diff --git a/src/app/api/circles/[id]/invite/route.ts b/src/app/api/circles/[id]/invite/route.ts
index c942c3d..27359a7 100644
--- a/src/app/api/circles/[id]/invite/route.ts
+++ b/src/app/api/circles/[id]/invite/route.ts
@@ -26,7 +26,7 @@ export async function POST(
 
     // Cryptographically random 32-byte token (64 hex chars) — unguessable
     const token     = randomBytes(32).toString("hex");
-    const expiresAt = new Date(Date.now() + 7 * 24 * 60 * 60 * 1000); // 7 days
+    const expiresAt = new Date(Date.now() + 7 * 24 * 60 * 60 * 1000).toISOString(); // 7 days
 
     const [invite] = await sql.unsafe(
       `INSERT INTO circle_invites (circle_id, token, created_by, expires_at)