diff --git a/nix/nixos-module.nix b/nix/nixos-module.nix
index 00b01bb..3fa4f64 100644
--- a/nix/nixos-module.nix
+++ b/nix/nixos-module.nix
@@ -39,6 +39,16 @@ let
       description = "Environment variables passed to the service.";
     };
 
+    logLevel = mkOption {
+      type = types.nullOr (types.enum (builtins.attrValues logLevels));
+      default = null;
+      example = logLevels.info;
+      description = ''
+        Log level to pass as RUST_LOG. Leave unset to use the service default or
+        set a custom RUST_LOG value through environment.
+      '';
+    };
+
     extraArgs = mkOption {
       type = types.listOf types.str;
       default = [ ];
@@ -106,6 +116,19 @@ let
 
   cfg = config.services.microcosm;
 
+  constellationBackends = {
+    memory = "memory";
+    rocks = "rocks";
+  };
+
+  logLevels = {
+    error = "error";
+    warn = "warn";
+    info = "info";
+    debug = "debug";
+    trace = "trace";
+  };
+
   optionalArg =
     flag: value:
     optionals (value != null) [
@@ -117,6 +140,11 @@ let
     name: args:
     let
       service = cfg.${name};
+      environment =
+        service.environment
+        // lib.optionalAttrs (service.logLevel != null) {
+          RUST_LOG = service.logLevel;
+        };
     in
     mkIf service.enable {
       systemd.services."microcosm-${name}" = {
@@ -124,7 +152,7 @@ let
         wantedBy = [ "multi-user.target" ];
         wants = [ "network-online.target" ];
         after = [ "network-online.target" ];
-        environment = service.environment;
+        inherit environment;
 
         serviceConfig = {
           DynamicUser = true;
@@ -149,11 +177,8 @@ in
       jetstream = jetstreamOption;
       dataDir = statePathOption "/var/lib/microcosm/constellation" "Directory for RocksDB data.";
       backend = mkOption {
-        type = types.enum [
-          "memory"
-          "rocks"
-        ];
-        default = "rocks";
+        type = types.enum (builtins.attrValues constellationBackends);
+        default = constellationBackends.rocks;
         description = "Storage backend to use.";
       };
       didWebDomain = mkOption {
@@ -250,7 +275,7 @@ in
         cfg.constellation.backend
       ]
       ++ optionalArg "--jetstream" cfg.constellation.jetstream
-      ++ optionals (cfg.constellation.backend == "rocks") [
+      ++ optionals (cfg.constellation.backend == constellationBackends.rocks) [
         "--data"
         cfg.constellation.dataDir
       ]