diff --git a/frontend/src/services/api.ts b/frontend/src/services/api.ts
index b2f7a16..eb6f825 100644
--- a/frontend/src/services/api.ts
+++ b/frontend/src/services/api.ts
@@ -450,7 +450,7 @@ export async function getProjectShares(token: string, projectId: string): Promis
 export async function createProjectShare(token: string, projectId: string, data: { shared_with_email: string; permission?: string }): Promise<ProjectShare> {
   const res = await fetch(`${API_BASE}/api/projects/${projectId}/shares`, {
     method: 'POST',
-    headers: authHeaders(token),
+    headers: { ...authHeaders(token), 'Content-Type': 'application/json' },
     body: JSON.stringify(data),
   });
   if (!res.ok) throw new Error('Failed to create share');