Contribute or troubleshoot

To report an issue, please go to

You can also chat with us on the Libera IRC channel #nixos-mailserver.

Run NixOS tests

To run the test suite, you need to enable Nix Flakes <>.

You can then run the testsuite via

$ nix flake check -L

Since Nix doesn’t garantee your machine have enough resources to run all test VMs in parallel, some tests can fail. You would then haev to run tests manually. For instance:

$ nix build .#hydraJobs.x86_64-linux.external-unstable -L

Contributing to the documentation

The documentation is written in RST, build with Sphinx and published by Read the Docs.

For the syntax, see RST/Sphinx Cheatsheet.

The shell.nix provides all the tooling required to build the documentation:

$ nix-shell
$ cd docs
$ make html
$ firefox ./_build/html/index.html

Note if you modify some NixOS mailserver options, you would also need to regenerate the options.rst file:

$ nix-shell --run generate-rst-options


You can test the setup via nixops. After installation, do

$ nixops create nixops/single-server.nix nixops/vbox.nix -d mail
$ nixops deploy -d mail
$ nixops info -d mail

You can then test the server via e.g. telnet. To log into it, use

$ nixops ssh -d mail mailserver


To test imap manually use

$ openssl s_client -host -port 143 -starttls imap