Valheim is an incredibly popular survival game that has taken the gaming world by storm. With its unique Nordic setting, engaging combat, and captivating exploration, it’s no surprise that so many players have been drawn to it.

In order to host a Valheim server you can use a third party hosting provider (like ServerFlex).  Alternatively you can download the Steam CLI and install and run the server manually. Crossplay is supported for both methods. For more details on hosting a Valheim server on Linux, see here.

How do I enable crossplay between Steam and Microsoft Store?

The -crossplay argument when running the server from the CLI will determine if crossplay is supported. To start a Valheim server from the CLI, allowing crossplay, use the following command:

./valheim_server.x86_64 -world world -name My Server -crossplay

To enable crossplay on your Valheim server on ServerFlex, go to the control panel settings in ServerFlex and look for the "Allow Crossplay" button.

The ServerFlex Control Panel Valheim Settings.

For more details on how to enable crossplay on your Valheim server on ServerFlex, read here:

How to enable crossplay on a Valheim server | Valheim | ServerFlex
In the recent update (Patch 0.211.7) for Valheim’s server, a new command line parameter was added to enable crossplay. It is not enabled by default.
ServerFlexServerFlex