diff --git a/server.js b/server.js
index 397c3c7..e5da678 100644
--- a/server.js
+++ b/server.js
@@ -753,7 +753,7 @@ app.post('/api/chat', requireAuth, async (req, res) => {
           'Content-Type': 'application/json'
         },
         body: JSON.stringify({
-          model: process.env.OPENROUTER_MODEL,
+          model: process.env.OPENROUTER_MODEL || 'openai/gpt-4.1-nano',
           messages: enrichedMessages,
           stream: true
         })