Netty-rest is a high performance HTTP and WebSocket server implementation based on Netty. It uses javax.ws.rs annotations and generates Java bytecode at runtime in order to provide best performance. It basically maps the java methods to endpoints and takes care of validation, serialization / deserialization, authentication and designed for minimum overhead and maximum performance. It can generate Swagger specification automatically so that you can generate client libraries, API documentation easily. If you don't pass one of the parameters, the server will return 400 response, you can also use complex java beans in parameters and method return signature. The library uses Jackson for serialization of the object that you passed and deserialization of the JSON attributes. It will be mapped to the parameters and the method will be invoked for the API calls.