diff --git a/aws/rust-runtime/aws-endpoint/external-types.toml b/aws/rust-runtime/aws-endpoint/external-types.toml
new file mode 100644
index 0000000000000000000000000000000000000000..a121d9e1236e24f32d33bd5bc0605dee1356c6ef
--- /dev/null
+++ b/aws/rust-runtime/aws-endpoint/external-types.toml
@@ -0,0 +1,5 @@
+allowed_external_types = [
+    "aws_types::*",
+    "aws_smithy_http::property_bag::PropertyBag",
+    "aws_smithy_http::middleware::MapRequest",
+]