Hello @hlship, me again studying #C0K65B20P https://github.com/pedestal/pedestal.ions/blob/0.1.3/src/io/pedestal/ions.clj#L162, from pedestal ions, returns a function (a ring handler) If we use the ion-provider in a pedestal https://github.com/pedestal/pedestal-ions-sample/blob/master/src/ion_sample/service.clj#L176 and call https://github.com/pedestal/pedestal-ions-sample/blob/master/src/ion_sample/ion.clj#L26, it will return a https://github.com/pedestal/pedestal-ions-sample/blob/master/src/ion_sample/ion.clj#L59-L65 Ok, I know that pedestal.ions don't have a server But inside https://github.com/pedestal/pedestal/blob/master/service/src/io/pedestal/http.clj#L453 we call server function in the return of create-provider So: • create-provider should return a service-map, not a function as pedestal.ions does (bug in pedestal.ions)