diff --git a/infra/terraform/modules/foundations/public_edge/main.tf b/infra/terraform/modules/foundations/public_edge/main.tf
index bc90ebd..25c7fea 100644
--- a/infra/terraform/modules/foundations/public_edge/main.tf
+++ b/infra/terraform/modules/foundations/public_edge/main.tf
@@ -42,7 +42,6 @@ resource "google_compute_backend_service" "api" {
   name                  = "${var.name_prefix}-api-backend"
   protocol              = "HTTP"
   load_balancing_scheme = "EXTERNAL_MANAGED"
-  timeout_sec           = 900
 
   backend { group = google_compute_region_network_endpoint_group.api.id }
 }
@@ -52,7 +51,6 @@ resource "google_compute_backend_service" "web" {
   name                  = "${var.name_prefix}-web-backend"
   protocol              = "HTTP"
   load_balancing_scheme = "EXTERNAL_MANAGED"
-  timeout_sec           = 300
 
   backend { group = google_compute_region_network_endpoint_group.web.id }
 }
diff --git a/infra/terraform/tools/config-validator/test/public-edge-assets.test.mjs b/infra/terraform/tools/config-validator/test/public-edge-assets.test.mjs
index da7c4b7..f3e399d 100644
--- a/infra/terraform/tools/config-validator/test/public-edge-assets.test.mjs
+++ b/infra/terraform/tools/config-validator/test/public-edge-assets.test.mjs
@@ -20,3 +20,8 @@ test("public-edge operations documentation covers rollout and rollback", () => {
     assert.match(operations, new RegExp(requiredText));
   }
 });
+
+test("serverless NEG backends do not set unsupported backend timeouts", () => {
+  const module = readFileSync(new URL("infra/terraform/modules/foundations/public_edge/main.tf", repositoryRoot), "utf8");
+  assert.doesNotMatch(module, /resource "google_compute_backend_service" "(?:api|web)" \{[\s\S]*?timeout_sec/);
+});