I write web services in enterprise Java using JAXRS annotated interfaces in their own project as the "interface". For other Java services and even android these

I write web services in enterprise Java using JAXRS annotated interfaces in their own project as the "interface". For other Java services and even android these jars can be shared directly and used as web clients. There are some great plug-ins out there that generate documentation and also typescript clients for node or browser environments (as well as many other languages). You get all the benefits of strong typing everywhere and only have to write the code once.