For simple or temporary projects I’d use the easy way to go (ServeMux, gorilla/mux, …), since the risk is not relevant and requirements are few. Between the well tested and popular routers instead, I’d choose Chi, because it’s light, stdlib friendly, clean, actively maintained and if you want you can also import and use all the other components. httprouter is great and a bit more performant than chi, but it seems, at least from what I see, that it’s also be on the same way as gorilla about GitHub activity, and I don’t like having this risk at all when I think about starting a new project that will possibly be in production for a long time.
Speaking about websocket I’m not convinced about others resources and if I had to need it now, I would still use gorilla, I think…