diff --git a/configuration.nix b/configuration.nix
index 7b25d56..dd96bb6 100644
--- a/configuration.nix
+++ b/configuration.nix
@@ -83,6 +83,10 @@
   ];
   environment.pathsToLink = [ "/share/fish" ];
 
+  # Needed for Slack but probably helps other stuff too.
+  # See https://wiki.nixos.org/wiki/Slack
+  environment.sessionVariables.NIXOS_OZONE_WL = "1";
+
   # Make it possible for ddev to modify the /etc/hosts file.
   # Otherwise you'll have to manually change the
   # hosts configuration after creating a new ddev project.