diff --git a/backend/src/controllers/learningObjects.ts b/backend/src/controllers/learningObjects.ts
index 2d733d97..d0df24fd 100644
--- a/backend/src/controllers/learningObjects.ts
+++ b/backend/src/controllers/learningObjects.ts
@@ -1,6 +1,6 @@
 import { Request, Response } from 'express';
 import { getLearningObjectsFromPath } from '../services/learningObjects.js';
-import { FALLBACK_LANG } from '../config';
+import { FALLBACK_LANG } from '../config.js';
 
 export async function getAllLearningObjects(
     req: Request,
diff --git a/backend/src/controllers/themes.ts b/backend/src/controllers/themes.ts
index 62564485..817464ab 100644
--- a/backend/src/controllers/themes.ts
+++ b/backend/src/controllers/themes.ts
@@ -3,7 +3,7 @@ import path from 'path';
 import yaml from 'js-yaml';
 import { Request, Response } from 'express';
 import { themes } from '../data/themes.js';
-import { FALLBACK_LANG } from '../config';
+import { FALLBACK_LANG } from '../config.js';
 
 interface Translations {
     curricula_page: {