I use the docker-mailserver container with Nextcloud mail as the web interface for the same reason. But more options are more good.