diff --git a/substrate/core/rpc-servers/src/lib.rs b/substrate/core/rpc-servers/src/lib.rs
index 3f408f6684a0395ae940d14aa841afd3623175fe..8d39386f93c4ae9c79c0504beb7397914a3477c8 100644
--- a/substrate/core/rpc-servers/src/lib.rs
+++ b/substrate/core/rpc-servers/src/lib.rs
@@ -60,7 +60,9 @@ pub fn rpc_handler<M: PubSubMetadata>(
 mod inner {
 	use super::*;
 
+	/// Type alias for http server
 	pub type HttpServer = http::Server;
+	/// Type alias for ws server
 	pub type WsServer = ws::Server;
 
 	/// Start HTTP server listening on given address.