Waitra is a very simple router. It's useful for writing simple API web-services, when you don't want to use the whole Yesod stack.
echoRoute :: Route
echoRoute = routeGet (echoApp <$ string "/api/echo/" <*> many anySym)
where echoApp msg _req respond = respond $ responseLBS status200 [] (fromString msg)
app :: Application
app = waitraMiddleware [echoRoute] $ staticApp $ embeddedSettings $(mkRecursiveEmbedded "static")
Documentation is available at hackage.