diff --git a/backend/package.json b/backend/package.json
index 096d748d..2b04044f 100644
--- a/backend/package.json
+++ b/backend/package.json
@@ -21,7 +21,6 @@
         "dotenv": "^16.4.7",
         "express": "^5.0.1",
         "uuid": "^11.1.0",
-        "express": "^5.0.1",
         "js-yaml": "^4.1.0",
         "@types/js-yaml": "^4.0.9"
     },
diff --git a/backend/src/app.ts b/backend/src/app.ts
index b0f7afa2..7a25fa2b 100644
--- a/backend/src/app.ts
+++ b/backend/src/app.ts
@@ -4,13 +4,13 @@ import { EnvVars, getNumericEnvVar } from './util/envvars.js';
 
 import themeRoutes from './routes/themes.js';
 
-import studentRouter from './routes/student';
-import groupRouter from './routes/group';
-import assignmentRouter from './routes/assignment';
-import submissionRouter from './routes/submission';
-import classRouter from './routes/class';
-import questionRouter from './routes/question';
-import loginRouter from './routes/login';
+import studentRouter from './routes/student.js';
+import groupRouter from './routes/group.js';
+import assignmentRouter from './routes/assignment.js';
+import submissionRouter from './routes/submission.js';
+import classRouter from './routes/class.js';
+import questionRouter from './routes/question.js';
+import loginRouter from './routes/login.js';
 
 const app: Express = express();
 const port: string | number = getNumericEnvVar(EnvVars.Port);