diff --git a/nixbld-etc-nixos/configuration.nix b/nixbld-etc-nixos/configuration.nix
index e519626..2e19108 100644
--- a/nixbld-etc-nixos/configuration.nix
+++ b/nixbld-etc-nixos/configuration.nix
@@ -119,6 +119,11 @@ ACTION=="add", SUBSYSTEM=="tty", \
     rootUrl = "https://git.m-labs.hk/";
   };
 
+  services.mattermost = {
+    enable = true;
+    siteUrl = "https://chat.m-labs.hk/";
+  };
+
   services.nginx = {
     enable = true;
     recommendedProxySettings = true;
@@ -143,6 +148,11 @@ ACTION=="add", SUBSYSTEM=="tty", \
         enableACME = true;
         locations."/".proxyPass = "http://127.0.0.1:3001";
       };
+      "chat.m-labs.hk" = {
+        forceSSL = true;
+        enableACME = true;
+        locations."/".proxyPass = "http://127.0.0.1:8065";
+      };
     };
   };