diff --git a/nix/module.nix b/nix/module.nix
index 75adc4f..742f739 100644
--- a/nix/module.nix
+++ b/nix/module.nix
@@ -8,7 +8,7 @@ self: {
   inherit (builtins) toJSON toString;
   inherit (lib.modules) mkIf;
   inherit (lib.options) mkOption mkEnableOption literalExpression;
-  inherit (lib.types) package str port int listOf enum bool attrsOf path;
+  inherit (lib.types) package str int listOf enum bool attrsOf path;
   inherit (lib.lists) optionals;
 
   cfg = config.services.eris;
@@ -30,6 +30,7 @@ self: {
     config_dir = "${cfg.stateDir}/conf";
     cache_dir = cfg.cacheDir;
     disable_metrics = cfg.disableMetrics;
+    log_format = cfg.logFormat;
   });
 in {
   ###### interface
@@ -134,6 +135,12 @@ in {
         description = "Logging level for the Eris service.";
       };
 
+      logFormat = mkOption {
+        type = enum ["Plain" "Pretty" "Json" "PrettyJson"];
+        default = "Pretty";
+        description = "Logging format for Eris.";
+      };
+
       user = mkOption {
         type = str;
         default = "eris";