diff --git a/src/proto_alpha/lib_baking/client_baking_commands.ml b/src/proto_alpha/lib_baking/client_baking_commands.ml
index d30b39650..020bf102f 100644
--- a/src/proto_alpha/lib_baking/client_baking_commands.ml
+++ b/src/proto_alpha/lib_baking/client_baking_commands.ml
@@ -30,13 +30,12 @@ let commands () =
          iter_s (fun d -> Client_keys.get_key cctxt d >>|? fun _ -> ()) delegates >>=? fun () ->
          run_daemon cctxt ?max_priority ~endorsement_delay ~endorsement ~baking ~denunciation delegates) ;
     command ~group ~desc: "Forge and inject an endorsement operation."
-      (args1 max_priority_arg)
+      no_options
       (prefixes [ "endorse"; "for" ]
        @@ Client_keys.Public_key_hash.source_param
          ~name:"baker" ~desc: "name of the delegate owning the endorsement right"
        @@ stop)
-      (fun max_priority delegate cctxt ->
-         endorse_block cctxt ?max_priority delegate) ;
+      (fun () delegate cctxt -> endorse_block cctxt delegate) ;
     command ~group ~desc: "Forge and inject block using the delegate rights."
       (args4 max_priority_arg force_switch
          free_baking_switch minimal_timestamp_switch)
diff --git a/src/proto_alpha/lib_baking/client_baking_endorsement.ml b/src/proto_alpha/lib_baking/client_baking_endorsement.ml
index 72a230636..44bc880ce 100644
--- a/src/proto_alpha/lib_baking/client_baking_endorsement.ml
+++ b/src/proto_alpha/lib_baking/client_baking_endorsement.ml
@@ -82,14 +82,14 @@ end = struct
 
 end
 
-let get_signing_slots cctxt ?max_priority ?(chain = `Main) block delegate level =
-  Alpha_services.Delegate.Endorser.rights_for_delegate cctxt
-    ?max_priority ~first_level:level ~last_level:level
-    (chain, block) delegate >>=? fun possibilities ->
-  let slots =
-    List.map (fun (_,slot) -> slot)
-    @@ List.filter (fun (l, _) -> l = level) possibilities in
-  return slots
+let get_signing_slots cctxt ?(chain = `Main) block delegate level =
+  Alpha_services.Delegate.Endorsing_rights.get cctxt
+    ~levels:[level]
+    ~delegates:[delegate]
+    (chain, block) >>=? fun possibilities ->
+  match possibilities with
+  | [{ slots }] -> return slots
+  | _ -> return []
 
 let inject_endorsement
     (cctxt : #Proto_alpha.full)
@@ -130,7 +130,7 @@ let check_endorsement cctxt level slot =
 
 let forge_endorsement (cctxt : #Proto_alpha.full)
     ?(chain = `Main) block
-    ~src_sk ?slots ?max_priority src_pk =
+    ~src_sk ?slots src_pk =
   let src_pkh = Signature.Public_key.hash src_pk in
   Block_services.Metadata.protocol_data
     cctxt ~chain ~block () >>=? fun { level = { level } } ->
@@ -139,7 +139,7 @@ let forge_endorsement (cctxt : #Proto_alpha.full)
     | Some slots -> return slots
     | None ->
         get_signing_slots
-          cctxt ?max_priority ~chain block src_pkh level >>=? function
+          cctxt ~chain block src_pkh level >>=? function
         | [] -> cctxt#error "No slot found at level %a" Raw_level.pp level
         | slots -> return slots
   end >>=? fun slots ->
diff --git a/src/proto_alpha/lib_baking/client_baking_endorsement.mli b/src/proto_alpha/lib_baking/client_baking_endorsement.mli
index 8262f2745..c2e862584 100644
--- a/src/proto_alpha/lib_baking/client_baking_endorsement.mli
+++ b/src/proto_alpha/lib_baking/client_baking_endorsement.mli
@@ -16,7 +16,6 @@ val forge_endorsement:
   Block_services.block ->
   src_sk:Client_keys.sk_uri ->
   ?slots:int list ->
-  ?max_priority:int ->
   public_key ->
   Operation_hash.t tzresult Lwt.t
 
diff --git a/src/proto_alpha/lib_baking/client_baking_forge.ml b/src/proto_alpha/lib_baking/client_baking_forge.ml
index ecbcc1aaf..489d45fc8 100644
--- a/src/proto_alpha/lib_baking/client_baking_forge.ml
+++ b/src/proto_alpha/lib_baking/client_baking_forge.ml
@@ -153,15 +153,15 @@ let forge_block cctxt ?(chain = `Main) block
     | `Set priority -> begin
         Alpha_services.Helpers.minimal_time
           cctxt (chain, block) ~priority >>=? fun time ->
-        return (priority, time)
+        return (priority, Some time)
       end
     | `Auto (src_pkh, max_priority, free_baking) ->
         Alpha_services.Helpers.next_level cctxt (chain, block) >>=? fun { level } ->
-        Alpha_services.Delegate.Baker.rights_for_delegate cctxt
+        Alpha_services.Delegate.Baking_rights.get cctxt
           ?max_priority
-          ~first_level:level
-          ~last_level:level
-          (chain, block) src_pkh >>=? fun possibilities ->
+          ~levels:[level]
+          ~delegates:[src_pkh]
+          (chain, block)  >>=? fun possibilities ->
         try
           begin
             if free_baking then
@@ -169,8 +169,12 @@ let forge_block cctxt ?(chain = `Main) block
             else
               return 0
           end >>=? fun min_prio ->
-          let _, prio, time =
-            List.find (fun (l,p,_) -> l = level && p >= min_prio) possibilities in
+          let { Alpha_services.Delegate.Baking_rights.priority = prio ;
+                timestamp = time } =
+            List.find
+              (fun (p : Alpha_services.Delegate.Baking_rights.t) ->
+                 p.level = level && p.priority >= min_prio)
+              possibilities in
           return (prio, time)
         with Not_found ->
           failwith "No slot found at level %a" Raw_level.pp level
@@ -179,8 +183,10 @@ let forge_block cctxt ?(chain = `Main) block
   (* Raw_level.pp level priority >>= fun () -> *)
   begin
     match timestamp, minimal_timestamp with
-    | None, timestamp -> return timestamp
-    | Some timestamp, minimal_timestamp ->
+    | None, None -> return (Time.now ())
+    | None, Some timestamp -> return timestamp
+    | Some timestamp, None -> return timestamp
+    | Some timestamp, Some minimal_timestamp ->
         if timestamp < minimal_timestamp then
           failwith
             "Proposed timestamp %a is earlier than minimal timestamp %a"
@@ -325,29 +331,22 @@ let get_baking_slot cctxt
   let chain = `Hash bi.chain_id in
   let block = `Hash (bi.hash, 0) in
   let level = Raw_level.succ bi.level.level in
-  Lwt_list.filter_map_p
-    (fun delegate ->
-       Alpha_services.Delegate.Baker.rights_for_delegate cctxt
-         ?max_priority
-         ~first_level:level
-         ~last_level:level
-         (chain, block) delegate >>= function
-       | Error errs ->
-           log_error "Error while fetching baking possibilities:\n%a"
-             pp_print_error errs ;
-           Lwt.return_none
-       | Ok slots ->
-           let convert = fun (_lvl, slot, timestamp) ->
-             (timestamp, (bi, slot, delegate)) in
-           Lwt.return (Some (List.map convert slots)))
-    delegates >>= fun slots ->
-  let sorted_slots =
-    List.sort
-      (fun (t1,_) (t2,_) -> Time.compare t1 t2)
-      (List.flatten slots) in
-  match sorted_slots with
-  | [] -> Lwt.return None
-  | slot :: _ -> Lwt.return (Some slot)
+  Alpha_services.Delegate.Baking_rights.get cctxt
+    ?max_priority
+    ~levels:[level]
+    ~delegates
+    (chain, block) >>= function
+  | Error errs ->
+      log_error "Error while fetching baking possibilities:\n%a"
+        pp_print_error errs ;
+      Lwt.return_none
+  | Ok [] ->
+      Lwt.return_none
+  | Ok ((slot : Alpha_services.Delegate.Baking_rights.t) :: _) ->
+      match slot.timestamp with
+      | None -> Lwt.return_none
+      | Some timestamp ->
+          Lwt.return_some (timestamp, (bi, slot.priority, slot.delegate))
 
 let rec insert_baking_slot slot = function
   | [] -> [slot]
diff --git a/src/proto_alpha/lib_baking/client_baking_lib.ml b/src/proto_alpha/lib_baking/client_baking_lib.ml
index 9d3991c9a..be1413a47 100644
--- a/src/proto_alpha/lib_baking/client_baking_lib.ml
+++ b/src/proto_alpha/lib_baking/client_baking_lib.ml
@@ -44,10 +44,10 @@ let bake_block (cctxt : #Proto_alpha.full)
   cctxt#message "Injected block %a" Block_hash.pp_short block_hash >>= fun () ->
   return ()
 
-let endorse_block cctxt ?max_priority delegate =
+let endorse_block cctxt delegate =
   Client_keys.get_key cctxt delegate >>=? fun (_src_name, src_pk, src_sk) ->
   Client_baking_endorsement.forge_endorsement cctxt
-    cctxt#block ?max_priority ~src_sk src_pk >>=? fun oph ->
+    cctxt#block ~src_sk src_pk >>=? fun oph ->
   cctxt#answer "Operation successfully injected in the node." >>= fun () ->
   cctxt#answer "Operation hash is '%a'." Operation_hash.pp oph >>= fun () ->
   return ()
diff --git a/src/proto_alpha/lib_baking/client_baking_lib.mli b/src/proto_alpha/lib_baking/client_baking_lib.mli
index 4da34232c..373867783 100644
--- a/src/proto_alpha/lib_baking/client_baking_lib.mli
+++ b/src/proto_alpha/lib_baking/client_baking_lib.mli
@@ -26,7 +26,6 @@ val bake_block:
 (** Endorse a block *)
 val endorse_block:
   #Proto_alpha.full ->
-  ?max_priority:int ->
   Client_keys.Public_key_hash.t ->
   unit Error_monad.tzresult Lwt.t
 
diff --git a/src/proto_alpha/lib_baking/test/proto_alpha_helpers.ml b/src/proto_alpha/lib_baking/test/proto_alpha_helpers.ml
index 1fadc7772..d9de9fd1d 100644
--- a/src/proto_alpha/lib_baking/test/proto_alpha_helpers.ml
+++ b/src/proto_alpha/lib_baking/test/proto_alpha_helpers.ml
@@ -560,17 +560,14 @@ module Endorse = struct
     sign ~watermark:Endorsement src_sk shell contents
 
   let signing_slots
-      ?(max_priority = 1024)
       block
       delegate
       level =
-    Alpha_services.Delegate.Endorser.rights_for_delegate
-      !rpc_ctxt ~max_priority ~first_level:level ~last_level:level
-      (`Main, block) delegate >>=? fun possibilities ->
-    let slots =
-      List.map (fun (_,slot) -> slot)
-      @@ List.filter (fun (l, _) -> l = level) possibilities in
-    return slots
+    Alpha_services.Delegate.Endorsing_rights.get
+      !rpc_ctxt ~delegates:[delegate] ~levels:[level]
+      (`Main, block) >>=? function
+    | [{ slots }] -> return slots
+    | _ -> return []
 
   let endorse
       ?slot
@@ -596,15 +593,15 @@ module Endorse = struct
   (* FIXME @vb: I don't understand this function, copied from @cago. *)
   let endorsers_list block =
     let get_endorser_list result (account : Account.t) level block =
-      Alpha_services.Delegate.Endorser.rights_for_delegate
-        !rpc_ctxt (`Main, block) account.pkh
-        ~max_priority:16
-        ~first_level:level
-        ~last_level:level >>|? fun slots ->
-      List.iter (fun (_,slot) -> result.(slot) <- account) slots
-    in
+      Alpha_services.Delegate.Endorsing_rights.get
+        !rpc_ctxt (`Main, block)
+        ~delegates:[account.pkh]
+        ~levels:[level] >>|? function
+      | [{ slots }] ->
+          List.iter (fun s -> result.(s) <- account) slots
+      | _ -> () in
     let { Account.b1 ; b2 ; b3 ; b4 ; b5 } = Account.bootstrap_accounts in
-    let result = Array.make 16 b1 in
+    let result = Array.make 32 b1 in
     Block_services.Metadata.protocol_data
       !rpc_ctxt ~chain:`Main ~block () >>=? fun { level } ->
     let level = level.level in
@@ -616,18 +613,18 @@ module Endorse = struct
     return result
 
   let endorsement_rights
-      ?(max_priority = 1024)
       (contract : Account.t) block =
     Block_services.Metadata.protocol_data
       !rpc_ctxt ~chain:`Main ~block () >>=? fun { level } ->
     let level = level.level in
     let delegate = contract.pkh in
-    Alpha_services.Delegate.Endorser.rights_for_delegate
+    Alpha_services.Delegate.Endorsing_rights.get
       !rpc_ctxt
-      ~max_priority
-      ~first_level:level
-      ~last_level:level
-      (`Main, block) delegate
+      ~levels:[level]
+      ~delegates:[delegate]
+      (`Main, block) >>=? function
+    | [{ level ; slots }] -> return (List.map (fun s -> (level, s)) slots)
+    | _ -> return []
 
 end
 
diff --git a/src/proto_alpha/lib_baking/test/proto_alpha_helpers.mli b/src/proto_alpha/lib_baking/test/proto_alpha_helpers.mli
index 750ddcbd5..53d95bc40 100644
--- a/src/proto_alpha/lib_baking/test/proto_alpha_helpers.mli
+++ b/src/proto_alpha/lib_baking/test/proto_alpha_helpers.mli
@@ -122,7 +122,6 @@ module Endorse : sig
     Account.t array tzresult Lwt.t
 
   val endorsement_rights :
-    ?max_priority:int ->
     Account.t ->
     Block_services.block ->
     (Raw_level.t * int) list tzresult Lwt.t
diff --git a/src/proto_alpha/lib_protocol/src/apply.ml b/src/proto_alpha/lib_protocol/src/apply.ml
index 3ca7f1514..5fbe59291 100644
--- a/src/proto_alpha/lib_protocol/src/apply.ml
+++ b/src/proto_alpha/lib_protocol/src/apply.ml
@@ -352,9 +352,10 @@ let apply_consensus_operation_content ctxt
       Operation.check_signature delegate operation >>=? fun () ->
       let delegate = Signature.Public_key.hash delegate in
       let ctxt = Fitness.increase ~gap:(List.length slots) ctxt in
-      Baking.freeze_endorsement_deposit ctxt delegate >>=? fun ctxt ->
+      Baking.freeze_endorsement_deposit
+        ctxt delegate (List.length slots) >>=? fun ctxt ->
       Global.get_last_block_priority ctxt >>=? fun block_priority ->
-      Baking.endorsement_reward ctxt ~block_priority >>=? fun reward ->
+      Baking.endorsement_reward ctxt ~block_priority (List.length slots) >>=? fun reward ->
       Delegate.freeze_rewards ctxt delegate reward >>=? fun ctxt ->
       return (ctxt, Endorsements_result (delegate, slots))
 
diff --git a/src/proto_alpha/lib_protocol/src/baking.ml b/src/proto_alpha/lib_protocol/src/baking.ml
index 18ecf5cd3..5de61ea40 100644
--- a/src/proto_alpha/lib_protocol/src/baking.ml
+++ b/src/proto_alpha/lib_protocol/src/baking.ml
@@ -151,6 +151,18 @@ let minimal_time c priority pred_timestamp =
     (cumsum_time_between_blocks
        pred_timestamp (Constants.time_between_blocks c) (Int32.succ priority))
 
+let earlier_predecessor_timestamp ctxt level =
+  let current = Level.current ctxt in
+  let current_timestamp = Timestamp.current ctxt in
+  let gap = Level.diff level current in
+  let step = List.hd (Constants.time_between_blocks ctxt) in
+  if Compare.Int32.(gap < 1l) then
+    failwith "Baking.earlier_block_timestamp: past block."
+  else
+    Lwt.return (Period.mult (Int32.pred gap) step) >>=? fun delay ->
+    Lwt.return Timestamp.(current_timestamp +? delay) >>=? fun result ->
+    return result
+
 let freeze_baking_deposit ctxt { Block_header.priority ; _ } delegate =
   if Compare.Int.(priority >= Constants.first_free_baking_slot ctxt)
   then return (ctxt, Tez.zero)
@@ -160,8 +172,9 @@ let freeze_baking_deposit ctxt { Block_header.priority ; _ } delegate =
     |> trace Cannot_freeze_baking_deposit >>=? fun ctxt ->
     return (ctxt, deposit)
 
-let freeze_endorsement_deposit ctxt delegate =
+let freeze_endorsement_deposit ctxt delegate n =
   let deposit = Constants.endorsement_security_deposit ctxt in
+  Lwt.return (Tez.(deposit *? Int64.of_int n)) >>=? fun deposit ->
   Delegate.freeze_deposit ctxt delegate deposit
   |> trace Cannot_freeze_endorsement_deposit
 
@@ -196,11 +209,12 @@ let paying_priorities c =
 
 type error += Incorrect_priority
 
-let endorsement_reward ctxt ~block_priority:prio =
+let endorsement_reward ctxt ~block_priority:prio n =
   if Compare.Int.(prio >= 0)
   then
     Lwt.return
-      Tez.(Constants.endorsement_reward ctxt /? (Int64.(succ (of_int prio))))
+      Tez.(Constants.endorsement_reward ctxt /? (Int64.(succ (of_int prio)))) >>=? fun tez ->
+    Lwt.return Tez.(tez *? Int64.of_int n)
   else fail Incorrect_priority
 
 let baking_priorities c level =
diff --git a/src/proto_alpha/lib_protocol/src/baking.mli b/src/proto_alpha/lib_protocol/src/baking.mli
index 84e207c3e..714b72365 100644
--- a/src/proto_alpha/lib_protocol/src/baking.mli
+++ b/src/proto_alpha/lib_protocol/src/baking.mli
@@ -50,7 +50,7 @@ val freeze_baking_deposit:
     Raise an error if the baker account does not have enough
     funds to claim endorsement rights *)
 val freeze_endorsement_deposit:
-  context -> public_key_hash -> context tzresult Lwt.t
+  context -> public_key_hash -> int -> context tzresult Lwt.t
 
 (** [check_baking_rights ctxt block pred_timestamp] verifies that:
     * the contract that owned the roll at cycle start has the block signer as delegate.
@@ -69,7 +69,7 @@ val check_endorsements_rights:
   context -> Level.t -> int list -> public_key tzresult Lwt.t
 
 (** Returns the endorsement reward calculated w.r.t a given priotiry.  *)
-val endorsement_reward: context -> block_priority:int -> Tez.t tzresult Lwt.t
+val endorsement_reward: context -> block_priority:int -> int -> Tez.t tzresult Lwt.t
 
 (** [baking_priorities ctxt level] is the lazy list of contract's
     public key hashes that are allowed to bake for [level]. *)
@@ -120,3 +120,5 @@ val check_fitness_gap:
   context -> Block_header.t -> unit tzresult Lwt.t
 
 val dawn_of_a_new_cycle: context -> Cycle.t option tzresult Lwt.t
+
+val earlier_predecessor_timestamp: context -> Level.t -> Timestamp.t tzresult Lwt.t
diff --git a/src/proto_alpha/lib_protocol/src/delegate_services.ml b/src/proto_alpha/lib_protocol/src/delegate_services.ml
index 22d8e605e..c5e9e4dff 100644
--- a/src/proto_alpha/lib_protocol/src/delegate_services.ml
+++ b/src/proto_alpha/lib_protocol/src/delegate_services.ml
@@ -9,13 +9,6 @@
 
 open Alpha_context
 
-let slots_range_encoding =
-  let open Data_encoding in
-  (obj3
-     (opt "max_priority" int31)
-     (opt "first_level" Raw_level.encoding)
-     (opt "last_level" Raw_level.encoding))
-
 type info = {
   balance: Tez.t ;
   frozen_balance: Tez.t ;
@@ -38,13 +31,13 @@ let info_encoding =
       { balance ; frozen_balance ; frozen_balances ; delegated_balance ;
         delegated_contracts ; deactivated ; grace_period })
     (obj7
-      (req "balance" Tez.encoding)
-      (req "frozen_balance" Tez.encoding)
-      (req "frozen_balances" Delegate.frozen_balances_encoding)
-      (req "delegated_balance" Tez.encoding)
-      (req "delegated_contracts" (list Contract_hash.encoding))
-      (req "deactivated" bool)
-      (req "grace_period" Cycle.encoding))
+       (req "balance" Tez.encoding)
+       (req "frozen_balance" Tez.encoding)
+       (req "frozen_balances" Delegate.frozen_balances_encoding)
+       (req "delegated_balance" Tez.encoding)
+       (req "delegated_contracts" (list Contract_hash.encoding))
+       (req "deactivated" bool)
+       (req "grace_period" Cycle.encoding))
 
 module S = struct
 
@@ -230,313 +223,264 @@ let deactivated ctxt block pkh =
 let grace_period ctxt block pkh =
   RPC_context.make_call1 S.grace_period ctxt block pkh () ()
 
+let requested_levels ~default ctxt cycles levels =
+  match levels, cycles with
+  | [], [] ->
+      return [default]
+  | levels, cycles ->
+      (* explicitly fail when requested levels or cycle are in the past...
+         or too far in the future... *)
+      (* check_levels levels >>=? fun () -> *)
+      (* check_cycles levels >>=? fun () -> *)
+      let levels =
+        List.sort_uniq
+          Level.compare
+          (List.concat (List.map (Level.from_raw ctxt) levels ::
+                        List.map (Level.levels_in_cycle ctxt) cycles)) in
+      map_p
+        (fun level ->
+           let current_level = Level.current ctxt in
+           if Level.(level <= current_level) then
+             return (level, None)
+           else
+             Baking.earlier_predecessor_timestamp
+               ctxt level >>=? fun timestamp ->
+             return (level, Some timestamp))
+        levels
 
-module Baker = struct
+module Baking_rights = struct
+
+  type t = {
+    level: Raw_level.t ;
+    delegate: Signature.Public_key_hash.t ;
+    priority: int ;
+    timestamp: Timestamp.t option ;
+  }
+
+  let encoding =
+    let open Data_encoding in
+    conv
+      (fun { level ; delegate ; priority ; timestamp } ->
+         (level, delegate, priority, timestamp))
+      (fun (level, delegate, priority, timestamp) ->
+         { level ; delegate ; priority ; timestamp })
+      (obj4
+         (req "level" Raw_level.encoding)
+         (req "delegate" Signature.Public_key_hash.encoding)
+         (req "priority" uint16)
+         (opt "timestamp" Timestamp.encoding))
 
   module S = struct
 
     open Data_encoding
 
     let custom_root =
-      RPC_path.(open_root / "helpers" / "rights" / "baking")
+      RPC_path.(open_root / "helpers" / "baking_rights")
 
-    let slot_encoding =
-      (obj3
-         (req "level" Raw_level.encoding)
-         (req "priority" int31)
-         (req "timestamp" Timestamp.encoding))
+    type baking_rights_query = {
+      levels: Raw_level.t list ;
+      cycles: Cycle.t list ;
+      delegates: Signature.Public_key_hash.t list ;
+      max_priority: int option ;
+      all: bool ;
+    }
 
-    let rights =
-      RPC_service.post_service
-        ~description:
-          "List delegates allowed to bake for the next level, \
-           ordered by priority."
-        ~query: RPC_query.empty
-        ~input: (obj1 (opt "max_priority" int31))
-        ~output: (obj2
-                    (req "level" Raw_level.encoding)
-                    (req "baking_rights"
-                       (list
-                          (obj2
-                             (req "delegate" Signature.Public_key_hash.encoding)
-                             (req "timestamp" Timestamp.encoding)))))
+    let baking_rights_query =
+      let open RPC_query in
+      query (fun levels cycles delegates max_priority all ->
+          { levels ; cycles ; delegates ; max_priority ; all })
+      |+ multi_field "level" Raw_level.arg (fun t -> t.levels)
+      |+ multi_field "cycle" Cycle.arg (fun t -> t.cycles)
+      |+ multi_field "delegate" Signature.Public_key_hash.rpc_arg (fun t -> t.delegates)
+      |+ opt_field "max_priority" RPC_arg.int (fun t -> t.max_priority)
+      |+ flag "all" (fun t -> t.all)
+      |> seal
+
+    let baking_rights =
+      RPC_service.get_service
+        ~description: "...FIXME..."
+        ~query: baking_rights_query
+        ~output: (list encoding)
         custom_root
 
-    let rights_for_level =
-      RPC_service.post_service
-        ~description:
-          "List delegates allowed to bake for a given level, \
-           ordered by priority."
-        ~query: RPC_query.empty
-        ~input: (obj1 (opt "max_priority" int31))
-        ~output: (obj2
-                    (req "level" Raw_level.encoding)
-                    (req "delegates"
-                       (list Signature.Public_key_hash.encoding)))
-        RPC_path.(custom_root / "level" /: Raw_level.arg)
-
-    (* let levels = *)
-    (* RPC_service.post_service *)
-    (* ~description: *)
-    (* "List level for which we might computed baking rights." *)
-    (* ~query: RPC_query.empty *)
-    (* ~input: empty *)
-    (* ~output: (obj1 (req "levels" (list Raw_level.encoding))) *)
-    (* RPC_path.(custom_root / "level") *)
-
-    let rights_for_delegate =
-      RPC_service.post_service
-        ~description: "Future baking rights for a given delegate."
-        ~query: RPC_query.empty
-        ~input: slots_range_encoding
-        ~output: (Data_encoding.list slot_encoding)
-        RPC_path.(custom_root / "delegate" /: Signature.Public_key_hash.rpc_arg)
-
-
-    (* let delegates = *)
-    (* RPC_service.post_service *)
-    (* ~description: *)
-    (* "List delegates with baking rights." *)
-    (* ~query: RPC_query.empty *)
-    (* ~input: empty *)
-    (* ~output: (obj1 (req "delegates" *)
-    (* (list Signature.Public_key_hash.encoding))) *)
-    (* RPC_path.(custom_root / "delegate") *)
-
   end
 
-  module I = struct
+  let baking_priorities ctxt max_prio (level, pred_timestamp) =
+    Baking.baking_priorities ctxt level >>=? fun contract_list ->
+    let rec loop l acc priority =
+      if Compare.Int.(priority >= max_prio) then
+        return (List.rev acc)
+      else
+        let Misc.LCons (pk, next) = l in
+        let delegate = Signature.Public_key.hash pk in
+        begin
+          match pred_timestamp with
+          | None -> return None
+          | Some pred_timestamp ->
+              Baking.minimal_time ctxt priority pred_timestamp >>=? fun t ->
+              return (Some t)
+        end>>=? fun timestamp ->
+        let acc =
+          { level = level.level ; delegate ; priority ; timestamp } :: acc in
+        next () >>=? fun l ->
+        loop l acc (priority+1) in
+    loop contract_list [] 0
 
-    let default_max_baking_priority ctxt arg =
-      let default = Constants.first_free_baking_slot ctxt in
-      match arg with
-      | None -> 2 * default
-      | Some m -> m
-
-    let baking_rights_for_level ctxt level max =
-      let max = default_max_baking_priority ctxt max in
-      Baking.baking_priorities ctxt level >>=? fun contract_list ->
-      let rec loop l n =
-        match n with
-        | 0 -> return []
-        | n ->
-            let Misc.LCons (h, t) = l in
-            t () >>=? fun t ->
-            loop t (pred n) >>=? fun t ->
-            return (Signature.Public_key.hash h :: t)
-      in
-      loop contract_list max >>=? fun prio ->
-      return (level.level, prio)
-
-    let baking_rights ctxt () max =
-      let level = Level.succ ctxt (Level.current ctxt) in
-      baking_rights_for_level ctxt level max >>=? fun (raw_level, slots) ->
-      begin
-        Lwt_list.filter_map_p (fun x -> x) @@
-        List.mapi
-          (fun prio c ->
-             let timestamp = Timestamp.current ctxt in
-             Baking.minimal_time ctxt prio timestamp >>= function
-             | Error _ -> Lwt.return None
-             | Ok minimal_timestamp -> Lwt.return (Some (c, minimal_timestamp)))
-          slots
-      end >>= fun timed_slots ->
-      return (raw_level, timed_slots)
-
-    let baking_rights_for_delegate
-        ctxt contract () (max_priority, min_level, max_level) =
-      let max_priority = default_max_baking_priority ctxt max_priority in
-      let current_level = Level.succ ctxt (Level.current ctxt) in
-      let min_level = match min_level with
-        | None -> current_level
-        | Some l -> Level.from_raw ctxt l in
-      let max_level =
-        match max_level with
-        | Some max_level -> Level.from_raw ctxt max_level
-        | None ->
-            Level.last_level_in_cycle ctxt @@
-            current_level.cycle in
-      let rec loop level =
-        if Level.(>) level max_level
-        then return []
-        else
-          loop (Level.succ ctxt level) >>=? fun t ->
-          Baking.first_baking_priorities
-            ctxt ~max_priority contract level >>=? fun priorities ->
-          let raw_level = level.level in
-          Error_monad.map_s
-            (fun priority ->
-               let timestamp = Timestamp.current ctxt in
-               Baking.minimal_time ctxt priority timestamp >>=? fun time ->
-               return (raw_level, priority, time))
-            priorities >>=? fun priorities ->
-          return (priorities @ t)
-      in
-      loop min_level
-
-  end
+  let remove_duplicated_delegates rights =
+    List.rev @@ fst @@
+    List.fold_left
+      (fun (acc, previous) r ->
+         if Signature.Public_key_hash.Set.mem r.delegate previous then
+           (acc, previous)
+         else
+           (r :: acc,
+            Signature.Public_key_hash.Set.add r.delegate previous))
+      ([], Signature.Public_key_hash.Set.empty)
+      rights
 
   let () =
     let open Services_registration in
-    register0 S.rights I.baking_rights ;
-    register1 S.rights_for_level begin fun ctxt raw_level () max ->
-      let level = Level.from_raw ctxt raw_level in
-      I.baking_rights_for_level ctxt level max
-    end;
-    register1 S.rights_for_delegate I.baking_rights_for_delegate
+    register0 S.baking_rights begin fun ctxt q () ->
+      requested_levels
+        ~default:
+          (Level.succ ctxt (Level.current ctxt), Some (Timestamp.current ctxt))
+        ctxt q.cycles q.levels >>=? fun levels ->
+      let max_priority =
+        match q.max_priority with
+        | None -> 64
+        | Some max -> max in
+      map_p (baking_priorities ctxt max_priority) levels >>=? fun rights ->
+      let rights =
+        if q.all then
+          rights
+        else
+          List.map remove_duplicated_delegates rights in
+      let rights = List.concat rights in
+      match q.delegates with
+      | [] -> return rights
+      | _ :: _ as delegates ->
+          let is_requested p =
+            List.exists (Signature.Public_key_hash.equal p.delegate) delegates in
+          return (List.filter is_requested rights)
+    end
 
-  let rights ctxt ?max_priority block =
-    RPC_context.make_call0 S.rights ctxt block () max_priority
-
-  let rights_for_level ctxt ?max_priority block level =
-    RPC_context.make_call1 S.rights_for_level ctxt block level () max_priority
-
-  let rights_for_delegate ctxt ?max_priority ?first_level ?last_level block delegate =
-    RPC_context.make_call1 S.rights_for_delegate ctxt block delegate ()
-      (max_priority, first_level, last_level)
+  let get ctxt
+      ?(levels = []) ?(cycles = []) ?(delegates = []) ?(all = false)
+      ?max_priority block =
+    RPC_context.make_call0 S.baking_rights ctxt block
+      { levels ; cycles ; delegates ; max_priority ; all }
+      ()
 
 end
 
-module Endorser = struct
+module Endorsing_rights = struct
+
+  type t = {
+    level: Raw_level.t ;
+    delegate: Signature.Public_key_hash.t ;
+    slots: int list ;
+    estimated_time: Time.t option ;
+  }
+
+  let encoding =
+    let open Data_encoding in
+    conv
+      (fun { level ; delegate ; slots ; estimated_time } ->
+         (level, delegate, slots, estimated_time))
+      (fun (level, delegate, slots, estimated_time) ->
+         { level ; delegate ; slots ; estimated_time })
+      (obj4
+         (req "level" Raw_level.encoding)
+         (req "delegate" Signature.Public_key_hash.encoding)
+         (req "slots" (list uint16))
+         (opt "estimated_time" Timestamp.encoding))
 
   module S = struct
 
     open Data_encoding
 
     let custom_root =
-      RPC_path.(open_root / "helpers" / "rights" / "endorsement")
+      RPC_path.(open_root / "helpers" / "endorsing_rights")
 
-    let slot_encoding =
-      (obj2
-         (req "level" Raw_level.encoding)
-         (req "priority" int31))
+    type endorsing_rights_query = {
+      levels: Raw_level.t list ;
+      cycles: Cycle.t list ;
+      delegates: Signature.Public_key_hash.t list ;
+    }
 
-    let rights =
-      RPC_service.post_service
-        ~description:
-          "List delegates allowed to endorse for the current block."
-        ~query: RPC_query.empty
-        ~input: (obj1 (opt "max_priority" int31))
-        ~output: (obj2
-                    (req "level" Raw_level.encoding)
-                    (req "delegates"
-                       (list Signature.Public_key_hash.encoding)))
+    let endorsing_rights_query =
+      let open RPC_query in
+      query (fun levels cycles delegates ->
+          { levels ; cycles ; delegates })
+      |+ multi_field "level" Raw_level.arg (fun t -> t.levels)
+      |+ multi_field "cycle" Cycle.arg (fun t -> t.cycles)
+      |+ multi_field "delegate" Signature.Public_key_hash.rpc_arg (fun t -> t.delegates)
+      |> seal
+
+    let endorsing_rights =
+      RPC_service.get_service
+        ~description: "...FIXME..."
+        ~query: endorsing_rights_query
+        ~output: (list encoding)
         custom_root
 
-    let rights_for_level =
-      RPC_service.post_service
-        ~description:
-          "List delegates allowed to endorse blocks for a given level."
-        ~query: RPC_query.empty
-        ~input: (obj1 (opt "max_priority" int31))
-        ~output: (obj2
-                    (req "level" Raw_level.encoding)
-                    (req "delegates"
-                       (list Signature.Public_key_hash.encoding)))
-        RPC_path.(custom_root / "level" /: Raw_level.arg)
-
-    (* let levels = *)
-    (* RPC_service.post_service *)
-    (* ~description: *)
-    (* "List level for which we might computed endorsement rights." *)
-    (* ~query: RPC_query.empty *)
-    (* ~input: empty *)
-    (* ~output: (obj1 (req "levels" (list Raw_level.encoding))) *)
-    (* RPC_path.(custom_root / "level") *)
-
-    let rights_for_delegate =
-      RPC_service.post_service
-        ~description: "Compute endorsement rights for a given delegate."
-        ~query: RPC_query.empty
-        ~input: slots_range_encoding
-        ~output: (Data_encoding.list slot_encoding)
-        RPC_path.(custom_root / "delegate" /: Signature.Public_key_hash.rpc_arg)
-
-    (* let delegates = *)
-    (* RPC_service.post_service *)
-    (* ~description: *)
-    (* "List delegates with endorsement rights." *)
-    (* ~query: RPC_query.empty *)
-    (* ~input: empty *)
-    (* ~output: (obj1 (req "delegates" *)
-    (* (list Signature.Public_key_hash.encoding))) *)
-    (* RPC_path.(custom_root / "delegate") *)
-
   end
 
-  module I = struct
-
-    let default_max_endorsement_priority ctxt arg =
-      let default = Constants.endorsers_per_block ctxt in
-      match arg with
-      | None -> default
-      | Some m -> m
-
-    let endorsement_rights ctxt level max =
-      let max = default_max_endorsement_priority ctxt max in
-      Baking.endorsement_priorities ctxt level >>=? fun contract_list ->
-      let rec loop l n =
-        match n with
-        | 0 -> return []
-        | n ->
-            let Misc.LCons (h, t) = l in
-            t () >>=? fun t ->
-            loop t (pred n) >>=? fun t ->
-            return (Signature.Public_key.hash h :: t)
-      in
-      loop contract_list max >>=? fun prio ->
-      return (level.level, prio)
-
-    let endorsement_rights_for_delegate
-        ctxt contract () (max_priority, min_level, max_level) =
-      let current_level = Level.current ctxt in
-      let max_priority = default_max_endorsement_priority ctxt max_priority in
-      let min_level = match min_level with
-        | None -> current_level
-        | Some l -> Level.from_raw ctxt l in
-      let max_level =
-        match max_level with
-        | None -> min_level
-        | Some l -> Level.from_raw ctxt l in
-      let rec loop level =
-        if Level.(>) level max_level
-        then return []
-        else
-          loop (Level.succ ctxt level) >>=? fun t ->
-          Baking.first_endorsement_slots
-            ctxt ~max_priority contract level >>=? fun slots ->
-          let raw_level = level.level in
-          let slots = List.rev_map (fun slot -> (raw_level, slot)) slots in
-          return (List.rev_append slots t)
-      in
-      loop min_level
-
-  end
+  let endorsement_slots ctxt (level, estimated_time) =
+    let max_slot = Constants.endorsers_per_block ctxt in
+    Baking.endorsement_priorities ctxt level >>=? fun contract_list ->
+    let build (delegate, slots) = {
+      level = level.level ; delegate ; slots ; estimated_time
+    } in
+    let rec loop l map slot =
+      if Compare.Int.(slot >= max_slot) then
+        return (List.map build (Signature.Public_key_hash.Map.bindings map))
+      else
+        let Misc.LCons (pk, next) = l in
+        let delegate = Signature.Public_key.hash pk in
+        let slots =
+          match Signature.Public_key_hash.Map.find_opt delegate map with
+          | None -> [slot]
+          | Some slots -> slot :: slots in
+        let map = Signature.Public_key_hash.Map.add delegate slots map in
+        next () >>=? fun l ->
+        loop l map (slot+1) in
+    loop contract_list Signature.Public_key_hash.Map.empty 0
 
   let () =
     let open Services_registration in
-    register0 S.rights begin fun ctxt () max ->
-      let level = Level.current ctxt in
-      I.endorsement_rights ctxt level max
-    end ;
-    register1 S.rights_for_level begin fun ctxt raw_level () max ->
-      let level = Level.from_raw ctxt raw_level in
-      I.endorsement_rights ctxt level max
-    end ;
-    register1 S.rights_for_delegate I.endorsement_rights_for_delegate
+    register0 S.endorsing_rights begin fun ctxt q () ->
+      requested_levels
+        ~default: (Level.current ctxt, Some (Timestamp.current ctxt))
+        ctxt q.cycles q.levels >>=? fun levels ->
+      map_p (endorsement_slots ctxt) levels >>=? fun rights ->
+      let rights = List.concat rights in
+      match q.delegates with
+      | [] -> return rights
+      | _ :: _ as delegates ->
+          let is_requested p =
+            List.exists (Signature.Public_key_hash.equal p.delegate) delegates in
+          return (List.filter is_requested rights)
+    end
 
-  let rights ctxt ?max_priority block =
-    RPC_context.make_call0 S.rights ctxt block () max_priority
-
-  let rights_for_level ctxt ?max_priority block level =
-    RPC_context.make_call1 S.rights_for_level ctxt block level () max_priority
-
-  let rights_for_delegate ctxt ?max_priority ?first_level ?last_level block delegate =
-    RPC_context.make_call1 S.rights_for_delegate ctxt block delegate ()
-      (max_priority, first_level, last_level)
+  let get ctxt
+      ?(levels = []) ?(cycles = []) ?(delegates = []) block =
+    RPC_context.make_call0 S.endorsing_rights ctxt block
+      { levels ; cycles ; delegates }
+      ()
 
 end
 
+let endorsement_rights ctxt level =
+  Endorsing_rights.endorsement_slots ctxt (level, None) >>=? fun l ->
+  return (List.map (fun { Endorsing_rights.delegate ; _ } -> delegate) l)
+
+let baking_rights ctxt max_priority =
+  let max = match max_priority with None -> 64 | Some m -> m in
+  let level = Level.current ctxt in
+  Baking_rights.baking_priorities ctxt max (level, None) >>=? fun l ->
+  return (level.level,
+          List.map
+            (fun { Baking_rights.delegate ; timestamp ; _ } ->
+               (delegate, timestamp)) l)
 
-let baking_rights = Baker.I.baking_rights
-let endorsement_rights = Endorser.I.endorsement_rights
diff --git a/src/proto_alpha/lib_protocol/src/delegate_services.mli b/src/proto_alpha/lib_protocol/src/delegate_services.mli
index ae1966a0f..d9c13b9c5 100644
--- a/src/proto_alpha/lib_protocol/src/delegate_services.mli
+++ b/src/proto_alpha/lib_protocol/src/delegate_services.mli
@@ -68,50 +68,73 @@ val grace_period:
   Cycle.t shell_tzresult Lwt.t
 
 
-module Baker : sig
+module Baking_rights : sig
 
-  val rights:
-    'a #RPC_context.simple -> ?max_priority:int -> 'a ->
-    (Raw_level.t * (Signature.Public_key_hash.t * Time.t) list) shell_tzresult Lwt.t
+  type t = {
+    level: Raw_level.t ;
+    delegate: Signature.Public_key_hash.t ;
+    priority: int ;
+    timestamp: Timestamp.t option ;
+  }
 
-  val rights_for_level:
-    'a #RPC_context.simple -> ?max_priority:int -> 'a -> Raw_level.t ->
-    (Raw_level.t * Signature.Public_key_hash.t list) shell_tzresult Lwt.t
+  (** Compute the baking rights. By default, it computes the baking
+      rights for the next block and only returns the first available
+      priority for bakers that appears in the 64 first priorities.
 
-  val rights_for_delegate:
+      The optional arguments [levels] and [cycles] allows to compute
+      baking for an explicit list of levels or for all the levels of the given
+      cycles.
+
+      The optional argument [delegates] allows to filter
+      the non-explicitly listed delegates out of the resulting list.
+
+      When [all=false], the function only returns the minimal priority
+      for each delegates. When [all=true], all priorities are returned. *)
+  val get:
     'a #RPC_context.simple ->
-    ?max_priority:int -> ?first_level:Raw_level.t -> ?last_level:Raw_level.t ->
-    'a -> Signature.Public_key_hash.t ->
-    (Raw_level.t * int * Time.t) list shell_tzresult Lwt.t
+    ?levels: Raw_level.t list ->
+    ?cycles: Cycle.t list ->
+    ?delegates: Signature.public_key_hash list ->
+    ?all: bool ->
+    ?max_priority: int ->
+    'a -> t list shell_tzresult Lwt.t
 
 end
 
-module Endorser : sig
+module Endorsing_rights : sig
 
-  val rights:
-    'a #RPC_context.simple -> ?max_priority:int -> 'a ->
-    (Raw_level.t * Signature.Public_key_hash.t list) shell_tzresult Lwt.t
+  type t = {
+    level: Raw_level.t ;
+    delegate: Signature.Public_key_hash.t ;
+    slots: int list ;
+    estimated_time: Timestamp.t option ;
+  }
 
-  val rights_for_level:
-    'a #RPC_context.simple -> ?max_priority:int -> 'a -> Raw_level.t ->
-    (Raw_level.t * Signature.Public_key_hash.t list) shell_tzresult Lwt.t
+  (** Compute the endorsing rights. By default, it computes the
+      endorsing rights for the next block.
 
-  val rights_for_delegate:
+      The optional arguments [levels] and [cycles] allows to compute
+      baking for an explicit list of levels or for all the levels of
+      the given cycles.
+
+      The optional argument [delegates] allows to filter the
+      non-explicitly listed delegates out of the resulting list.. *)
+  val get:
     'a #RPC_context.simple ->
-    ?max_priority:int -> ?first_level:Raw_level.t -> ?last_level:Raw_level.t ->
-    'a -> Signature.Public_key_hash.t ->
-    (Raw_level.t * int) list shell_tzresult Lwt.t
+    ?levels: Raw_level.t list ->
+    ?cycles: Cycle.t list ->
+    ?delegates: Signature.public_key_hash list ->
+    'a -> t list shell_tzresult Lwt.t
 
 end
 
-(* temporary export *)
+(* temporary export for deprecated unit test *)
 val endorsement_rights:
   Alpha_context.t ->
   Level.t ->
-  int option -> (Raw_level.t * public_key_hash list) tzresult Lwt.t
+  public_key_hash list tzresult Lwt.t
 
 val baking_rights:
   Alpha_context.t ->
-  unit ->
   int option ->
-  (Raw_level.t * (public_key_hash * Time.t) list) tzresult Lwt.t
+  (Raw_level.t * (public_key_hash * Time.t option) list) tzresult Lwt.t
diff --git a/src/proto_alpha/lib_protocol/test/double_baking.ml b/src/proto_alpha/lib_protocol/test/double_baking.ml
index 5b291142c..2352f2bd8 100644
--- a/src/proto_alpha/lib_protocol/test/double_baking.ml
+++ b/src/proto_alpha/lib_protocol/test/double_baking.ml
@@ -30,14 +30,8 @@ let get_first_different_bakers ctxt =
 
 let get_first_different_endorsers ctxt =
   Context.get_endorsers ctxt >>=? fun endorsers ->
-  let endorsers = List.combine endorsers (0--((List.length endorsers) - 1)) in
-  let endorser_1 = List.hd endorsers in
-  let endorser_2 =
-    List.find (fun (endorser, _slot) ->
-        Signature.Public_key_hash.(<>)
-          (fst endorser_1) endorser)
-      (List.tl endorsers)
-  in
+  let endorser_1 = (List.hd endorsers).delegate in
+  let endorser_2 = (List.hd (List.tl endorsers)).delegate in
   return (endorser_1, endorser_2)
 
 (** Bake two block at the same level using the same policy (i.e. same
diff --git a/src/proto_alpha/lib_protocol/test/double_endorsement.ml b/src/proto_alpha/lib_protocol/test/double_endorsement.ml
index 2b28e07bd..ae5534e36 100644
--- a/src/proto_alpha/lib_protocol/test/double_endorsement.ml
+++ b/src/proto_alpha/lib_protocol/test/double_endorsement.ml
@@ -30,14 +30,8 @@ let get_first_different_bakers ctxt =
 
 let get_first_different_endorsers ctxt =
   Context.get_endorsers ctxt >>=? fun endorsers ->
-  let endorsers = List.combine endorsers (0--((List.length endorsers) - 1)) in
-  let endorser_1 = List.hd endorsers in
-  let endorser_2 =
-    List.find (fun (endorser, _slot) ->
-        Signature.Public_key_hash.(<>)
-          (fst endorser_1) endorser)
-      (List.tl endorsers)
-  in
+  let endorser_1 = (List.hd endorsers) in
+  let endorser_2 = (List.hd (List.tl endorsers)) in
   return (endorser_1, endorser_2)
 
 let block_fork b =
@@ -59,8 +53,8 @@ let valid_double_endorsement_evidence () =
   block_fork b >>=? fun (blk_a, blk_b) ->
 
   Context.get_endorser (B blk_a) 0 >>=? fun delegate ->
-  Op.endorsement ~delegate (B blk_a) 0 >>=? fun endorsement_a ->
-  Op.endorsement ~delegate (B blk_b) 0 >>=? fun endorsement_b ->
+  Op.endorsement ~delegate (B blk_a) [0] >>=? fun endorsement_a ->
+  Op.endorsement ~delegate (B blk_b) [0] >>=? fun endorsement_b ->
   Block.bake ~operations:[endorsement_a] blk_a >>=? fun blk_a ->
   (* Block.bake ~operations:[endorsement_b] blk_b >>=? fun _ -> *)
 
@@ -89,7 +83,7 @@ let invalid_double_endorsement () =
   Context.init 10 >>=? fun (b, _) ->
   Block.bake b >>=? fun b ->
 
-  Op.endorsement (B b) 0 >>=? fun endorsement ->
+  Op.endorsement (B b) [0] >>=? fun endorsement ->
   Block.bake ~operation:endorsement b >>=? fun b ->
 
   Op.double_endorsement (B b) endorsement endorsement >>=? fun operation ->
@@ -105,8 +99,8 @@ let too_early_double_endorsement_evidence () =
   block_fork b >>=? fun (blk_a, blk_b) ->
 
   Context.get_endorser (B blk_a) 0 >>=? fun delegate ->
-  Op.endorsement ~delegate (B blk_a) 0 >>=? fun endorsement_a ->
-  Op.endorsement ~delegate (B blk_b) 0 >>=? fun endorsement_b ->
+  Op.endorsement ~delegate (B blk_a) [0] >>=? fun endorsement_a ->
+  Op.endorsement ~delegate (B blk_b) [0] >>=? fun endorsement_b ->
 
   Op.double_endorsement (B b) endorsement_a endorsement_b >>=? fun operation ->
   Block.bake ~operation b >>= fun res ->
@@ -124,8 +118,8 @@ let too_late_double_endorsement_evidence () =
   block_fork b >>=? fun (blk_a, blk_b) ->
 
   Context.get_endorser (B blk_a) 0 >>=? fun delegate ->
-  Op.endorsement ~delegate (B blk_a) 0 >>=? fun endorsement_a ->
-  Op.endorsement ~delegate (B blk_b) 0 >>=? fun endorsement_b ->
+  Op.endorsement ~delegate (B blk_a) [0] >>=? fun endorsement_a ->
+  Op.endorsement ~delegate (B blk_b) [0] >>=? fun endorsement_b ->
 
   fold_left_s (fun blk _ -> Block.bake_until_cycle_end blk)
     blk_a (1 -- (preserved_cycles + 1)) >>=? fun blk ->
@@ -143,10 +137,10 @@ let different_delegates () =
 
   block_fork b >>=? fun (blk_a, blk_b) ->
   get_first_different_endorsers (B blk_a)
-  >>=? fun ((endorser_a, slot_a), (endorser_b, slot_b)) ->
+  >>=? fun (endorser_a, endorser_b) ->
 
-  Op.endorsement ~delegate:endorser_a (B blk_a) slot_a >>=? fun e_a ->
-  Op.endorsement ~delegate:endorser_b (B blk_b) slot_b >>=? fun e_b ->
+  Op.endorsement ~delegate:endorser_a.delegate (B blk_a) endorser_a.slots >>=? fun e_a ->
+  Op.endorsement ~delegate:endorser_b.delegate (B blk_b) endorser_b.slots >>=? fun e_b ->
   Op.double_endorsement (B blk_a) e_a e_b >>=? fun operation ->
   Block.bake ~operation blk_a >>= fun res ->
   Assert.proto_error ~loc:__LOC__ res begin function
@@ -160,10 +154,10 @@ let wrong_delegate () =
 
   block_fork b >>=? fun (blk_a, blk_b) ->
   get_first_different_endorsers (B blk_a)
-  >>=? fun ((_endorser_a, slot_a), (endorser_b, slot_b)) ->
+  >>=? fun (endorser_a, endorser_b) ->
 
-  Op.endorsement ~delegate:endorser_b (B blk_a) slot_a >>=? fun endorsement_a ->
-  Op.endorsement ~delegate:endorser_b (B blk_b) slot_b >>=? fun endorsement_b ->
+  Op.endorsement ~delegate:endorser_b.delegate (B blk_a) endorser_a.slots >>=? fun endorsement_a ->
+  Op.endorsement ~delegate:endorser_b.delegate (B blk_b) endorser_b.slots >>=? fun endorsement_b ->
 
   Op.double_endorsement (B blk_a) endorsement_a endorsement_b >>=? fun operation ->
   Block.bake ~operation blk_a >>= fun e ->
diff --git a/src/proto_alpha/lib_protocol/test/endorsement.ml b/src/proto_alpha/lib_protocol/test/endorsement.ml
index b8aea78e1..42bfb2934 100644
--- a/src/proto_alpha/lib_protocol/test/endorsement.ml
+++ b/src/proto_alpha/lib_protocol/test/endorsement.ml
@@ -61,16 +61,17 @@ let assert_endorser_balance_consistency ~loc ?(priority=0) ?(nb_baking=0) ~nb_en
 (** Apply a single endorsement from the slot 0 endorser *)
 let simple_endorsement () =
   Context.init 5 >>=? fun (b, _) ->
-  let slot = 0 in
-  Incremental.begin_construction b >>=? fun inc ->
-
+  let slot = 1 in
   Context.get_endorser (B b) slot >>=? fun endorser ->
-  Op.endorsement ~delegate:endorser (I inc) slot >>=? fun op ->
-  Incremental.add_operation inc op >>=? fun inc ->
-
-  Context.Contract.balance (B b) (Contract.implicit_contract endorser) >>=? fun initial_balance ->
+  Op.endorsement ~delegate:endorser (B b) [slot] >>=? fun op ->
+  Context.Contract.balance (B b)
+    (Contract.implicit_contract endorser) >>=? fun initial_balance ->
+  Block.bake
+    ~policy:(Excluding [endorser])
+    ~operations:[op]
+    b >>=? fun b2 ->
   assert_endorser_balance_consistency ~loc:__LOC__
-    (I inc) ~nb_endorsement:1 endorser initial_balance
+    (B b2) ~nb_endorsement:1 endorser initial_balance
 
 (** Apply a maximum number of endorsement. A endorser can be selected
     twice. *)
@@ -80,29 +81,25 @@ let max_endorsement () =
 
   Context.get_endorsers (B b) >>=? fun endorsers ->
   Assert.equal_int ~loc:__LOC__
-    (List.length endorsers) endorsers_per_block >>=? fun () ->
+    (List.length (List.concat (List.map (fun { Alpha_services.Delegate.Endorsing_rights.slots } -> slots) endorsers))) endorsers_per_block >>=? fun () ->
 
-  fold_left_s (fun (ops, balances) (delegate, slot) ->
+  fold_left_s (fun (delegates, ops, balances) (endorser : Alpha_services.Delegate.Endorsing_rights.t) ->
+      let delegate = endorser.delegate in
       Context.Contract.balance (B b) (Contract.implicit_contract delegate) >>=? fun balance ->
-      Op.endorsement ~delegate (B b) slot >>=? fun op ->
-      return (op :: ops, balance :: balances)
+      Op.endorsement ~delegate (B b) endorser.slots >>=? fun op ->
+      return (delegate :: delegates, op :: ops, (List.length endorser.slots, balance) :: balances)
     )
-    ([], [])
-    (List.combine endorsers (0--(endorsers_per_block - 1))) >>=? fun (ops, previous_balances) ->
+    ([], [], [])
+    endorsers >>=? fun (delegates, ops, previous_balances) ->
 
-  Block.bake ~policy:(Excluding endorsers) ~operations:(List.rev ops) b >>=? fun b ->
-
-  let count acc =
-    List.find_all ((=) acc) endorsers |> List.length
-  in
+  Block.bake ~policy:(Excluding delegates) ~operations:(List.rev ops) b >>=? fun b ->
 
   (* One account can endorse more than one time per level, we must
      check that the bonds are summed up *)
-  iter_s (fun (endorser_account, previous_balance) ->
-      let nb_endorsement = count endorser_account in
+  iter_s (fun (endorser_account, (nb_endorsement, previous_balance)) ->
       assert_endorser_balance_consistency ~loc:__LOC__
         (B b) ~nb_endorsement endorser_account previous_balance
-    ) (List.combine endorsers (List.rev previous_balances))
+    ) (List.combine delegates previous_balances)
 
 (** Check that an endorser balance is consistent with a different piority *)
 let consistent_priority () =
@@ -118,7 +115,7 @@ let consistent_priority () =
   in
   Context.Contract.balance (B b) (Contract.implicit_contract endorser) >>=? fun balance ->
 
-  Op.endorsement ~delegate:endorser (B b) slot >>=? fun operation ->
+  Op.endorsement ~delegate:endorser (B b) [slot] >>=? fun operation ->
   Block.bake ~policy:( Excluding [ endorser ] ) ~operation b >>=? fun b ->
 
   assert_endorser_balance_consistency ~loc:__LOC__ ~priority:15
@@ -142,7 +139,7 @@ let consistent_priorities () =
       in
 
       Context.Contract.balance (B b) (Contract.implicit_contract endorser) >>=? fun balance ->
-      Op.endorsement ~delegate:endorser (B b) slot >>=? fun operation ->
+      Op.endorsement ~delegate:endorser (B b) [slot] >>=? fun operation ->
       Block.bake ~policy:( Excluding [ endorser ] ) ~operation b >>=? fun b ->
 
       assert_endorser_balance_consistency ~loc:__LOC__ ~priority
@@ -158,7 +155,7 @@ let reward_retrieval () =
   let slot = 0 in
   Context.get_endorser (B b) slot >>=? fun endorser ->
   Context.Contract.balance (B b) (Contract.implicit_contract endorser) >>=? fun balance ->
-  Op.endorsement ~delegate:endorser (B b) slot >>=? fun operation ->
+  Op.endorsement ~delegate:endorser (B b) [slot] >>=? fun operation ->
   Block.bake ~policy:(Excluding [ endorser ]) ~operation b >>=? fun b ->
   (* Bake (preserved_cycles + 1) cycles *)
   fold_left_s (fun b _ ->
@@ -178,7 +175,7 @@ let wrong_endorsement_predecessor () =
 
   Context.get_endorser (B b) 0 >>=? fun genesis_endorser ->
   Block.bake b >>=? fun b' ->
-  Op.endorsement ~delegate:genesis_endorser ~signing_context:(B b') (B b) 0  >>=? fun operation ->
+  Op.endorsement ~delegate:genesis_endorser ~signing_context:(B b') (B b) [0]  >>=? fun operation ->
   Block.bake ~operation b' >>= fun res ->
 
   Assert.proto_error ~loc:__LOC__ res begin function
@@ -192,7 +189,7 @@ let invalid_endorsement_level () =
   Context.init 5 >>=? fun (b, _) ->
   Context.get_level (B b) >>=? fun genesis_level ->
   Block.bake b >>=? fun b ->
-  Op.endorsement ~level:genesis_level (B b) 0  >>=? fun operation ->
+  Op.endorsement ~level:genesis_level (B b) [0] >>=? fun operation ->
   Block.bake ~operation b >>= fun res ->
 
   Assert.proto_error ~loc:__LOC__ res begin function
@@ -204,9 +201,9 @@ let invalid_endorsement_level () =
 let duplicate_endorsement () =
   Context.init 5 >>=? fun (b, _) ->
   Incremental.begin_construction b >>=? fun inc ->
-  Op.endorsement (B b) 0  >>=? fun operation ->
+  Op.endorsement (B b) [0]  >>=? fun operation ->
   Incremental.add_operation inc operation >>=? fun inc ->
-  Op.endorsement (B b) 0  >>=? fun operation ->
+  Op.endorsement (B b) [0]  >>=? fun operation ->
   Incremental.add_operation inc operation >>= fun res ->
 
   Assert.proto_error ~loc:__LOC__ res begin function
@@ -219,8 +216,8 @@ let invalid_endorsement_slot () =
   Context.init 64 >>=? fun (b, _) ->
   Context.get_constants (B b) >>=? fun Constants.
     { parametric = { endorsers_per_block ; _ } ; _  } ->
-
-  Op.endorsement (B b) (endorsers_per_block + 1)  >>=? fun operation ->
+  Context.get_endorser (B b) 0 >>=? fun endorser ->
+  Op.endorsement ~delegate:endorser (B b) [endorsers_per_block + 1]  >>=? fun operation ->
 
   Block.bake ~operation b >>= fun res ->
 
diff --git a/src/proto_alpha/lib_protocol/test/helpers/block.ml b/src/proto_alpha/lib_protocol/test/helpers/block.ml
index 1bcdb6354..de083142b 100644
--- a/src/proto_alpha/lib_protocol/test/helpers/block.ml
+++ b/src/proto_alpha/lib_protocol/test/helpers/block.ml
@@ -43,26 +43,31 @@ type baker_policy =
   | Excluding of public_key_hash list
 
 let get_next_baker_by_priority priority block =
-  Alpha_services.Delegate.Baker.rights rpc_ctxt
-    ~max_priority:(priority+1) block >>=? fun (_, bakers) ->
-  let pkh, timestamp = List.nth bakers priority in
-  return (pkh, priority, timestamp)
+  Alpha_services.Delegate.Baking_rights.get rpc_ctxt
+    ~all:true
+    ~max_priority:(priority+1) block >>=? fun bakers ->
+  let { Alpha_services.Delegate.Baking_rights.delegate = pkh ;
+        timestamp} = List.find (fun { Alpha_services.Delegate.Baking_rights.priority = p } -> p = priority)  bakers in
+  return (pkh, priority, Option.unopt_exn (Failure "") timestamp)
 
 let get_next_baker_by_account pkh block =
-  Alpha_services.Delegate.Baker.rights rpc_ctxt
-    ~max_priority:30 block >>=? fun (_, bakers) ->
-  let ((_pkh, timestamp), priority) =  Test_utils.findi
-      (fun (pkh', _) -> Signature.Public_key_hash.equal pkh pkh')
-      bakers in
-  return (pkh, priority, timestamp)
+  Alpha_services.Delegate.Baking_rights.get rpc_ctxt
+    ~delegates:[pkh]
+    ~max_priority:256 block >>=? fun bakers ->
+  let { Alpha_services.Delegate.Baking_rights.delegate = pkh ;
+        timestamp ; priority } = List.hd bakers in
+  return (pkh, priority, Option.unopt_exn (Failure "") timestamp)
 
 let get_next_baker_excluding excludes block =
-  Alpha_services.Delegate.Baker.rights rpc_ctxt
-    ~max_priority:((List.length excludes)+10) block >>=? fun (_, bakers) ->
-  let (pkh,timestamp),priority = Test_utils.findi
-      (fun (pkh, _) -> not (List.mem pkh excludes))
+  Alpha_services.Delegate.Baking_rights.get rpc_ctxt
+    ~max_priority:256 block >>=? fun bakers ->
+  let { Alpha_services.Delegate.Baking_rights.delegate = pkh ;
+        timestamp ; priority } =
+    List.find
+      (fun { Alpha_services.Delegate.Baking_rights.delegate } ->
+         not (List.mem delegate excludes))
       bakers in
-  return (pkh, priority, timestamp)
+  return (pkh, priority, Option.unopt_exn (Failure "") timestamp)
 
 let dispatch_policy = function
   | By_priority p -> get_next_baker_by_priority p
@@ -112,9 +117,14 @@ module Forge = struct
     (* Finds the baker that should sign from the header *)
     let baker_of_a_block header =
       let priority = header.contents.priority in
-      Alpha_services.Delegate.Baker.rights rpc_ctxt
-        ~max_priority:(priority+1) pred >>=? fun (_, bakers) ->
-      let pkh, _ = List.nth bakers priority in
+      Alpha_services.Delegate.Baking_rights.get rpc_ctxt
+        ~all:true
+        ~max_priority:(priority+1)
+        pred >>=? fun bakers ->
+      let { Alpha_services.Delegate.Baking_rights.delegate = pkh } =
+        List.find
+          (fun { Alpha_services.Delegate.Baking_rights.priority = p } -> p = priority)
+          bakers in
       Account.find pkh
     in
     baker_of_a_block { shell ; contents } >>=? fun delegate ->
diff --git a/src/proto_alpha/lib_protocol/test/helpers/context.ml b/src/proto_alpha/lib_protocol/test/helpers/context.ml
index 80cf51f74..2d9d3816d 100644
--- a/src/proto_alpha/lib_protocol/test/helpers/context.ml
+++ b/src/proto_alpha/lib_protocol/test/helpers/context.ml
@@ -64,21 +64,23 @@ let rpc_ctxt = object
 end
 
 let get_endorsers ctxt =
-  Alpha_services.Delegate.Endorser.rights
-    rpc_ctxt ctxt >>=? fun (_level, endorsers) ->
-  return endorsers
+  Alpha_services.Delegate.Endorsing_rights.get rpc_ctxt ctxt
 
 let get_endorser ctxt slot =
-  Alpha_services.Delegate.Endorser.rights
-    ~max_priority:(slot+1) rpc_ctxt ctxt >>=? fun (_level, endorsers) ->
-  try return (List.nth endorsers slot)
+  Alpha_services.Delegate.Endorsing_rights.get
+    rpc_ctxt ctxt >>=? fun endorsers ->
+  try return (List.find (fun {Alpha_services.Delegate.Endorsing_rights.slots} -> List.mem slot slots) endorsers).delegate
   with _ ->
     failwith "Failed to lookup endorsers for ctxt %a, slot %d."
       Block_hash.pp_short (branch ctxt) slot
 
 let get_bakers ctxt =
-  Alpha_services.Delegate.Baker.rights rpc_ctxt ~max_priority:30 ctxt >>=? fun (_, bakers) ->
-  return (List.map fst bakers)
+  Alpha_services.Delegate.Baking_rights.get
+    ~max_priority:256
+    rpc_ctxt ctxt >>=? fun bakers ->
+  return (List.map
+            (fun p -> p.Alpha_services.Delegate.Baking_rights.delegate)
+            bakers)
 
 let get_constants b =
   Alpha_services.Constants.all rpc_ctxt b
diff --git a/src/proto_alpha/lib_protocol/test/helpers/context.mli b/src/proto_alpha/lib_protocol/test/helpers/context.mli
index 88776aae7..a93174f6a 100644
--- a/src/proto_alpha/lib_protocol/test/helpers/context.mli
+++ b/src/proto_alpha/lib_protocol/test/helpers/context.mli
@@ -18,7 +18,7 @@ val branch: t -> Block_hash.t
 
 val get_level: t -> Raw_level.t tzresult Lwt.t
 
-val get_endorsers: t -> public_key_hash list tzresult Lwt.t
+val get_endorsers: t -> Alpha_services.Delegate.Endorsing_rights.t list tzresult Lwt.t
 
 val get_endorser: t -> int -> public_key_hash tzresult Lwt.t
 
diff --git a/src/proto_alpha/lib_protocol/test/helpers/op.ml b/src/proto_alpha/lib_protocol/test/helpers/op.ml
index 9219eb1cb..24e0b2da6 100644
--- a/src/proto_alpha/lib_protocol/test/helpers/op.ml
+++ b/src/proto_alpha/lib_protocol/test/helpers/op.ml
@@ -25,10 +25,10 @@ let sign ?(watermark = Signature.Generic_operation) sk ctxt contents =
   }
 
 let endorsement ?delegate ?level ctxt =
-  fun ?(signing_context=ctxt) slot ->
+  fun ?(signing_context=ctxt) slots ->
     begin
       match delegate with
-      | None -> Context.get_endorser ctxt slot
+      | None -> Context.get_endorser ctxt (List.hd slots)
       | Some delegate -> return delegate
     end >>=? fun delegate_pkh ->
     Account.find delegate_pkh >>=? fun delegate ->
@@ -38,7 +38,7 @@ let endorsement ?delegate ?level ctxt =
       | Some level -> return level
     end >>=? fun level ->
     let op =
-      let operations = Endorsements { block = Context.branch ctxt ; level ; slots = [slot] } in
+      let operations = Endorsements { block = Context.branch ctxt ; level ; slots = slots } in
       Sourced_operation (Consensus_operation operations) in
     return (sign ~watermark:Signature.Endorsement delegate.sk signing_context op)
 
@@ -107,7 +107,7 @@ let miss_signed_endorsement ?level ctxt slot =
   end >>=? fun level ->
   Context.get_endorser ctxt slot >>=? fun real_delegate_pkh ->
   let delegate = Account.find_alternate real_delegate_pkh in
-  endorsement ~delegate:delegate.pkh ~level ctxt slot
+  endorsement ~delegate:delegate.pkh ~level ctxt [slot]
 
 let transaction ?fee ?gas_limit ?storage_limit ?parameters ctxt
     (src:Contract.t) (dst:Contract.t)
diff --git a/src/proto_alpha/lib_protocol/test/helpers/op.mli b/src/proto_alpha/lib_protocol/test/helpers/op.mli
index a16450556..798093d8d 100644
--- a/src/proto_alpha/lib_protocol/test/helpers/op.mli
+++ b/src/proto_alpha/lib_protocol/test/helpers/op.mli
@@ -14,7 +14,7 @@ val endorsement:
   ?delegate:public_key_hash ->
   ?level:Raw_level.t ->
   Context.t -> ?signing_context:Context.t ->
-  int -> Operation.t tzresult Lwt.t
+  int list -> Operation.t tzresult Lwt.t
 
 val miss_signed_endorsement:
   ?level:Raw_level.t ->