Sorry, didn't see you reply ;-) Depends on the app you're building. For a simple RESTful API, 10 lines are enough : setupApp() { this.app.use(cors()); this.app.use(bodyParser.json()); this.app.use(bodyParser.urlencoded({extended: false})); this.app.use(authUser(this)); this.app.use((req, res, next) => { req.db = this.db; req.config = this.config; next(); });

I tried Koa, Hapi, Restify but finally came back Express. It has the most mature community and is very robust.

Thank you very much for this comprehensive post! The specific use case that made me ask this question is a RESTful API I am working on. It has several generic services that can be mapped to different endpoints assets => /medias assets => /documents docs => /articles users => /employees etc. => /etc I need to tell my clients which endpoint is which service, for instance, that /medias is an assets service. I was also very curious to see how native english speakers would differentiate "kind" and "type" in code.

Algorithms have to be unit tested. Everything else is biased... by network problems, data inconsistency, unexpected user behavior, platform dependent features, unit test obsolescence. Truth is the developer will always try to test what he/she thinks should be working and turns unit tests into a discard argument and an excuse for misconceptions.