I've been using the standard library, httptreemux and Chi, depending on how large the project is. I have also used Gorilla in the past, and sometimes use Alice

I've been using the standard library, httptreemux and Chi, depending on how large the project is. I have also used Gorilla in the past, and sometimes use Alice to compose handlers. I prefer to stay close to the standard library, so as to not get stuck with code that depends too heavily on a third library with no easy way to entangle that dependency. I've still got nightmares from late '90s PHP and early 2000 Zope framework disasters... not with a 10 foot pole. Though when your application gets bigger, it makes sense to pull in a good library for some route grouping and helper functions – there are so many options, it's not worth your while to roll your own. And unless you have very specific requirements, the performance is probably not a relevant concern in a real application either.