diff --git a/nixos/modules/services/networking/firefox-syncserver.nix b/nixos/modules/services/networking/firefox-syncserver.nix
index 56f204c50c7c..6a50e49fc096 100644
--- a/nixos/modules/services/networking/firefox-syncserver.nix
+++ b/nixos/modules/services/networking/firefox-syncserver.nix
@@ -13,7 +13,7 @@ let
   defaultUser = "firefox-syncserver";
 
   dbIsLocal = cfg.database.host == "localhost";
-  dbURL = "mysql://${cfg.database.user}@${cfg.database.host}/${cfg.database.name}";
+  dbURL = "mysql://${cfg.database.user}@${cfg.database.host}/${cfg.database.name}${lib.optionalString dbIsLocal "?socket=/run/mysqld/mysqld.sock"}";
 
   format = pkgs.formats.toml { };
   settings = {
diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix
index fcdb5d23b124..2dbe012709bf 100644
--- a/nixos/tests/all-tests.nix
+++ b/nixos/tests/all-tests.nix
@@ -569,6 +569,7 @@ in
     imports = [ ./firefox.nix ];
     _module.args.firefoxPackage = pkgs.firefox-esr-140;
   };
+  firefox-syncserver = runTest ./firefox-syncserver.nix;
   firefoxpwa = runTest ./firefoxpwa.nix;
   firejail = runTest ./firejail.nix;
   firewall = runTest {
diff --git a/nixos/tests/firefox-syncserver.nix b/nixos/tests/firefox-syncserver.nix
new file mode 100644
index 000000000000..04b6fdc88711
--- /dev/null
+++ b/nixos/tests/firefox-syncserver.nix
@@ -0,0 +1,32 @@
+{
+  pkgs,
+  ...
+}:
+
+{
+  name = "firefox-syncserver";
+  nodes.machine = {
+    services.mysql = {
+      enable = true;
+      package = pkgs.mariadb;
+    };
+
+    services.firefox-syncserver = {
+      enable = true;
+      secrets = pkgs.writeText "secret" "this-is-a-test";
+      singleNode = {
+        enable = true;
+        hostname = "firefox-syncserver.local";
+        capacity = 1;
+      };
+    };
+  };
+
+  testScript = ''
+    machine.wait_for_unit("firefox-syncserver.service")
+    machine.wait_for_open_port(5000)
+
+    machine.wait_until_succeeds("curl --fail http://127.0.0.1:5000")
+
+  '';
+}
diff --git a/pkgs/by-name/sy/syncstorage-rs/package.nix b/pkgs/by-name/sy/syncstorage-rs/package.nix
index 8d91b26ae515..43e6eaa62bf2 100644
--- a/pkgs/by-name/sy/syncstorage-rs/package.nix
+++ b/pkgs/by-name/sy/syncstorage-rs/package.nix
@@ -8,6 +8,7 @@
   makeBinaryWrapper,
   lib,
   nix-update-script,
+  nixosTests,
 }:
 
 let
@@ -54,6 +55,8 @@ rustPlatform.buildRustPackage rec {
 
   passthru.updateScript = nix-update-script { };
 
+  passthru.tests = { inherit (nixosTests) firefox-syncserver; };
+
   meta = {
     description = "Mozilla Sync Storage built with Rust";
     homepage = "https://github.com/mozilla-services/syncstorage-rs";