diff --git a/services/mam-api/src/middleware/auth.js b/services/mam-api/src/middleware/auth.js
index 2e5707a..374aacf 100644
--- a/services/mam-api/src/middleware/auth.js
+++ b/services/mam-api/src/middleware/auth.js
@@ -3,7 +3,7 @@ import { parseBearer, hashToken } from '../auth/tokens.js';
 
 // Stable UUID matching migration 023's seeded dev user.
 /** UUID of the seeded dev-mode placeholder. NOT a sentinel for "any unauthenticated user". */
-export const DEV_USER_ID = '00000000-0000-4000-8000-000000000dev';
+export const DEV_USER_ID = '00000000-0000-4000-8000-000000000000';
 export const DEV_USER    = { id: DEV_USER_ID, username: 'dev', display_name: 'Dev (AUTH_ENABLED=false)' };
 
 const ABSOLUTE_MS = 8 * 3600 * 1000;