How can I set a custom map server for downloads?
As of December 2025 there is a new feature for Android, Custom Map Server.
You can set a custom map server from the world overview map download screen which you will see after installing CoMaps (this one is not present in the Google Play version as the world map is bundled there) or from the bottom of the Settings menu, which allows you to specify a Custom Map Server URL.
This option can be useful for different use cases. For example, it allows you avoid connecting to servers in regions you would prefer to avoid. Or if you are having a fleet of devices that run CoMaps but don't want to or cannot download the new maps over and over again from the internet as you are on a bandwidth-restricted or slow connection. E.g. if you are a humanitarian organisation deploying a team to a remote area, can now set up a local map server and distribute it locally via Wifi, no further connection needed.
The Custom Server URL should be an HTTP or HTTPS server that hosts files in the same structure as on our official CDNs. Currently, the custom server needs to host still needs to serve the officially generated by CoMaps. For now, CoMaps will still reject map file downloads that do not match the checksum from the countries.txt file bundled inside the app.
This strict bundling will likely change in the future, but is currently in place to ensure that the map and app version are compatible and to prevent malicious maps from making it into the app and causing undesirable behavior.
You can find a list of valid URLs hosted by CoMaps here, under the $servers variable in our meta-php repository: https://codeberg.org/comaps/meta-php/src/branch/main/index.php#L19
For help on how to setup your own map server, read this FAQ entry.