Hello, As an experiment I modified the hamlet demo to use happstack. Was pretty trivial. I just added, -- happstack changes main :: IO () main = simpleHTTP nullConf $ liftIO $ hamletToResponse renderUrls $ template person hamletToResponse :: (Monad m) => (url -> String) -> Hamlet url m () -> m Response hamletToResponse showFn hamlet = do msg <- hamletToText showFn hamlet return $ toResponse_ (B.pack "text/html; charset=UTF-8") (T.encodeUtf8 msg) toResponse_ :: B.ByteString -> L.ByteString -> Response toResponse_ contentType message = let res = Response 200 M.empty nullRsFlags message Nothing in setHeaderBS (B.pack "Content-Type") contentType res The toResponse_ function really belongs in happstack anyway. I am going to add that right now. Normally we would add a ToMessage instance, so you could do: simpleHTTP nullConf $ template person But that won't work for two reasons: 1. we would need a way to pass in the (url -> String) function 2. the toResponse type signature does not allow for the monadic requirements of hamletToText But that is really just an issue with ToMessage class (and why I don't really like that type class much). I would like to make hamletToResponse (or something similar) available to happstack users. I think I probably need to make a new package, happstack-hamlet, to stick it in. I wonder if there is anything else useful that could go in there. I could add some additional instances, such as: mapHamlet :: forall a b url m n. (Monad m) => (m a -> m b) -> Hamlet url m a -> Hamlet url m b mapHamlet f m = Hamlet $ \showFn seed iteratee -> f' (runHamlet m showFn seed iteratee) where f' :: m (Either seed (a, seed)) -> m (Either seed (b, seed)) f' m = do e <- m case e of (Left s) -> return (Left s) (Right (a, seed)) -> do b <- f (return a) return (Right (b, seed)) instance (ServerMonad m) => ServerMonad (Hamlet url m) where askRq = liftHamlet askRq localRq f = mapHamlet (localRq f) instance (FilterMonad r m) => FilterMonad r (Hamlet url m) where setFilter = liftHamlet . setFilter composeFilter = liftHamlet . composeFilter getFilter = mapHamlet getFilter instance (WebMonad a m) => WebMonad a (Hamlet url m) where finishWith = liftHamlet . finishWith So that you could use some of the functionality of the ServerMonad, etc, in your Hamlet templates. But I am not clear how that would be useful yet. - jeremy Anyway, the full code is attached.