This library lets you automatically derive Haskell functions that let you query each endpoint of a servant webservice.
type MyApi = "books" :> Get '[JSON] [Book] -- GET /books
:<|> "books" :> ReqBody Book :> Post '[JSON] Book -- POST /books
myApi :: Proxy MyApi
myApi = Proxy
getAllBooks :: EitherT String IO [Book]
postNewBook :: Book -> EitherT String IO Book
-- 'client' allows you to produce operations to query an API from a client.
(getAllBooks :<|> postNewBook) = client myApi host
where host = BaseUrl Http "localhost" 8080