Do you want to do some complex routing based on it or just dispatch to different handlers per content type?

dispatch to different handlers per "Accept" type

In that case I'd create a multimethod which dispatches in it as the handler. Reitit only routes based on path afaik

you can also add :accept key to route data, create a ring-router out of the routes, ask the flattened route tree, group by :accept, and create separate subrouter out of each. Then create a ring-handler that looks for accept and forwards to the correct sub-router. E.g. one router per defined :accept.

At least one superfast (Go) router groups by request-method for performance.

.. same can be done in a middleware, to select a handler based on accept

if you use middleware compilation, the perf penalty is one hash-lookup. Unless you use regexs

Thanks. I think I will choose the middleware approach in my use case.