diff --git a/packages/iios-service/src/main.ts b/packages/iios-service/src/main.ts
index 97ea751..62f0c32 100644
--- a/packages/iios-service/src/main.ts
+++ b/packages/iios-service/src/main.ts
@@ -9,6 +9,10 @@ import { PolicyDeniedFilter } from './platform/policy-denied.filter';
 
 async function bootstrap(): Promise<void> {
   const app = await NestFactory.create(AppModule, { rawBody: true });
+  // Express 5 defaults to the 'simple' query parser, which ignores nested params like
+  // ?metadata[key]=value — so generic metadata filters would be silently dropped. Use the
+  // qs-based 'extended' parser so those parse into a nested object.
+  app.getHttpAdapter().getInstance().set('query parser', 'extended');
   app.use(traceMiddleware); // request-scoped trace context + x-trace-id header (P9)
   app.useGlobalPipes(
     new ValidationPipe({ whitelist: true, forbidNonWhitelisted: true, transform: true }),