The light-4j framework is one of the fastest microservices/API frameworks on the market, and there is a lot of effort to make that happen. There are a lot of frameworks, languages to build microservices but most popular ones are Java, Go and Nodejs.
Nodejs used to be faster compared with Java EE platforms, but it has a lot of issues in the enterprise world.
Go has potentials but is still not mature in enterprise applications. We are starting with Java because it is highly optimized and there are so many existing investments in most organizations.
In Java, the most popular framework is Spring Boot, and a lot of users want to compare Light-4j with Spring Boot. We just started a new project light-spring-boot to allow Spring Boot applications to leverage the Light-4j middleware handlers to address cross-cutting concerns with better performance.
We have tested most of microservices frameworks and here is the benchmarks along with source code.
All the implementations for TechEmpower are following RESTful style although there are a lot of middleware handlers are removed. The source code can be used as an example of how to implement high-performance microservices.