diff --git a/server/src/app.ts b/server/src/app.ts
index 1faab285..5ce4e292 100644
--- a/server/src/app.ts
+++ b/server/src/app.ts
@@ -121,6 +121,9 @@ export async function createApp(
     }),
   );
   app.use("/api", api);
+  app.use("/api", (_req, res) => {
+    res.status(404).json({ error: "API route not found" });
+  });
 
   const __dirname = path.dirname(fileURLToPath(import.meta.url));
   if (opts.uiMode === "static") {