diff --git a/app.js b/app.js
index 1b4ababa6..bc8e702c4 100644
--- a/app.js
+++ b/app.js
@@ -11,6 +11,14 @@ import cookieSession from 'cookie-session';
 import express from 'express';
 import morgan from 'morgan';
 
+if (process.env.NODE_ENV === 'production') {
+  for (const key of ['SECRET', 'SALT', 'SECRET_KEY_1', 'SECRET_KEY_2']) {
+    if (!process.env[key]) {
+      throw new Error(`Missing required environment variable in production: ${key}`);
+    }
+  }
+}
+
 const app = express();
 if (process.env.NODE_ENV !== 'production') {
   app.use(morgan('dev'));