diff --git a/src/schemas/api.ts b/src/schemas/api.ts
index 601fa00..d3f2e2a 100644
--- a/src/schemas/api.ts
+++ b/src/schemas/api.ts
@@ -44,7 +44,7 @@ export const ExerciseTranslationSchema = z.object({
   license: z.number().int().positive(),
   license_title: z.string(),
   license_object_url: z.string(),
-  license_author: z.string(),
+  license_author: z.string().nullable(),
   license_author_url: z.string(),
   license_derivative_source_url: z.string(),
   author_history: z.array(z.string()),
diff --git a/src/types/wger.ts b/src/types/wger.ts
index f2a93f5..d4bf684 100644
--- a/src/types/wger.ts
+++ b/src/types/wger.ts
@@ -56,7 +56,7 @@ export interface ExerciseTranslation {
   /** License object URL */
   license_object_url: string;
   /** Author of the license */
-  license_author: string;
+  license_author: string | null;
   /** Author URL */
   license_author_url: string;
   /** Derivative source URL */
@@ -111,7 +111,7 @@ export interface Exercise {
   /** License object */
   license: License;
   /** Author of the exercise content */
-  license_author: string;
+  license_author: string | null;
   /** Array of image objects */
   images: unknown[];
   /** Array of translation objects with name and description in multiple languages */