diff --git a/common/ApiError.ts b/common/ApiError.ts
index 972ee11..ff48b6d 100644
--- a/common/ApiError.ts
+++ b/common/ApiError.ts
@@ -22,11 +22,11 @@ export default class ApiError extends Error {
     }
   }
 
-  toJSON() {
+  toJSON(development: boolean = false) {
     return {
       message: this.message,
       code: this.code,
-      data: this.data
+      data: development ? this.data : undefined
     };
   }
 }
diff --git a/server/express/errorHandler.ts b/server/express/errorHandler.ts
index e161a0f..6f183ea 100644
--- a/server/express/errorHandler.ts
+++ b/server/express/errorHandler.ts
@@ -1,6 +1,9 @@
 import * as express from "express";
 
 import ApiError from "@common/ApiError";
+import { ErrorCode } from "@common/ErrorCode";
+
+const isDev = process.env.NODE_ENV === "development";
 
 const errorHandler: express.ErrorRequestHandler = (
   err: any,
@@ -9,9 +12,11 @@ const errorHandler: express.ErrorRequestHandler = (
   next: express.NextFunction
 ) => {
   if (err instanceof ApiError) {
-    res.status(err.statusCode).json(err.toJSON());
+    // TODO: different content-type?
+    res.status(err.statusCode).json(err.toJSON(isDev));
   } else {
-    next(err);
+    const internalError = new ApiError("An internal server error has occurred", ErrorCode.Internal);
+    errorHandler(internalError, req, res, next);
   }
 };