[erdeszt]

Do you mean type parameters or regular parameters? If it's the former(and Scala is allowed) then I think Rho's Result type is a pretty good bet with it's ~60 type arguments: https://github.com/http4s/rho/blob/989db04e6dd828518770a42fd...

[nkkollaw]

Ugh, why would they do that?

[lmm]

Looks like the type tells you which HTTP status codes are possible from a given route, so that e.g. a route that can return only 200 or 403 is a different type from a route that could return 302. Which makes a lot of sense, because certain transformations / routing directives that you might want to do only make sense for particular HTTP status codes.