diff --git a/src/lib_protocol_environment/dummy_context.ml b/src/lib_protocol_environment/dummy_context.ml
index 57148b40d96b1cc04eaeb58c5dc490b41aba08ae..50d175e2ad86139585a1c376daf2a0d7e0154c50 100644
--- a/src/lib_protocol_environment/dummy_context.ml
+++ b/src/lib_protocol_environment/dummy_context.ml
@@ -28,7 +28,7 @@ module M = struct
 
   type key = string list
 
-  type value = Bytes.t
+  type value = string
 
   type tree = |
 
diff --git a/src/lib_protocol_environment/environment_V0.ml b/src/lib_protocol_environment/environment_V0.ml
index 7e0e0314682363b43a21dcee4b52cab640e10194..49d683c03468cf855fa4e231da7c7067697c6133 100644
--- a/src/lib_protocol_environment/environment_V0.ml
+++ b/src/lib_protocol_environment/environment_V0.ml
@@ -866,9 +866,11 @@ struct
   module Context = struct
     include Context
 
-    let set = add
+    type value = bytes
 
-    let get = find
+    let set t k v = add t k (Bytes.unsafe_to_string v)
+
+    let get t k = find t k >|= Option.map ~f:Bytes.unsafe_of_string
 
     let dir_mem = mem_tree
 
diff --git a/src/lib_protocol_environment/environment_V1.ml b/src/lib_protocol_environment/environment_V1.ml
index 10eada363cd7f29317b7be95ab20188f5643bf76..aa40fea03f8b2de38dbc7d8fe7d6e21e653f1517 100644
--- a/src/lib_protocol_environment/environment_V1.ml
+++ b/src/lib_protocol_environment/environment_V1.ml
@@ -1053,9 +1053,11 @@ struct
   module Context = struct
     include Context
 
-    let set = add
+    type value = bytes
 
-    let get = find
+    let set t k v = add t k (Bytes.unsafe_to_string v)
+
+    let get t k = find t k >|= Option.map Bytes.unsafe_of_string
 
     let dir_mem = mem_tree
 
diff --git a/src/lib_protocol_environment/environment_context.ml b/src/lib_protocol_environment/environment_context.ml
index 21323951a5673d74faa9a02a654b73818e551e7d..304bc13ba7d6f30c0d7f9a3a78b4ee097ecd3a00 100644
--- a/src/lib_protocol_environment/environment_context.ml
+++ b/src/lib_protocol_environment/environment_context.ml
@@ -74,7 +74,7 @@ end
 module Context = struct
   type key = string list
 
-  type value = Bytes.t
+  type value = string
 
   type ('ctxt, 'tree) ops =
     (module CONTEXT with type t = 'ctxt and type tree = 'tree)
diff --git a/src/lib_protocol_environment/environment_context_intf.ml b/src/lib_protocol_environment/environment_context_intf.ml
index 2a1a7e89386f8fc517ec2dd6da95d6ebdf155b09..bf31de16ba09023d0041545d00e9b7b23c0e6435 100644
--- a/src/lib_protocol_environment/environment_context_intf.ml
+++ b/src/lib_protocol_environment/environment_context_intf.ml
@@ -35,7 +35,7 @@ module type TREE = sig
 end
 
 module type S = sig
-  include VIEW with type key = string list and type value = bytes
+  include VIEW with type key = string list and type value = string
 
   module Tree :
     TREE
diff --git a/src/lib_protocol_environment/proxy_context.ml b/src/lib_protocol_environment/proxy_context.ml
index b0c509514c93c835ed8a21c11c04a6b0769eeba9..691f24ca8e7083551dc39e2cd90d1408cd8177a2 100644
--- a/src/lib_protocol_environment/proxy_context.ml
+++ b/src/lib_protocol_environment/proxy_context.ml
@@ -30,7 +30,7 @@ module M = struct
 
   type value = Local.value
 
-  type tree = [`Value of bytes | `Tree of tree TzString.Map.t]
+  type tree = [`Value of value | `Tree of tree TzString.Map.t]
 
   module type ProxyDelegate = sig
     val proxy_dir_mem : key -> bool tzresult Lwt.t
diff --git a/src/lib_protocol_environment/proxy_context.mli b/src/lib_protocol_environment/proxy_context.mli
index 7ad4f8c7622a74a9159c034884d3d77f6775f3ee..4a815c497a2b635a38f412c67d81c796ae22a318 100644
--- a/src/lib_protocol_environment/proxy_context.mli
+++ b/src/lib_protocol_environment/proxy_context.mli
@@ -40,9 +40,9 @@ open Tezos_protocol_environment
 module M : sig
   type key = string list (* as in environment_context.mli *)
 
-  type value = Bytes.t (* as in environment_context.mli *)
+  type value = string (* as in environment_context.mli *)
 
-  type tree = [`Value of bytes | `Tree of tree TzString.Map.t]
+  type tree = [`Value of value | `Tree of tree TzString.Map.t]
 
   module type ProxyDelegate = sig
     (** Whether [mem] would return Some Dir _ *)
diff --git a/src/lib_protocol_environment/sigs/v2/context.mli b/src/lib_protocol_environment/sigs/v2/context.mli
index 7e521fdef38cf50dc8b5ffd3a1d9fa80a0d9f49d..65324ae30d67ae071a75f7612c692776d2991a3d 100644
--- a/src/lib_protocol_environment/sigs/v2/context.mli
+++ b/src/lib_protocol_environment/sigs/v2/context.mli
@@ -127,6 +127,8 @@ module type TREE = sig
   (** The type for context trees. *)
   type tree
 
+  include VIEW with type t := tree and type tree := tree
+
   (** [empty _] is the empty tree. *)
   val empty : t -> tree
 
@@ -135,7 +137,7 @@ module type TREE = sig
 
   (** [kind t] is [t]'s kind. It's either a tree node or a leaf
       value. *)
-  val kind : tree -> [`Value of bytes | `Tree]
+  val kind : tree -> [`Value of value | `Tree]
 
   (** [hash t] is [t]'s Merkle hash. *)
   val hash : tree -> Context_hash.t
@@ -143,8 +145,6 @@ module type TREE = sig
   (** [equal x y] is true iff [x] and [y] have the same Merkle hash. *)
   val equal : tree -> tree -> bool
 
-  include VIEW with type t := tree and type tree := tree
-
   (** {2 Caches} *)
 
   (** [clear ?depth t] clears all caches in the tree [t] for subtrees with a
@@ -153,7 +153,7 @@ module type TREE = sig
   val clear : ?depth:int -> tree -> unit
 end
 
-include VIEW with type key = string list and type value = bytes
+include VIEW with type key = string list and type value = string
 
 module Tree :
   TREE
diff --git a/src/lib_protocol_environment/test/test_mem_context.ml b/src/lib_protocol_environment/test/test_mem_context.ml
index eb6064d333000853b537b57451a8c54b5e7a4d28..0d7549358d338adc1cc5fbbdea93eb80d0684c04 100644
--- a/src/lib_protocol_environment/test/test_mem_context.ml
+++ b/src/lib_protocol_environment/test/test_mem_context.ml
@@ -40,24 +40,18 @@
 *)
 
 let create_block2 ctxt =
-  Context.add ctxt ["a"; "b"] (Bytes.of_string "Novembre")
+  Context.add ctxt ["a"; "b"] "Novembre"
   >>= fun ctxt ->
-  Context.add ctxt ["a"; "c"] (Bytes.of_string "Juin")
-  >>= fun ctxt ->
-  Context.add ctxt ["version"] (Bytes.of_string "0.0")
-  >>= fun ctxt -> Lwt.return ctxt
+  Context.add ctxt ["a"; "c"] "Juin"
+  >>= fun ctxt -> Context.add ctxt ["version"] "0.0"
 
 let create_block3a ctxt =
   Context.remove ctxt ["a"; "b"]
-  >>= fun ctxt ->
-  Context.add ctxt ["a"; "d"] (Bytes.of_string "Mars")
-  >>= fun ctxt -> Lwt.return ctxt
+  >>= fun ctxt -> Context.add ctxt ["a"; "d"] "Mars"
 
 let create_block3b ctxt =
   Context.remove ctxt ["a"; "c"]
-  >>= fun ctxt ->
-  Context.add ctxt ["a"; "d"] (Bytes.of_string "Février")
-  >>= fun ctxt -> Lwt.return ctxt
+  >>= fun ctxt -> Context.add ctxt ["a"; "d"] "Février"
 
 type t = {
   genesis : Context.t;
@@ -78,8 +72,6 @@ let wrap_context_init f _ () =
 
 (** Simple test *)
 
-let c = function None -> None | Some s -> Some (Bytes.to_string s)
-
 (** Restore the context applied until [block2]. It is asserted that
     the following key-values are present:
     - (["version"], ["0.0"])
@@ -89,13 +81,13 @@ let c = function None -> None | Some s -> Some (Bytes.to_string s)
 let test_simple {block2 = ctxt; _} =
   Context.find ctxt ["version"]
   >>= fun version ->
-  Assert.equal_string_option ~msg:__LOC__ (c version) (Some "0.0") ;
+  Assert.equal_string_option ~msg:__LOC__ version (Some "0.0") ;
   Context.find ctxt ["a"; "b"]
   >>= fun novembre ->
-  Assert.equal_string_option (Some "Novembre") (c novembre) ;
+  Assert.equal_string_option (Some "Novembre") novembre ;
   Context.find ctxt ["a"; "c"]
   >>= fun juin ->
-  Assert.equal_string_option ~msg:__LOC__ (Some "Juin") (c juin) ;
+  Assert.equal_string_option ~msg:__LOC__ (Some "Juin") juin ;
   Lwt.return_unit
 
 (** Restore the context applied until [block3a]. It is asserted that
@@ -109,16 +101,16 @@ let test_simple {block2 = ctxt; _} =
 let test_continuation {block3a = ctxt; _} =
   Context.find ctxt ["version"]
   >>= fun version ->
-  Assert.equal_string_option ~msg:__LOC__ (Some "0.0") (c version) ;
+  Assert.equal_string_option ~msg:__LOC__ (Some "0.0") version ;
   Context.find ctxt ["a"; "b"]
   >>= fun novembre ->
-  Assert.is_none ~msg:__LOC__ (c novembre) ;
+  Assert.is_none ~msg:__LOC__ novembre ;
   Context.find ctxt ["a"; "c"]
   >>= fun juin ->
-  Assert.equal_string_option ~msg:__LOC__ (Some "Juin") (c juin) ;
+  Assert.equal_string_option ~msg:__LOC__ (Some "Juin") juin ;
   Context.find ctxt ["a"; "d"]
   >>= fun mars ->
-  Assert.equal_string_option ~msg:__LOC__ (Some "Mars") (c mars) ;
+  Assert.equal_string_option ~msg:__LOC__ (Some "Mars") mars ;
   Lwt.return_unit
 
 (** Restore the context applied until [block3b]. It is asserted that
@@ -132,49 +124,49 @@ let test_continuation {block3a = ctxt; _} =
 let test_fork {block3b = ctxt; _} =
   Context.find ctxt ["version"]
   >>= fun version ->
-  Assert.equal_string_option ~msg:__LOC__ (Some "0.0") (c version) ;
+  Assert.equal_string_option ~msg:__LOC__ (Some "0.0") version ;
   Context.find ctxt ["a"; "b"]
   >>= fun novembre ->
-  Assert.equal_string_option ~msg:__LOC__ (Some "Novembre") (c novembre) ;
+  Assert.equal_string_option ~msg:__LOC__ (Some "Novembre") novembre ;
   Context.find ctxt ["a"; "c"]
   >>= fun juin ->
-  Assert.is_none ~msg:__LOC__ (c juin) ;
+  Assert.is_none ~msg:__LOC__ juin ;
   Context.find ctxt ["a"; "d"]
   >>= fun mars ->
-  Assert.equal_string_option ~msg:__LOC__ (Some "Février") (c mars) ;
+  Assert.equal_string_option ~msg:__LOC__ (Some "Février") mars ;
   Lwt.return_unit
 
 (** Restore the context at [genesis] and explicitly replay
     setting/getting key-values.
 *)
 let test_replay {genesis = ctxt0; _} =
-  Context.add ctxt0 ["version"] (Bytes.of_string "0.0")
+  Context.add ctxt0 ["version"] "0.0"
   >>= fun ctxt1 ->
-  Context.add ctxt1 ["a"; "b"] (Bytes.of_string "Novembre")
+  Context.add ctxt1 ["a"; "b"] "Novembre"
   >>= fun ctxt2 ->
-  Context.add ctxt2 ["a"; "c"] (Bytes.of_string "Juin")
+  Context.add ctxt2 ["a"; "c"] "Juin"
   >>= fun ctxt3 ->
-  Context.add ctxt3 ["a"; "d"] (Bytes.of_string "July")
+  Context.add ctxt3 ["a"; "d"] "July"
   >>= fun ctxt4a ->
-  Context.add ctxt3 ["a"; "d"] (Bytes.of_string "Juillet")
+  Context.add ctxt3 ["a"; "d"] "Juillet"
   >>= fun ctxt4b ->
-  Context.add ctxt4a ["a"; "b"] (Bytes.of_string "November")
+  Context.add ctxt4a ["a"; "b"] "November"
   >>= fun ctxt5a ->
   Context.find ctxt4a ["a"; "b"]
   >>= fun novembre ->
-  Assert.equal_string_option ~msg:__LOC__ (Some "Novembre") (c novembre) ;
+  Assert.equal_string_option ~msg:__LOC__ (Some "Novembre") novembre ;
   Context.find ctxt5a ["a"; "b"]
   >>= fun november ->
-  Assert.equal_string_option ~msg:__LOC__ (Some "November") (c november) ;
+  Assert.equal_string_option ~msg:__LOC__ (Some "November") november ;
   Context.find ctxt5a ["a"; "d"]
   >>= fun july ->
-  Assert.equal_string_option ~msg:__LOC__ (Some "July") (c july) ;
+  Assert.equal_string_option ~msg:__LOC__ (Some "July") july ;
   Context.find ctxt4b ["a"; "b"]
   >>= fun novembre ->
-  Assert.equal_string_option ~msg:__LOC__ (Some "Novembre") (c novembre) ;
+  Assert.equal_string_option ~msg:__LOC__ (Some "Novembre") novembre ;
   Context.find ctxt4b ["a"; "d"]
   >>= fun juillet ->
-  Assert.equal_string_option ~msg:__LOC__ (Some "Juillet") (c juillet) ;
+  Assert.equal_string_option ~msg:__LOC__ (Some "Juillet") juillet ;
   Lwt.return_unit
 
 let fold_keys s root ~init ~f =
@@ -191,15 +183,15 @@ let keys t = fold_keys t ~init:[] ~f:(fun k acc -> Lwt.return (k :: acc))
     of key prefixes using {!Context.fold}.
 *)
 let test_fold_keys {genesis = ctxt; _} =
-  Context.add ctxt ["a"; "b"] (Bytes.of_string "Novembre")
+  Context.add ctxt ["a"; "b"] "Novembre"
   >>= fun ctxt ->
-  Context.add ctxt ["a"; "c"] (Bytes.of_string "Juin")
+  Context.add ctxt ["a"; "c"] "Juin"
   >>= fun ctxt ->
-  Context.add ctxt ["a"; "d"; "e"] (Bytes.of_string "Septembre")
+  Context.add ctxt ["a"; "d"; "e"] "Septembre"
   >>= fun ctxt ->
-  Context.add ctxt ["f"] (Bytes.of_string "Avril")
+  Context.add ctxt ["f"] "Avril"
   >>= fun ctxt ->
-  Context.add ctxt ["g"; "h"] (Bytes.of_string "Avril")
+  Context.add ctxt ["g"; "h"] "Avril"
   >>= fun ctxt ->
   keys ctxt []
   >>= fun l ->
@@ -225,8 +217,8 @@ let test_fold_keys {genesis = ctxt; _} =
   Lwt.return_unit
 
 let test_fold {genesis = ctxt; _} =
-  let foo1 = Bytes.of_string "foo1" in
-  let foo2 = Bytes.of_string "foo2" in
+  let foo1 = "foo1" in
+  let foo2 = "foo2" in
   Context.add ctxt ["foo"; "toto"] foo1
   >>= fun ctxt ->
   Context.add ctxt ["foo"; "bar"; "toto"] foo2
@@ -288,7 +280,7 @@ let steps =
 [@@ocamlformat "disable"]
 
 let bindings =
-  let zero = Bytes.make 10 '0' in
+  let zero = Bytes.make 10 '0' |> Bytes.unsafe_to_string in
   List.map (fun x -> (["root"; x], zero)) steps
 
 let test_fold_order {genesis = ctxt; _} =
@@ -313,8 +305,8 @@ let test_trees {genesis = ctxt; _} =
       assert (List.length k = 1) ;
       Assert.fail_msg "empty")
   >>= fun () ->
-  let foo1 = Bytes.of_string "foo1" in
-  let foo2 = Bytes.of_string "foo2" in
+  let foo1 = "foo1" in
+  let foo2 = "foo2" in
   Context.Tree.empty ctxt
   |> fun v1 ->
   Context.Tree.add v1 ["foo"; "toto"] foo1
@@ -361,10 +353,10 @@ let test_trees {genesis = ctxt; _} =
   >>= fun v1 ->
   Context.Tree.find v1 ["foo"; "bar"; "toto"]
   >>= fun v ->
-  Assert.equal_bytes_option ~msg:__LOC__ None v ;
+  Assert.equal_string_option ~msg:__LOC__ None v ;
   Context.Tree.find v1 ["foo"; "toto"]
   >>= fun v ->
-  Assert.equal_bytes_option ~msg:__LOC__ (Some foo1) v ;
+  Assert.equal_string_option ~msg:__LOC__ (Some foo1) v ;
   Context.Tree.empty ctxt
   |> fun v1 ->
   Context.Tree.add v1 ["foo"; "1"] foo1
@@ -377,7 +369,7 @@ let test_trees {genesis = ctxt; _} =
   >>= fun v1 ->
   Context.Tree.find v1 ["foo"; "1"]
   >>= fun v ->
-  Assert.equal_bytes_option ~msg:__LOC__ None v ;
+  Assert.equal_string_option ~msg:__LOC__ None v ;
   Context.Tree.remove v1 []
   >>= fun v1 ->
   Assert.equal_bool ~msg:__LOC__ true (Context.Tree.is_empty v1) ;
@@ -431,7 +423,7 @@ let check_eq_domains d1 d2 =
   Assert.equal ~eq ~prn:PP.domain_to_string d1 d2
 
 let test_domain0 () =
-  let b0 = Bytes.of_string "0" in
+  let b0 = "0" in
   let k1 = ["a"] in
   let k2 = ["b"] in
   let k3 = ["c"] in
@@ -450,7 +442,7 @@ let test_domain0 () =
   Lwt.return_unit
 
 let test_domain1 () =
-  let b0 = Bytes.of_string "0" in
+  let b0 = "0" in
   let k1 = ["a"; "b"] in
   let k2 = ["a"; "c"; "d"] in
   let ctxt = Memory_context.empty in
@@ -466,7 +458,7 @@ let test_domain1 () =
   Lwt.return_unit
 
 let test_domain2 () =
-  let b0 = Bytes.of_string "0" in
+  let b0 = "0" in
   let k1 = ["a"; "b"] in
   let k2 = ["a"; "c"; "d"] in
   let k3 = ["a"; "c"; "e"] in
diff --git a/src/lib_protocol_environment/test/test_mem_context_array_theory.ml b/src/lib_protocol_environment/test/test_mem_context_array_theory.ml
index 9db7b8e2cc5b610ccf3db96f36e198330f08538e..60895c4c4c89712f4ed6b671898537e3ed2c099f 100644
--- a/src/lib_protocol_environment/test/test_mem_context_array_theory.ml
+++ b/src/lib_protocol_environment/test/test_mem_context_array_theory.ml
@@ -74,7 +74,7 @@ let key_gen mode =
 
 let value_gen =
   let open Crowbar in
-  map [bytes] Bytes.of_string
+  bytes
 
 let key_value_gen kmode =
   let open Crowbar in
@@ -163,7 +163,7 @@ let test_get_set (ctxt, (k, v)) =
       Crowbar.check_eq at_k v
 
 let value_opt ppf value_opt =
-  let ppv ppf v = Format.fprintf ppf "%s" @@ Bytes.to_string v in
+  let ppv ppf v = Format.fprintf ppf "%s" v in
   Format.pp_print_option ppv ppf value_opt
 
 (* Tests that: forall k2 <> k1, (get (set m k1 v) k2) equals get m k2;
diff --git a/src/lib_proxy/proxy_getter.ml b/src/lib_proxy/proxy_getter.ml
index 52a1d69d76b056888360ed7105ba655b733fc73b..dfb9434152593939fa367987f60e91e93d6adae3 100644
--- a/src/lib_proxy/proxy_getter.ml
+++ b/src/lib_proxy/proxy_getter.ml
@@ -65,8 +65,8 @@ let rec raw_context_to_tree
     (raw : Tezos_shell_services.Block_services.raw_context) :
     Proxy_context.M.tree option =
   match raw with
-  | Key (bytes : Bytes.t) ->
-      Some (`Value bytes)
+  | Key (v : string) ->
+      Some (`Value v)
   | Cut ->
       None
   | Dir pairs ->
diff --git a/src/lib_proxy/test/test_proxy.ml b/src/lib_proxy/test/test_proxy.ml
index 34b76cd0a3ec6ca65523d0838403ac94fc818450..016b991008b6f4c7b33586651b7a73b2a9460d4a 100644
--- a/src/lib_proxy/test/test_proxy.ml
+++ b/src/lib_proxy/test/test_proxy.ml
@@ -74,7 +74,7 @@ let mock_proto_rpc () =
       in
       let rec mock_tree = function
         | [] ->
-            `Value Bytes.empty
+            `Value ""
         | hd :: tail ->
             `Tree (StringMap.add hd (mock_tree tail) StringMap.empty)
       in
diff --git a/src/lib_shell/patch_context.ml b/src/lib_shell/patch_context.ml
index d4e9e5f580caa66e35147a00e74bbc1e9a4eb737..5ea17b35b08a09f990d3cd0bd376bfcf12e50a4e 100644
--- a/src/lib_shell/patch_context.ml
+++ b/src/lib_shell/patch_context.ml
@@ -29,10 +29,9 @@ let patch_context (genesis : Genesis.t) key_json ctxt =
   | None ->
       Lwt.return ctxt
   | Some (key, json) ->
-      Tezos_storage.Context.add
-        ctxt
-        [key]
-        (Data_encoding.Binary.to_bytes_exn Data_encoding.json json) )
+      let v = Data_encoding.Binary.to_bytes_exn Data_encoding.json json in
+      let v = Bytes.unsafe_to_string v in
+      Tezos_storage.Context.add ctxt [key] v )
   >>= fun ctxt ->
   Registered_protocol.get_result genesis.protocol
   >>=? fun proto ->
diff --git a/src/lib_shell_benchmarks/io_benchmarks.ml b/src/lib_shell_benchmarks/io_benchmarks.ml
index b9f07685842e8e82cfe7bb5fabded4ed5374d49c..7c4202b88e0ccdfd27fbc213d553181f6cfb62ec 100644
--- a/src/lib_shell_benchmarks/io_benchmarks.ml
+++ b/src/lib_shell_benchmarks/io_benchmarks.ml
@@ -359,8 +359,8 @@ module Context_size_dependent_write_bench : Benchmark.S = struct
           cfg.commit_batch_size
           keys
       in
-      let bytes = Base_samplers.uniform_bytes rng_state ~nbytes:value_size in
-      let context = write_storage context random_key bytes in
+      let str = Base_samplers.uniform_string rng_state ~nbytes:value_size in
+      let context = write_storage context random_key str in
       let finalizer () =
         Gc.compact () ;
         Lwt_main.run
@@ -772,10 +772,10 @@ module Irmin_pack_write_bench : Benchmark.S = struct
       let context =
         List.fold_left
           (fun context key ->
-            let bytes =
-              Base_samplers.uniform_bytes rng_state ~nbytes:value_size
+            let str =
+              Base_samplers.uniform_string rng_state ~nbytes:value_size
             in
-            write_storage context key bytes)
+            write_storage context key str)
           context
           keys_written_to
       in
@@ -1044,10 +1044,10 @@ module Write_random_keys_bench : Benchmark.S = struct
       let context =
         List.fold_left
           (fun context (key, _) ->
-            let bytes =
-              Base_samplers.uniform_bytes rng_state ~nbytes:value_size
+            let str =
+              Base_samplers.uniform_string rng_state ~nbytes:value_size
             in
-            write_storage context key bytes)
+            write_storage context key str)
           context
           keys_written_to
       in
diff --git a/src/lib_shell_benchmarks/io_helpers.ml b/src/lib_shell_benchmarks/io_helpers.ml
index 30e0556398c600a76f972d273714c87877264865..6d910aa4b8ef2875c920e8173e0d12b1f5278b51 100644
--- a/src/lib_shell_benchmarks/io_helpers.ml
+++ b/src/lib_shell_benchmarks/io_helpers.ml
@@ -106,8 +106,8 @@ let prepare_base_dir base_dir =
 
 (* This function updates the context with random bytes at a given depth. *)
 let initialize_key rng_state context path storage_size =
-  let bytes = Base_samplers.uniform_bytes rng_state ~nbytes:storage_size in
-  Tezos_protocol_environment.Context.add context path bytes
+  let str = Base_samplers.uniform_string rng_state ~nbytes:storage_size in
+  Tezos_protocol_environment.Context.add context path str
 
 let commit_and_reload base_dir index context =
   commit context
diff --git a/src/lib_shell_benchmarks/io_stats.ml b/src/lib_shell_benchmarks/io_stats.ml
index 27f53e80a86e95e34da3673cff2ebba814aee1c3..23f465f0c3a1edae9d4e41bde2a948bdf3d63b88 100644
--- a/src/lib_shell_benchmarks/io_stats.ml
+++ b/src/lib_shell_benchmarks/io_stats.ml
@@ -93,8 +93,8 @@ let load_tree context key =
     ~init:Io_helpers.Key_map.empty
     ~f:(fun path t tree ->
       match Context.Tree.kind t with
-      | `Value bytes ->
-          let len = Bytes.length bytes in
+      | `Value str ->
+          let len = String.length str in
           Lwt.return (Io_helpers.Key_map.insert path len tree)
       | `Tree ->
           Lwt.return tree)
diff --git a/src/lib_shell_services/block_services.ml b/src/lib_shell_services/block_services.ml
index cce1e7a8cca137d01a38a6f0ee6f0ebfe5c3bc24..1e29992960584bc28f8f28bd5c91a22037a2ebe0 100644
--- a/src/lib_shell_services/block_services.ml
+++ b/src/lib_shell_services/block_services.ml
@@ -196,13 +196,13 @@ let operation_list_quota_encoding =
     (fun (max_size, max_op) -> {max_size; max_op})
     (obj2 (req "max_size" int31) (opt "max_op" int31))
 
-type raw_context = Key of Bytes.t | Dir of (string * raw_context) list | Cut
+type raw_context = Key of string | Dir of (string * raw_context) list | Cut
 
 let rec pp_raw_context ppf = function
   | Cut ->
       Format.fprintf ppf "..."
   | Key v ->
-      Hex.pp ppf (Hex.of_bytes v)
+      Hex.pp ppf (Hex.of_string v)
   | Dir l ->
       Format.fprintf
         ppf
@@ -216,7 +216,7 @@ let raw_context_encoding =
       union
         [ case
             (Tag 0)
-            bytes
+            string
             ~title:"Key"
             (function Key k -> Some k | _ -> None)
             (fun k -> Key k);
diff --git a/src/lib_shell_services/block_services.mli b/src/lib_shell_services/block_services.mli
index 4842d5fd247adff3c625c40915147452a8f9d676..aaa7dc4e13456bb02cce2f8ad64b1fe9227d09b4 100644
--- a/src/lib_shell_services/block_services.mli
+++ b/src/lib_shell_services/block_services.mli
@@ -58,7 +58,7 @@ val live_blocks_path : ('a, 'b) RPC_path.t -> ('a, 'b) RPC_path.t
 
 type operation_list_quota = {max_size : int; max_op : int option}
 
-type raw_context = Key of Bytes.t | Dir of (string * raw_context) list | Cut
+type raw_context = Key of string | Dir of (string * raw_context) list | Cut
 
 val pp_raw_context : Format.formatter -> raw_context -> unit
 
diff --git a/src/lib_storage/context.ml b/src/lib_storage/context.ml
index 6d1fd6ec1d8260a8ce1de481c9ddda772e35c95b..f7978b8f902f5d06b0d8b80c5e4bb2808d0980e5 100644
--- a/src/lib_storage/context.ml
+++ b/src/lib_storage/context.ml
@@ -214,7 +214,7 @@ let data_key key = current_data_key @ key
 
 type key = string list
 
-type value = bytes
+type value = string
 
 type tree = Store.tree
 
@@ -257,10 +257,10 @@ let get_protocol v =
   | None ->
       assert false
   | Some data ->
-      Lwt.return (Protocol_hash.of_bytes_exn data)
+      Lwt.return (Protocol_hash.of_string_exn data)
 
 let add_protocol v key =
-  let key = Protocol_hash.to_bytes key in
+  let key = Protocol_hash.to_string key in
   raw_add v current_protocol_key key
 
 let get_test_chain v =
@@ -269,7 +269,11 @@ let get_test_chain v =
   | None ->
       Lwt.fail (Failure "Unexpected error (Context.get_test_chain)")
   | Some data -> (
-    match Data_encoding.Binary.of_bytes Test_chain_status.encoding data with
+    match
+      Data_encoding.Binary.of_bytes
+        Test_chain_status.encoding
+        (Bytes.unsafe_of_string data)
+    with
     | Error re ->
         Format.kasprintf
           (fun s -> Lwt.fail (Failure s))
@@ -281,7 +285,7 @@ let get_test_chain v =
 
 let add_test_chain v id =
   let id = Data_encoding.Binary.to_bytes_exn Test_chain_status.encoding id in
-  raw_add v current_test_chain_key id
+  raw_add v current_test_chain_key (Bytes.unsafe_to_string id)
 
 let remove_test_chain v = raw_remove v current_test_chain_key
 
@@ -295,7 +299,9 @@ let find_predecessor_block_metadata_hash v =
       Lwt.return_none
   | Some data -> (
     match
-      Data_encoding.Binary.of_bytes_opt Block_metadata_hash.encoding data
+      Data_encoding.Binary.of_bytes_opt
+        Block_metadata_hash.encoding
+        (Bytes.unsafe_of_string data)
     with
     | None ->
         Lwt.fail
@@ -308,7 +314,10 @@ let add_predecessor_block_metadata_hash v hash =
   let data =
     Data_encoding.Binary.to_bytes_exn Block_metadata_hash.encoding hash
   in
-  raw_add v current_predecessor_block_metadata_hash_key data
+  raw_add
+    v
+    current_predecessor_block_metadata_hash_key
+    (Bytes.unsafe_to_string data)
 
 let find_predecessor_ops_metadata_hash v =
   raw_find v current_predecessor_ops_metadata_hash_key
@@ -319,7 +328,7 @@ let find_predecessor_ops_metadata_hash v =
     match
       Data_encoding.Binary.of_bytes_opt
         Operation_metadata_list_list_hash.encoding
-        data
+        (Bytes.unsafe_of_string data)
     with
     | None ->
         Lwt.fail
@@ -334,7 +343,10 @@ let add_predecessor_ops_metadata_hash v hash =
       Operation_metadata_list_list_hash.encoding
       hash
   in
-  raw_add v current_predecessor_ops_metadata_hash_key data
+  raw_add
+    v
+    current_predecessor_ops_metadata_hash_key
+    (Bytes.unsafe_to_string data)
 
 (*-- Initialisation ----------------------------------------------------------*)
 
@@ -625,15 +637,15 @@ module Dumpable_context = struct
     conv
       (function
         | `Blob h ->
-            (`Blob, Context_hash.to_bytes (Hash.to_context_hash h))
+            (`Blob, Context_hash.to_string (Hash.to_context_hash h))
         | `Node h ->
-            (`Node, Context_hash.to_bytes (Hash.to_context_hash h)))
+            (`Node, Context_hash.to_string (Hash.to_context_hash h)))
       (function
         | (`Blob, h) ->
-            `Blob (Hash.of_context_hash (Context_hash.of_bytes_exn h))
+            `Blob (Hash.of_context_hash (Context_hash.of_string_exn h))
         | (`Node, h) ->
-            `Node (Hash.of_context_hash (Context_hash.of_bytes_exn h)))
-      (obj2 (req "kind" kind_encoding) (req "value" bytes))
+            `Node (Hash.of_context_hash (Context_hash.of_string_exn h)))
+      (obj2 (req "kind" kind_encoding) (req "value" string))
 
   let hash_equal (h1 : hash) (h2 : hash) = h1 = h2
 
@@ -760,7 +772,7 @@ module Dumpable_context = struct
     | Some t ->
         Store.Tree.add_tree tree key (t :> tree) >>= Lwt.return_some
 
-  let add_bytes (Batch (_, t, _)) b =
+  let add_string (Batch (_, t, _)) b =
     (* Save the contents in the store *)
     Store.save_contents t b >|= fun _ -> Store.Tree.of_contents b
 
@@ -843,9 +855,10 @@ let validate_context_hash_consistency_and_commit ~data_hash
     ~predecessor_ops_metadata_hash ~index =
   let data_hash = Hash.of_context_hash data_hash in
   let parents = List.map Hash.of_context_hash parents in
-  let protocol_value = Protocol_hash.to_bytes protocol_hash in
+  let protocol_value = Protocol_hash.to_string protocol_hash in
   let test_chain_value =
     Data_encoding.Binary.to_bytes_exn Test_chain_status.encoding test_chain
+    |> Bytes.unsafe_to_string
   in
   let tree = Store.Tree.empty in
   Store.Tree.add tree current_protocol_key protocol_value
@@ -855,7 +868,7 @@ let validate_context_hash_consistency_and_commit ~data_hash
   ( match predecessor_block_metadata_hash with
   | Some predecessor_block_metadata_hash ->
       let predecessor_block_metadata_hash_value =
-        Block_metadata_hash.to_bytes predecessor_block_metadata_hash
+        Block_metadata_hash.to_string predecessor_block_metadata_hash
       in
       Store.Tree.add
         tree
@@ -867,7 +880,7 @@ let validate_context_hash_consistency_and_commit ~data_hash
   ( match predecessor_ops_metadata_hash with
   | Some predecessor_ops_metadata_hash ->
       let predecessor_ops_metadata_hash_value =
-        Operation_metadata_list_list_hash.to_bytes
+        Operation_metadata_list_list_hash.to_string
           predecessor_ops_metadata_hash
       in
       Store.Tree.add
diff --git a/src/lib_storage/context_dump.ml b/src/lib_storage/context_dump.ml
index 9aa1dd145299d5017bce2dfdd344077fec0e2de0..7f669b2bad3a9a45800b9aac0a6346e474e857ac 100644
--- a/src/lib_storage/context_dump.ml
+++ b/src/lib_storage/context_dump.ml
@@ -169,7 +169,7 @@ module Make (I : Dump_interface) = struct
         pred_ops_metadata_hashes : Operation_metadata_hash.t list list option;
       }
     | Node of (string * I.hash) list
-    | Blob of bytes
+    | Blob of string
     | Proot of I.Pruned_block.t
     | Loot of I.Protocol_data.t
     | End
@@ -181,7 +181,7 @@ module Make (I : Dump_interface) = struct
     case
       ~title:"blob"
       (Tag (Char.code 'b'))
-      bytes
+      string
       (function Blob b -> Some b | _ -> None)
       (function b -> Blob b)
 
@@ -566,7 +566,7 @@ module Make (I : Dump_interface) = struct
     let read = ref 0 in
     let rbuf = ref (fd, Bytes.empty, 0, read) in
     (* Editing the repository *)
-    let add_blob t blob = I.add_bytes t blob >>= fun tree -> return tree in
+    let add_blob t blob = I.add_string t blob >>= fun tree -> return tree in
     let add_dir t keys =
       I.add_dir t keys
       >>= function
diff --git a/src/lib_storage/context_dump_intf.ml b/src/lib_storage/context_dump_intf.ml
index b001923fae6c0a6cb0ca3ce2ec1018a515ea6538..8a301aab21282fa8af59d4c15aeb7fb207d207e1 100644
--- a/src/lib_storage/context_dump_intf.ml
+++ b/src/lib_storage/context_dump_intf.ml
@@ -35,7 +35,7 @@ module type Dump_interface = sig
 
   type hash
 
-  type contents := bytes
+  type contents := string
 
   type step := string
 
@@ -141,7 +141,7 @@ module type Dump_interface = sig
 
   val update_context : context -> tree -> context
 
-  val add_bytes : batch -> bytes -> tree Lwt.t
+  val add_string : batch -> string -> tree Lwt.t
 
   val add_dir : batch -> (step * hash) list -> tree option Lwt.t
 end
diff --git a/src/lib_storage/encoding/context.ml b/src/lib_storage/encoding/context.ml
index 48cb996501d9e29c025b67c14235e6d0110390b0..24a3cb5d1994233ad2a13227bb7e5a1a58debda9 100644
--- a/src/lib_storage/encoding/context.ml
+++ b/src/lib_storage/encoding/context.ml
@@ -152,15 +152,15 @@ module Commit = struct
 end
 
 module Contents = struct
-  type t = bytes
+  type t = string
 
-  let ty = Irmin.Type.(pair (bytes_of `Int64) unit)
+  let ty = Irmin.Type.(pair (string_of `Int64) unit)
 
   let pre_hash_ty = Irmin.Type.(unstage (pre_hash ty))
 
   let pre_hash_v1 x = pre_hash_ty (x, ())
 
-  let t = Irmin.Type.(like bytes ~pre_hash:(stage @@ fun x -> pre_hash_v1 x))
+  let t = Irmin.Type.(like string ~pre_hash:(stage @@ fun x -> pre_hash_v1 x))
 
   let merge = Irmin.Merge.(idempotent (Irmin.Type.option t))
 end
diff --git a/src/lib_storage/encoding/context.mli b/src/lib_storage/encoding/context.mli
index f4d642474501275b370837cd0f03389e010f6f89..2c244821751e7f797889ec05b7556ec882ee4c77 100644
--- a/src/lib_storage/encoding/context.mli
+++ b/src/lib_storage/encoding/context.mli
@@ -33,7 +33,7 @@ module Hash : sig
   val of_context_hash : Context_hash.t -> t
 end
 
-module Contents : Irmin.Contents.S with type t = bytes
+module Contents : Irmin.Contents.S with type t = string
 
 module Metadata : Irmin.Metadata.S with type t = unit
 
diff --git a/src/lib_storage/helpers/context.ml b/src/lib_storage/helpers/context.ml
index c0fea728b768354ed41143f3326f9db0b312c530..4d507b26b5af02477235cbae1bc6de29c6c50b52 100644
--- a/src/lib_storage/helpers/context.ml
+++ b/src/lib_storage/helpers/context.ml
@@ -72,7 +72,7 @@ module Make_tree (Store : DB) = struct
           t
           init
 
-  type raw = [`Value of bytes | `Tree of raw TzString.Map.t]
+  type raw = [`Value of string | `Tree of raw TzString.Map.t]
 
   type concrete = Store.Tree.concrete
 
@@ -135,7 +135,7 @@ module Make_tree (Store : DB) = struct
             case
               ~title:"value"
               (Tag 1)
-              bytes
+              string
               (function `Value v -> Some v | `Tree _ -> None)
               (fun v -> `Value v) ])
 end
diff --git a/src/lib_storage/helpers/context.mli b/src/lib_storage/helpers/context.mli
index 095cb4153e35ac38b0afd3abc8ea8df76d4a3300..d5a3d84b6425c6b30b7cba2bf1fe8969d19de3d4 100644
--- a/src/lib_storage/helpers/context.mli
+++ b/src/lib_storage/helpers/context.mli
@@ -40,12 +40,12 @@ module Make_tree (DB : DB) : sig
     Tezos_storage_sigs.Context.TREE
       with type t := DB.t
        and type key := string list
-       and type value := bytes
+       and type value := DB.contents
        and type tree := DB.tree
 
   val empty : _ -> DB.tree
 
-  type raw = [`Value of bytes | `Tree of raw TzString.Map.t]
+  type raw = [`Value of DB.contents | `Tree of raw TzString.Map.t]
 
   val raw_encoding : raw Data_encoding.t
 
diff --git a/src/lib_storage/memory/context.ml b/src/lib_storage/memory/context.ml
index 00442991dcf4a9255102531d8e1cd558e6e47d32..34bf3d3b80119fb20ce7c95b0276f345e9dcefaf 100644
--- a/src/lib_storage/memory/context.ml
+++ b/src/lib_storage/memory/context.ml
@@ -34,9 +34,9 @@ type t = Store.tree
 
 type tree = t
 
-type key = string list
+type key = Path.t
 
-type value = bytes
+type value = Contents.t
 
 module Tree = Tezos_storage_helpers.Context.Make_tree (Store)
 include Tree
@@ -69,10 +69,10 @@ let get_protocol t =
   | None ->
       assert false
   | Some data ->
-      Lwt.return (Protocol_hash.of_bytes_exn data)
+      Lwt.return (Protocol_hash.of_string_exn data)
 
 let add_protocol t key =
-  let key = Protocol_hash.to_bytes key in
+  let key = Protocol_hash.to_string key in
   Tree.add t current_protocol_key key
 
 let empty = Store.Tree.empty
@@ -91,7 +91,7 @@ let concrete_encoding : Store.Tree.concrete Data_encoding.t =
           case
             ~title:"value"
             (Tag 1)
-            bytes
+            string
             (function `Contents (v, _) -> Some v | `Tree _ -> None)
             (fun v -> `Contents (v, ())) ])
 
diff --git a/src/lib_storage/sigs/context.ml b/src/lib_storage/sigs/context.ml
index 192e345457d148b727fe9184fae4c8b78ef6cbaf..dce3dfa1d29f6899f89b93e17d3ed3ed0c857fda 100644
--- a/src/lib_storage/sigs/context.ml
+++ b/src/lib_storage/sigs/context.ml
@@ -124,6 +124,8 @@ module type TREE = sig
   (** The type for context trees. *)
   type tree
 
+  include VIEW with type t := tree and type tree := tree
+
   (** [empty _] is the empty tree. *)
   val empty : t -> tree
 
@@ -132,7 +134,7 @@ module type TREE = sig
 
   (** [kind t] is [t]'s kind. It's either a tree node or a leaf
       value. *)
-  val kind : tree -> [`Value of bytes | `Tree]
+  val kind : tree -> [`Value of value | `Tree]
 
   (** [hash t] is [t]'s Merkle hash. *)
   val hash : tree -> Context_hash.t
@@ -140,8 +142,6 @@ module type TREE = sig
   (** [equal x y] is true iff [x] and [y] have the same Merkle hash. *)
   val equal : tree -> tree -> bool
 
-  include VIEW with type t := tree and type tree := tree
-
   (** {2 Caches} *)
 
   (** [clear ?depth t] clears all caches in the tree [t] for subtrees with a
@@ -151,7 +151,7 @@ module type TREE = sig
 end
 
 module type S = sig
-  include VIEW with type key = string list and type value = bytes
+  include VIEW with type key = string list and type value = string
 
   module Tree : sig
     include
@@ -164,7 +164,7 @@ module type S = sig
     (** {2 Data Encoding} *)
 
     (** The type for in-memory, raw contexts. *)
-    type raw = [`Value of bytes | `Tree of raw TzString.Map.t]
+    type raw = [`Value of value | `Tree of raw TzString.Map.t]
 
     (** [raw_encoding] is the data encoding for raw trees. *)
     val raw_encoding : raw Data_encoding.t
diff --git a/src/lib_storage/test/assert.ml b/src/lib_storage/test/assert.ml
index 0d05047a48c2eee4e9a5ddbf9c9ed291746f82e1..1b70bbe4424af15fe2c4f5576aafe98c12b7e768 100644
--- a/src/lib_storage/test/assert.ml
+++ b/src/lib_storage/test/assert.ml
@@ -111,15 +111,14 @@ let equal_raw_tree ?(msg = "") r1 r2 =
   let rec aux r1 r2 =
     match (r1, r2) with
     | (`Value v1, `Value v2) ->
-        equal_string ~msg (Bytes.to_string v1) (Bytes.to_string v2) ;
-        true
+        equal_string ~msg v1 v2 ; true
     | (`Tree t1, `Tree t2) ->
         if not (TzString.Map.equal aux t1 t2) then fail "<tree>" "<tree>" msg ;
         true
     | (`Tree _, `Value v) ->
-        fail "<tree>" (Bytes.to_string v) msg
+        fail "<tree>" v msg
     | (`Value v, `Tree _) ->
-        fail "<tree>" (Bytes.to_string v) msg
+        fail "<tree>" v msg
   in
   let (_ : bool) = aux r1 r2 in
   ()
diff --git a/src/lib_storage/test/test_context.ml b/src/lib_storage/test/test_context.ml
index 36a4a5b65e7b9ec556ebe3b7ed1591d54e2cbd46..5c3a435e1ca9c069b075f66b25a742598ab48814 100644
--- a/src/lib_storage/test/test_context.ml
+++ b/src/lib_storage/test/test_context.ml
@@ -71,11 +71,10 @@ let create_block2 idx genesis_commit =
   | None ->
       Assert.fail_msg "checkout genesis_block"
   | Some ctxt ->
-      add ctxt ["a"; "b"] (Bytes.of_string "Novembre")
+      add ctxt ["a"; "b"] "Novembre"
       >>= fun ctxt ->
-      add ctxt ["a"; "c"] (Bytes.of_string "Juin")
-      >>= fun ctxt ->
-      add ctxt ["version"] (Bytes.of_string "0.0") >>= fun ctxt -> commit ctxt
+      add ctxt ["a"; "c"] "Juin"
+      >>= fun ctxt -> add ctxt ["version"] "0.0" >>= commit
 
 let create_block3a idx block2_commit =
   checkout idx block2_commit
@@ -84,8 +83,7 @@ let create_block3a idx block2_commit =
       Assert.fail_msg "checkout block2"
   | Some ctxt ->
       remove ctxt ["a"; "b"]
-      >>= fun ctxt ->
-      add ctxt ["a"; "d"] (Bytes.of_string "Mars") >>= fun ctxt -> commit ctxt
+      >>= fun ctxt -> add ctxt ["a"; "d"] "Mars" >>= commit
 
 let create_block3b idx block2_commit =
   checkout idx block2_commit
@@ -94,9 +92,7 @@ let create_block3b idx block2_commit =
       Assert.fail_msg "checkout block3b"
   | Some ctxt ->
       remove ctxt ["a"; "c"]
-      >>= fun ctxt ->
-      add ctxt ["a"; "d"] (Bytes.of_string "Février")
-      >>= fun ctxt -> commit ctxt
+      >>= fun ctxt -> add ctxt ["a"; "d"] "Février" >>= commit
 
 type t = {
   idx : Context.index;
@@ -126,8 +122,6 @@ let wrap_context_init f _ () =
 
 (** Simple test *)
 
-let c = function None -> None | Some s -> Some (Bytes.to_string s)
-
 (** Checkout the context applied until [block2]. It is asserted that
     the following key-values are present:
     - (["version"], ["0.0"])
@@ -141,13 +135,13 @@ let test_simple {idx; block2; _} =
   | Some ctxt ->
       find ctxt ["version"]
       >>= fun version ->
-      Assert.equal_string_option ~msg:__LOC__ (c version) (Some "0.0") ;
+      Assert.equal_string_option ~msg:__LOC__ version (Some "0.0") ;
       find ctxt ["a"; "b"]
       >>= fun novembre ->
-      Assert.equal_string_option (Some "Novembre") (c novembre) ;
+      Assert.equal_string_option (Some "Novembre") novembre ;
       find ctxt ["a"; "c"]
       >>= fun juin ->
-      Assert.equal_string_option ~msg:__LOC__ (Some "Juin") (c juin) ;
+      Assert.equal_string_option ~msg:__LOC__ (Some "Juin") juin ;
       Lwt.return_unit
 
 let test_list {idx; block2; _} =
@@ -177,16 +171,16 @@ let test_continuation {idx; block3a; _} =
   | Some ctxt ->
       find ctxt ["version"]
       >>= fun version ->
-      Assert.equal_string_option ~msg:__LOC__ (Some "0.0") (c version) ;
+      Assert.equal_string_option ~msg:__LOC__ (Some "0.0") version ;
       find ctxt ["a"; "b"]
       >>= fun novembre ->
-      Assert.is_none ~msg:__LOC__ (c novembre) ;
+      Assert.is_none ~msg:__LOC__ novembre ;
       find ctxt ["a"; "c"]
       >>= fun juin ->
-      Assert.equal_string_option ~msg:__LOC__ (Some "Juin") (c juin) ;
+      Assert.equal_string_option ~msg:__LOC__ (Some "Juin") juin ;
       find ctxt ["a"; "d"]
       >>= fun mars ->
-      Assert.equal_string_option ~msg:__LOC__ (Some "Mars") (c mars) ;
+      Assert.equal_string_option ~msg:__LOC__ (Some "Mars") mars ;
       Lwt.return_unit
 
 (** Checkout the context applied until [block3b]. It is asserted that
@@ -204,16 +198,16 @@ let test_fork {idx; block3b; _} =
   | Some ctxt ->
       find ctxt ["version"]
       >>= fun version ->
-      Assert.equal_string_option ~msg:__LOC__ (Some "0.0") (c version) ;
+      Assert.equal_string_option ~msg:__LOC__ (Some "0.0") version ;
       find ctxt ["a"; "b"]
       >>= fun novembre ->
-      Assert.equal_string_option ~msg:__LOC__ (Some "Novembre") (c novembre) ;
+      Assert.equal_string_option ~msg:__LOC__ (Some "Novembre") novembre ;
       find ctxt ["a"; "c"]
       >>= fun juin ->
-      Assert.is_none ~msg:__LOC__ (c juin) ;
+      Assert.is_none ~msg:__LOC__ juin ;
       find ctxt ["a"; "d"]
       >>= fun mars ->
-      Assert.equal_string_option ~msg:__LOC__ (Some "Février") (c mars) ;
+      Assert.equal_string_option ~msg:__LOC__ (Some "Février") mars ;
       Lwt.return_unit
 
 (** Checkout the context at [genesis] and explicitly replay
@@ -224,33 +218,33 @@ let test_replay {idx; genesis; _} =
   | None ->
       Assert.fail_msg "checkout genesis_block"
   | Some ctxt0 ->
-      add ctxt0 ["version"] (Bytes.of_string "0.0")
+      add ctxt0 ["version"] "0.0"
       >>= fun ctxt1 ->
-      add ctxt1 ["a"; "b"] (Bytes.of_string "Novembre")
+      add ctxt1 ["a"; "b"] "Novembre"
       >>= fun ctxt2 ->
-      add ctxt2 ["a"; "c"] (Bytes.of_string "Juin")
+      add ctxt2 ["a"; "c"] "Juin"
       >>= fun ctxt3 ->
-      add ctxt3 ["a"; "d"] (Bytes.of_string "July")
+      add ctxt3 ["a"; "d"] "July"
       >>= fun ctxt4a ->
-      add ctxt3 ["a"; "d"] (Bytes.of_string "Juillet")
+      add ctxt3 ["a"; "d"] "Juillet"
       >>= fun ctxt4b ->
-      add ctxt4a ["a"; "b"] (Bytes.of_string "November")
+      add ctxt4a ["a"; "b"] "November"
       >>= fun ctxt5a ->
       find ctxt4a ["a"; "b"]
       >>= fun novembre ->
-      Assert.equal_string_option ~msg:__LOC__ (Some "Novembre") (c novembre) ;
+      Assert.equal_string_option ~msg:__LOC__ (Some "Novembre") novembre ;
       find ctxt5a ["a"; "b"]
       >>= fun november ->
-      Assert.equal_string_option ~msg:__LOC__ (Some "November") (c november) ;
+      Assert.equal_string_option ~msg:__LOC__ (Some "November") november ;
       find ctxt5a ["a"; "d"]
       >>= fun july ->
-      Assert.equal_string_option ~msg:__LOC__ (Some "July") (c july) ;
+      Assert.equal_string_option ~msg:__LOC__ (Some "July") july ;
       find ctxt4b ["a"; "b"]
       >>= fun novembre ->
-      Assert.equal_string_option ~msg:__LOC__ (Some "Novembre") (c novembre) ;
+      Assert.equal_string_option ~msg:__LOC__ (Some "Novembre") novembre ;
       find ctxt4b ["a"; "d"]
       >>= fun juillet ->
-      Assert.equal_string_option ~msg:__LOC__ (Some "Juillet") (c juillet) ;
+      Assert.equal_string_option ~msg:__LOC__ (Some "Juillet") juillet ;
       Lwt.return_unit
 
 let fold_keys s root ~init ~f =
@@ -285,7 +279,7 @@ let steps =
 [@@ocamlformat "disable"]
 
 let bindings =
-  let zero = Bytes.make 10 '0' in
+  let zero = Bytes.make 10 '0' |> Bytes.unsafe_to_string in
   List.map (fun x -> (["root"; x], zero)) steps
 
 let test_fold_keys {idx; genesis; _} =
@@ -294,15 +288,15 @@ let test_fold_keys {idx; genesis; _} =
   | None ->
       Assert.fail_msg "checkout genesis_block"
   | Some ctxt ->
-      add ctxt ["a"; "b"] (Bytes.of_string "Novembre")
+      add ctxt ["a"; "b"] "Novembre"
       >>= fun ctxt ->
-      add ctxt ["a"; "c"] (Bytes.of_string "Juin")
+      add ctxt ["a"; "c"] "Juin"
       >>= fun ctxt ->
-      add ctxt ["a"; "d"; "e"] (Bytes.of_string "Septembre")
+      add ctxt ["a"; "d"; "e"] "Septembre"
       >>= fun ctxt ->
-      add ctxt ["f"] (Bytes.of_string "Avril")
+      add ctxt ["f"] "Avril"
       >>= fun ctxt ->
-      add ctxt ["g"; "h"] (Bytes.of_string "Avril")
+      add ctxt ["g"; "h"] "Avril"
       >>= fun ctxt ->
       keys ctxt []
       >>= fun l ->
@@ -345,8 +339,8 @@ let test_fold {idx; genesis; _} =
   | None ->
       Assert.fail_msg "checkout genesis_block"
   | Some ctxt ->
-      let foo1 = Bytes.of_string "foo1" in
-      let foo2 = Bytes.of_string "foo2" in
+      let foo1 = "foo1" in
+      let foo2 = "foo2" in
       add ctxt ["foo"; "toto"] foo1
       >>= fun ctxt ->
       add ctxt ["foo"; "bar"; "toto"] foo2
@@ -394,8 +388,8 @@ let test_trees {idx; genesis; _} =
           assert (List.length k = 1) ;
           Assert.fail_msg "empty")
       >>= fun () ->
-      let foo1 = Bytes.of_string "foo1" in
-      let foo2 = Bytes.of_string "foo2" in
+      let foo1 = "foo1" in
+      let foo2 = "foo2" in
       Tree.empty ctxt
       |> fun v1 ->
       Tree.add v1 ["foo"; "toto"] foo1
@@ -440,10 +434,10 @@ let test_trees {idx; genesis; _} =
       >>= fun v1 ->
       Tree.find v1 ["foo"; "bar"; "toto"]
       >>= fun v ->
-      Assert.equal_bytes_option ~msg:__LOC__ None v ;
+      Assert.equal_string_option ~msg:__LOC__ None v ;
       Tree.find v1 ["foo"; "toto"]
       >>= fun v ->
-      Assert.equal_bytes_option ~msg:__LOC__ (Some foo1) v ;
+      Assert.equal_string_option ~msg:__LOC__ (Some foo1) v ;
       Tree.empty ctxt
       |> fun v1 ->
       Tree.add v1 ["foo"; "1"] foo1
@@ -456,7 +450,7 @@ let test_trees {idx; genesis; _} =
       >>= fun v1 ->
       Tree.find v1 ["foo"; "1"]
       >>= fun v ->
-      Assert.equal_bytes_option ~msg:__LOC__ None v ;
+      Assert.equal_string_option ~msg:__LOC__ None v ;
       Tree.remove v1 []
       >>= fun v1 ->
       Assert.equal_bool ~msg:__LOC__ true (Tree.is_empty v1) ;
@@ -468,8 +462,8 @@ let test_raw {idx; genesis; _} =
   | None ->
       Assert.fail_msg "checkout genesis_block"
   | Some ctxt ->
-      let foo1 = Bytes.of_string "foo1" in
-      let foo2 = Bytes.of_string "foo2" in
+      let foo1 = "foo1" in
+      let foo2 = "foo2" in
       add ctxt ["foo"; "toto"] foo1
       >>= fun ctxt ->
       add ctxt ["foo"; "bar"; "toto"] foo2
@@ -495,8 +489,8 @@ let test_encoding {idx; genesis; _} =
   | None ->
       Assert.fail_msg "checkout genesis_block"
   | Some ctxt ->
-      let foo1 = Bytes.of_string "foo1" in
-      let foo2 = Bytes.of_string "foo2" in
+      let foo1 = "foo1" in
+      let foo2 = "foo2" in
       add ctxt ["a"; string 7] foo1
       >>= fun ctxt ->
       add ctxt ["a"; string 8] foo2
diff --git a/src/proto_006_PsCARTHA/lib_client/proxy.ml b/src/proto_006_PsCARTHA/lib_client/proxy.ml
index b88a2ce405c3222a7b05b96c820c01118fcb70b6..e86b77b7b3813774d9e35c956fcb2910c2039d1a 100644
--- a/src/proto_006_PsCARTHA/lib_client/proxy.ml
+++ b/src/proto_006_PsCARTHA/lib_client/proxy.ml
@@ -110,10 +110,7 @@ let initial_context (rpc_context : RPC_context.json)
   end in
   let empty = Proxy_context.empty @@ Some (module N) in
   let version_value = "carthage_006" in
-  Tezos_protocol_environment.Context.add
-    empty
-    ["version"]
-    (Bytes.of_string version_value)
+  Tezos_protocol_environment.Context.add empty ["version"] version_value
 
 let init_env_rpc_context (_printer : Tezos_client_base.Client_context.printer)
     (rpc_context : RPC_context.json)
diff --git a/src/proto_007_PsDELPH1/lib_client/mockup.ml b/src/proto_007_PsDELPH1/lib_client/mockup.ml
index 5d955b9021ac96f9267808243be8bafef59d9806..b3268a0c8633d4295eb8aab3f0e1fda1d7251379 100644
--- a/src/proto_007_PsDELPH1/lib_client/mockup.ml
+++ b/src/proto_007_PsDELPH1/lib_client/mockup.ml
@@ -384,10 +384,11 @@ let initial_context (header : Block_header.shell_header)
   let json = Default_parameters.json_of_parameters parameters in
   let proto_params =
     Data_encoding.Binary.to_bytes_exn Data_encoding.json json
+    |> Bytes.unsafe_to_string
   in
   Tezos_protocol_environment.Context.(
     let empty = Memory_context.empty in
-    add empty ["version"] (Bytes.of_string "genesis")
+    add empty ["version"] "genesis"
     >>= fun ctxt -> add ctxt ["protocol_parameters"] proto_params)
   >>= fun ctxt ->
   Protocol.Main.init ctxt header
diff --git a/src/proto_007_PsDELPH1/lib_client/proxy.ml b/src/proto_007_PsDELPH1/lib_client/proxy.ml
index ec3c16a2d2759ad2dddbdb8b0ebb15e61288ae35..29c0dca1217cda770bdffe7df566fd7f22304983 100644
--- a/src/proto_007_PsDELPH1/lib_client/proxy.ml
+++ b/src/proto_007_PsDELPH1/lib_client/proxy.ml
@@ -110,10 +110,7 @@ let initial_context (rpc_context : RPC_context.json)
   end in
   let empty = Proxy_context.empty @@ Some (module N) in
   let version_value = "delphi_007" in
-  Tezos_protocol_environment.Context.add
-    empty
-    ["version"]
-    (Bytes.of_string version_value)
+  Tezos_protocol_environment.Context.add empty ["version"] version_value
 
 let init_env_rpc_context (_printer : Tezos_client_base.Client_context.printer)
     (rpc_context : RPC_context.json)
diff --git a/src/proto_007_PsDELPH1/lib_protocol/test/helpers/block.ml b/src/proto_007_PsDELPH1/lib_protocol/test/helpers/block.ml
index 2406ffbdd150c23444affaf445644353a1afb789..860a4fe3e510c42e0c47b6858a9a013d90ecbec1 100644
--- a/src/proto_007_PsDELPH1/lib_protocol/test/helpers/block.ml
+++ b/src/proto_007_PsDELPH1/lib_protocol/test/helpers/block.ml
@@ -262,10 +262,11 @@ let initial_context ?(with_commitments = false) constants header
   let json = Default_parameters.json_of_parameters parameters in
   let proto_params =
     Data_encoding.Binary.to_bytes_exn Data_encoding.json json
+    |> Bytes.unsafe_to_string
   in
   Tezos_protocol_environment.Context.(
     let empty = Memory_context.empty in
-    add empty ["version"] (Bytes.of_string "genesis")
+    add empty ["version"] "genesis"
     >>= fun ctxt -> add ctxt protocol_param_key proto_params)
   >>= fun ctxt ->
   Main.init ctxt header >|= Environment.wrap_error
@@ -289,10 +290,11 @@ let genesis_with_parameters parameters =
   let json = Default_parameters.json_of_parameters parameters in
   let proto_params =
     Data_encoding.Binary.to_bytes_exn Data_encoding.json json
+    |> Bytes.unsafe_to_string
   in
   Tezos_protocol_environment.Context.(
     let empty = Memory_context.empty in
-    add empty ["version"] (Bytes.of_string "genesis")
+    add empty ["version"] "genesis"
     >>= fun ctxt -> add ctxt protocol_param_key proto_params)
   >>= fun ctxt ->
   Main.init ctxt shell >|= Environment.wrap_error
diff --git a/src/proto_008_PtEdoTez/lib_client/mockup.ml b/src/proto_008_PtEdoTez/lib_client/mockup.ml
index 68ca698f2fbe7766d43c96a5a69d4069cfdb4e14..014f51e7a78aa7ceaca4b07a1d8f9da521be4532 100644
--- a/src/proto_008_PtEdoTez/lib_client/mockup.ml
+++ b/src/proto_008_PtEdoTez/lib_client/mockup.ml
@@ -384,10 +384,11 @@ let initial_context (header : Block_header.shell_header)
   let json = Default_parameters.json_of_parameters parameters in
   let proto_params =
     Data_encoding.Binary.to_bytes_exn Data_encoding.json json
+    |> Bytes.unsafe_to_string
   in
   Tezos_protocol_environment.Context.(
     let empty = Memory_context.empty in
-    add empty ["version"] (Bytes.of_string "genesis")
+    add empty ["version"] "genesis"
     >>= fun ctxt -> add ctxt ["protocol_parameters"] proto_params)
   >>= fun ctxt ->
   Protocol.Main.init ctxt header
diff --git a/src/proto_008_PtEdoTez/lib_client/proxy.ml b/src/proto_008_PtEdoTez/lib_client/proxy.ml
index 1eee7831d3bdee4dfa5daeb96566944ac904bfd1..c407f3ce949f361a92f0ad9768e2d49e2e9339e4 100644
--- a/src/proto_008_PtEdoTez/lib_client/proxy.ml
+++ b/src/proto_008_PtEdoTez/lib_client/proxy.ml
@@ -110,10 +110,7 @@ let initial_context (rpc_context : RPC_context.json)
   end in
   let empty = Proxy_context.empty @@ Some (module N) in
   let version_value = "edo_008" in
-  Tezos_protocol_environment.Context.add
-    empty
-    ["version"]
-    (Bytes.of_string version_value)
+  Tezos_protocol_environment.Context.add empty ["version"] version_value
 
 let init_env_rpc_context (_printer : Tezos_client_base.Client_context.printer)
     (rpc_context : RPC_context.json)
diff --git a/src/proto_008_PtEdoTez/lib_protocol/test/helpers/block.ml b/src/proto_008_PtEdoTez/lib_protocol/test/helpers/block.ml
index 50f981aae4ed9ca04590699ea234b8e0cd17da2a..d0c2e53c5113b9fbd1cb202470fa1589d200451c 100644
--- a/src/proto_008_PtEdoTez/lib_protocol/test/helpers/block.ml
+++ b/src/proto_008_PtEdoTez/lib_protocol/test/helpers/block.ml
@@ -263,10 +263,11 @@ let initial_context ?(with_commitments = false) constants header
   let json = Default_parameters.json_of_parameters parameters in
   let proto_params =
     Data_encoding.Binary.to_bytes_exn Data_encoding.json json
+    |> Bytes.unsafe_to_string
   in
   Tezos_protocol_environment.Context.(
     let empty = Memory_context.empty in
-    add empty ["version"] (Bytes.of_string "genesis")
+    add empty ["version"] "genesis"
     >>= fun ctxt -> add ctxt protocol_param_key proto_params)
   >>= fun ctxt ->
   Main.init ctxt header >|= Environment.wrap_error
@@ -290,10 +291,11 @@ let genesis_with_parameters parameters =
   let json = Default_parameters.json_of_parameters parameters in
   let proto_params =
     Data_encoding.Binary.to_bytes_exn Data_encoding.json json
+    |> Bytes.unsafe_to_string
   in
   Tezos_protocol_environment.Context.(
     let empty = Memory_context.empty in
-    add empty ["version"] (Bytes.of_string "genesis")
+    add empty ["version"] "genesis"
     >>= fun ctxt -> add ctxt protocol_param_key proto_params)
   >>= fun ctxt ->
   Main.init ctxt shell >|= Environment.wrap_error
diff --git a/src/proto_alpha/lib_client/mockup.ml b/src/proto_alpha/lib_client/mockup.ml
index d13fb76a4ca1a189184ddb74fa1f121fcd7564f7..4dae1bf5c86f1612f1a5a1e93bb922f727290b87 100644
--- a/src/proto_alpha/lib_client/mockup.ml
+++ b/src/proto_alpha/lib_client/mockup.ml
@@ -359,10 +359,11 @@ let initial_context (header : Block_header.shell_header)
   let json = Default_parameters.json_of_parameters parameters in
   let proto_params =
     Data_encoding.Binary.to_bytes_exn Data_encoding.json json
+    |> Bytes.to_string
   in
   Tezos_protocol_environment.Context.(
     let empty = Memory_context.empty in
-    add empty ["version"] (Bytes.of_string "genesis")
+    add empty ["version"] "genesis"
     >>= fun ctxt -> add ctxt ["protocol_parameters"] proto_params)
   >>= fun ctxt ->
   Protocol.Main.init ctxt header
diff --git a/src/proto_alpha/lib_client/proxy.ml b/src/proto_alpha/lib_client/proxy.ml
index 3ced2424ce0a93801374a10e1d96f8f3eecb8ae2..af104c322a9cbeeaa5e24d54d649b8af562d4a1d 100644
--- a/src/proto_alpha/lib_client/proxy.ml
+++ b/src/proto_alpha/lib_client/proxy.ml
@@ -110,10 +110,7 @@ let initial_context (rpc_context : RPC_context.json)
   end in
   let empty = Proxy_context.empty @@ Some (module N) in
   let version_value = "alpha_current" in
-  Tezos_protocol_environment.Context.add
-    empty
-    ["version"]
-    (Bytes.of_string version_value)
+  Tezos_protocol_environment.Context.add empty ["version"] version_value
 
 let init_env_rpc_context (_printer : Tezos_client_base.Client_context.printer)
     (rpc_context : RPC_context.json)
diff --git a/src/proto_alpha/lib_protocol/raw_context.ml b/src/proto_alpha/lib_protocol/raw_context.ml
index 859a5ede8e65fdb326664482d4e9d5216f1ff3df..c4026437983f6c3d8b1430ccc650d1aca9f99e87 100644
--- a/src/proto_alpha/lib_protocol/raw_context.ml
+++ b/src/proto_alpha/lib_protocol/raw_context.ml
@@ -598,8 +598,12 @@ let get_first_level ctxt =
   >|= function
   | None ->
       storage_error (Missing_key (first_level_key, Get))
-  | Some bytes -> (
-    match Data_encoding.Binary.of_bytes Raw_level_repr.encoding bytes with
+  | Some str -> (
+    match
+      Data_encoding.Binary.of_bytes
+        Raw_level_repr.encoding
+        (Bytes.of_string str)
+    with
     | None ->
         storage_error (Corrupted_data first_level_key)
     | Some level ->
@@ -609,9 +613,9 @@ let set_first_level ctxt level =
   let bytes =
     Data_encoding.Binary.to_bytes_exn Raw_level_repr.encoding level
   in
-  Context.add ctxt first_level_key bytes >|= ok
+  Context.add ctxt first_level_key (Bytes.to_string bytes) >|= ok
 
-type error += Failed_to_parse_parameter of bytes
+type error += Failed_to_parse_parameter of string
 
 type error += Failed_to_decode_parameter of Data_encoding.json * string
 
@@ -621,12 +625,12 @@ let () =
     ~id:"context.failed_to_parse_parameter"
     ~title:"Failed to parse parameter"
     ~description:"The protocol parameters are not valid JSON."
-    ~pp:(fun ppf bytes ->
+    ~pp:(fun ppf string ->
       Format.fprintf
         ppf
         "@[<v 2>Cannot parse the protocol parameter:@ %s@]"
-        (Bytes.to_string bytes))
-    Data_encoding.(obj1 (req "contents" bytes))
+        string)
+    Data_encoding.(obj1 (req "contents" string))
     (function Failed_to_parse_parameter data -> Some data | _ -> None)
     (fun data -> Failed_to_parse_parameter data) ;
   register_error_kind
@@ -651,10 +655,12 @@ let get_proto_param ctxt =
   >>= function
   | None ->
       failwith "Missing protocol parameters."
-  | Some bytes -> (
-    match Data_encoding.Binary.of_bytes Data_encoding.json bytes with
+  | Some str -> (
+    match
+      Data_encoding.Binary.of_bytes Data_encoding.json (Bytes.of_string str)
+    with
     | None ->
-        fail (Failed_to_parse_parameter bytes)
+        fail (Failed_to_parse_parameter str)
     | Some json -> (
         Context.remove ctxt protocol_param_key
         >|= fun ctxt ->
@@ -676,16 +682,18 @@ let add_constants ctxt constants =
       Constants_repr.parametric_encoding
       constants
   in
-  Context.add ctxt constants_key bytes
+  Context.add ctxt constants_key (Bytes.to_string bytes)
 
 let get_constants ctxt =
   Context.find ctxt constants_key
   >|= function
   | None ->
       failwith "Internal error: cannot read constants in context."
-  | Some bytes -> (
+  | Some str -> (
     match
-      Data_encoding.Binary.of_bytes Constants_repr.parametric_encoding bytes
+      Data_encoding.Binary.of_bytes
+        Constants_repr.parametric_encoding
+        (Bytes.of_string str)
     with
     | None ->
         failwith "Internal error: cannot parse constants in context."
@@ -704,8 +712,7 @@ let check_inited ctxt =
   >|= function
   | None ->
       failwith "Internal error: un-initialized context."
-  | Some bytes ->
-      let s = Bytes.to_string bytes in
+  | Some s ->
       if Compare.String.(s = version_value) then ok_unit
       else storage_error (Incompatible_protocol_version s)
 
@@ -762,8 +769,7 @@ let check_and_update_protocol_version ctxt =
         | None ->
             failwith
               "Internal error: un-initialized context in check_first_block."
-        | Some bytes ->
-            let s = Bytes.to_string bytes in
+        | Some s ->
             if Compare.String.(s = version_value) then
               failwith "Internal error: previously initialized context."
             else if Compare.String.(s = "genesis") then
@@ -772,7 +778,7 @@ let check_and_update_protocol_version ctxt =
             else if Compare.String.(s = "edo_008") then return (Edo_008, ctxt)
             else Lwt.return @@ storage_error (Incompatible_protocol_version s))
   >>=? fun (previous_proto, ctxt) ->
-  Context.add ctxt version_key (Bytes.of_string version_value)
+  Context.add ctxt version_key version_value
   >|= fun ctxt -> ok (previous_proto, ctxt)
 
 let prepare_first_block ~level ~timestamp ~fitness ctxt =
@@ -796,7 +802,7 @@ let activate ctxt h = Updater.activate (context ctxt) h >|= update_context ctxt
 
 type key = string list
 
-type value = bytes
+type value = string
 
 type tree = Context.tree
 
diff --git a/src/proto_alpha/lib_protocol/raw_context.mli b/src/proto_alpha/lib_protocol/raw_context.mli
index f06b2fec7ccafcbeb62e018344a38f22c53df3cf..74563e7e64244ee1e7848a2bb496efcb7193b705 100644
--- a/src/proto_alpha/lib_protocol/raw_context.mli
+++ b/src/proto_alpha/lib_protocol/raw_context.mli
@@ -38,7 +38,7 @@ type storage_error =
 
 type error += Storage_error of storage_error
 
-type error += Failed_to_parse_parameter of bytes
+type error += Failed_to_parse_parameter of string
 
 type error += Failed_to_decode_parameter of Data_encoding.json * string
 
@@ -151,7 +151,7 @@ val unset_origination_nonce : t -> t
 
 type key = string list
 
-type value = bytes
+type value = string
 
 type tree
 
diff --git a/src/proto_alpha/lib_protocol/raw_context_intf.ml b/src/proto_alpha/lib_protocol/raw_context_intf.ml
index b82f376e9b55fd88bc83f2fa675a282a726ecdc5..8177a4d852ab2cbf503094360ce76796e70c3355 100644
--- a/src/proto_alpha/lib_protocol/raw_context_intf.ml
+++ b/src/proto_alpha/lib_protocol/raw_context_intf.ml
@@ -42,7 +42,7 @@ module type VIEW = sig
   type key = string list
 
   (** The type for context values. *)
-  type value = bytes
+  type value = string
 
   (** {2 Getters} *)
 
@@ -190,6 +190,8 @@ module type TREE = sig
   (** The type for context trees. *)
   type tree
 
+  include VIEW with type t := tree and type tree := tree
+
   (** [empty _] is the empty tree. *)
   val empty : t -> tree
 
@@ -198,7 +200,7 @@ module type TREE = sig
 
   (** [kind t] is [t]'s kind. It's either a tree node or a leaf
       value. *)
-  val kind : tree -> [`Value of bytes | `Tree]
+  val kind : tree -> [`Value of value | `Tree]
 
   (** [hash t] is [t]'s Merkle hash. *)
   val hash : tree -> Context_hash.t
@@ -206,8 +208,6 @@ module type TREE = sig
   (** [equal x y] is true iff [x] and [y] have the same Merkle hash. *)
   val equal : tree -> tree -> bool
 
-  include VIEW with type t := tree and type tree := tree
-
   (** {2 Caches} *)
 
   (** [clear ?depth t] clears all caches in the tree [t] for subtrees with a
diff --git a/src/proto_alpha/lib_protocol/storage_functors.ml b/src/proto_alpha/lib_protocol/storage_functors.ml
index 2971e5ea2200ed1c8a5a0c70da0c056ef4e9be53..8d337af7b59485f88a25e64def6db3a27acdd9e2 100644
--- a/src/proto_alpha/lib_protocol/storage_functors.ml
+++ b/src/proto_alpha/lib_protocol/storage_functors.ml
@@ -35,31 +35,31 @@ module Ghost = struct
 end
 
 module Make_encoder (V : VALUE) = struct
-  let of_bytes ~key b =
-    match Data_encoding.Binary.of_bytes V.encoding b with
+  let of_string ~key b =
+    match Data_encoding.Binary.of_bytes V.encoding (Bytes.of_string b) with
     | None ->
         error (Raw_context.Storage_error (Corrupted_data (key ())))
     | Some v ->
         Ok v
 
-  let to_bytes v =
+  let to_string v =
     match Data_encoding.Binary.to_bytes V.encoding v with
     | Some b ->
-        b
+        Bytes.to_string b
     | None ->
-        Bytes.empty
+        ""
 end
 
 let len_name = "len"
 
 let data_name = "data"
 
-let encode_len_value bytes =
-  let length = Bytes.length bytes in
-  Data_encoding.(Binary.to_bytes_exn int31) length
+let encode_len_value str =
+  let length = String.length str in
+  Data_encoding.(Binary.to_bytes_exn int31) length |> Bytes.to_string
 
 let decode_len_value key len =
-  match Data_encoding.(Binary.of_bytes int31) len with
+  match Data_encoding.(Binary.of_bytes int31) (Bytes.of_string len) with
   | None ->
       error (Raw_context.Storage_error (Corrupted_data key))
   | Some len ->
@@ -150,7 +150,7 @@ struct
     C.get t N.name
     >>=? fun b ->
     let key () = C.absolute_key t N.name in
-    Lwt.return (of_bytes ~key b)
+    Lwt.return (of_string ~key b)
 
   let find t =
     C.find t N.name
@@ -159,16 +159,16 @@ struct
         ok_none
     | Some b ->
         let key () = C.absolute_key t N.name in
-        of_bytes ~key b >|? fun v -> Some v
+        of_string ~key b >|? fun v -> Some v
 
-  let init t v = C.init t N.name (to_bytes v) >|=? fun t -> C.project t
+  let init t v = C.init t N.name (to_string v) >|=? fun t -> C.project t
 
-  let update t v = C.update t N.name (to_bytes v) >|=? fun t -> C.project t
+  let update t v = C.update t N.name (to_string v) >|=? fun t -> C.project t
 
-  let add t v = C.add t N.name (to_bytes v) >|= fun t -> C.project t
+  let add t v = C.add t N.name (to_string v) >|= fun t -> C.project t
 
   let add_or_remove t v =
-    C.add_or_remove t N.name (Option.map to_bytes v) >|= fun t -> C.project t
+    C.add_or_remove t N.name (Option.map to_string v) >|= fun t -> C.project t
 
   let remove t = C.remove t N.name >|= fun t -> C.project t
 
@@ -231,7 +231,7 @@ module Make_data_set_storage (C : Raw_context.T) (I : INDEX) :
 
   type elt = I.t
 
-  let inited = Bytes.of_string "inited"
+  let inited = "inited"
 
   let mem s i = C.mem s (I.to_path i [])
 
@@ -286,7 +286,7 @@ module Make_indexed_data_storage (C : Raw_context.T) (I : INDEX) (V : VALUE) :
     C.get s (I.to_path i [])
     >>=? fun b ->
     let key () = C.absolute_key s (I.to_path i []) in
-    Lwt.return (of_bytes ~key b)
+    Lwt.return (of_string ~key b)
 
   let find s i =
     C.find s (I.to_path i [])
@@ -295,19 +295,19 @@ module Make_indexed_data_storage (C : Raw_context.T) (I : INDEX) (V : VALUE) :
         ok_none
     | Some b ->
         let key () = C.absolute_key s (I.to_path i []) in
-        of_bytes ~key b >|? fun v -> Some v
+        of_string ~key b >|? fun v -> Some v
 
   let update s i v =
-    C.update s (I.to_path i []) (to_bytes v) >|=? fun t -> C.project t
+    C.update s (I.to_path i []) (to_string v) >|=? fun t -> C.project t
 
   let init s i v =
-    C.init s (I.to_path i []) (to_bytes v) >|=? fun t -> C.project t
+    C.init s (I.to_path i []) (to_string v) >|=? fun t -> C.project t
 
   let add s i v =
-    C.add s (I.to_path i []) (to_bytes v) >|= fun t -> C.project t
+    C.add s (I.to_path i []) (to_string v) >|= fun t -> C.project t
 
   let add_or_remove s i v =
-    C.add_or_remove s (I.to_path i []) (Option.map to_bytes v)
+    C.add_or_remove s (I.to_path i []) (Option.map to_string v)
     >|= fun t -> C.project t
 
   let remove s i = C.remove s (I.to_path i []) >|= fun t -> C.project t
@@ -326,7 +326,7 @@ module Make_indexed_data_storage (C : Raw_context.T) (I : INDEX) (V : VALUE) :
               assert false
           | Some path -> (
               let key () = C.absolute_key s file in
-              match of_bytes ~key v with
+              match of_string ~key v with
               | Ok v ->
                   f path v acc
               | Error _ ->
@@ -407,14 +407,14 @@ struct
      to bytes. It would be cleaner for users of this functor to provide
      gas costs for the encoding. *)
   let consume_serialize_write_gas set c i v =
-    let bytes = to_bytes v in
-    let len = Bytes.length bytes in
+    let str = to_string v in
+    let len = String.length str in
     C.consume_gas c (Gas_limit_repr.alloc_mbytes_cost len)
     >>?= fun c ->
     let cost = Storage_costs.write_access ~written_bytes:len in
     C.consume_gas c cost
     >>?= fun c ->
-    set c (len_key i) (encode_len_value bytes) >|=? fun c -> (c, bytes)
+    set c (len_key i) (encode_len_value str) >|=? fun c -> (c, str)
 
   let consume_remove_gas del c i =
     C.consume_gas c (Storage_costs.write_access ~written_bytes:0)
@@ -431,7 +431,7 @@ struct
     C.get s (data_key i)
     >>=? fun b ->
     let key () = C.absolute_key s (data_key i) in
-    Lwt.return (of_bytes ~key b >|? fun v -> (C.project s, v))
+    Lwt.return (of_string ~key b >|? fun v -> (C.project s, v))
 
   let find s i =
     let key = data_key i in
@@ -446,18 +446,18 @@ struct
     existing_size s i
     >>=? fun (prev_size, _) ->
     consume_serialize_write_gas C.update s i v
-    >>=? fun (s, bytes) ->
-    C.update s (data_key i) bytes
+    >>=? fun (s, str) ->
+    C.update s (data_key i) str
     >|=? fun t ->
-    let size_diff = Bytes.length bytes - prev_size in
+    let size_diff = String.length str - prev_size in
     (C.project t, size_diff)
 
   let init s i v =
     consume_serialize_write_gas C.init s i v
-    >>=? fun (s, bytes) ->
-    C.init s (data_key i) bytes
+    >>=? fun (s, str) ->
+    C.init s (data_key i) str
     >|=? fun t ->
-    let size = Bytes.length bytes in
+    let size = String.length str in
     (C.project t, size)
 
   let add s i v =
@@ -465,10 +465,10 @@ struct
     existing_size s i
     >>=? fun (prev_size, existed) ->
     consume_serialize_write_gas add s i v
-    >>=? fun (s, bytes) ->
-    add s (data_key i) bytes
+    >>=? fun (s, str) ->
+    add s (data_key i) str
     >|=? fun t ->
-    let size_diff = Bytes.length bytes - prev_size in
+    let size_diff = String.length str - prev_size in
     (C.project t, size_diff, existed)
 
   let remove s i =
@@ -837,7 +837,7 @@ module Make_indexed_subcontext (C : Raw_context.T) (I : INDEX) :
 
     type elt = I.t
 
-    let inited = Bytes.of_string "inited"
+    let inited = "inited"
 
     let mem s i = Raw_context.mem (pack s i) N.name
 
@@ -900,7 +900,7 @@ module Make_indexed_subcontext (C : Raw_context.T) (I : INDEX) :
       Raw_context.get (pack s i) N.name
       >>=? fun b ->
       let key () = Raw_context.absolute_key (pack s i) N.name in
-      Lwt.return (of_bytes ~key b)
+      Lwt.return (of_string ~key b)
 
     let find s i =
       Raw_context.find (pack s i) N.name
@@ -909,28 +909,28 @@ module Make_indexed_subcontext (C : Raw_context.T) (I : INDEX) :
           ok_none
       | Some b ->
           let key () = Raw_context.absolute_key (pack s i) N.name in
-          of_bytes ~key b >|? fun v -> Some v
+          of_string ~key b >|? fun v -> Some v
 
     let update s i v =
-      Raw_context.update (pack s i) N.name (to_bytes v)
+      Raw_context.update (pack s i) N.name (to_string v)
       >|=? fun c ->
       let (s, _) = unpack c in
       C.project s
 
     let init s i v =
-      Raw_context.init (pack s i) N.name (to_bytes v)
+      Raw_context.init (pack s i) N.name (to_string v)
       >|=? fun c ->
       let (s, _) = unpack c in
       C.project s
 
     let add s i v =
-      Raw_context.add (pack s i) N.name (to_bytes v)
+      Raw_context.add (pack s i) N.name (to_string v)
       >|= fun c ->
       let (s, _) = unpack c in
       C.project s
 
     let add_or_remove s i v =
-      Raw_context.add_or_remove (pack s i) N.name (Option.map to_bytes v)
+      Raw_context.add_or_remove (pack s i) N.name (Option.map to_string v)
       >|= fun c ->
       let (s, _) = unpack c in
       C.project s
@@ -1020,11 +1020,10 @@ module Make_indexed_subcontext (C : Raw_context.T) (I : INDEX) :
           (Storage_costs.read_access ~path_length ~read_bytes) )
 
     let consume_write_gas set c v =
-      let bytes = to_bytes v in
-      let len = Bytes.length bytes in
+      let str = to_string v in
+      let len = String.length str in
       Raw_context.consume_gas c (Storage_costs.write_access ~written_bytes:len)
-      >>?= fun c ->
-      set c len_name (encode_len_value bytes) >|=? fun c -> (c, bytes)
+      >>?= fun c -> set c len_name (encode_len_value str) >|=? fun c -> (c, str)
 
     let consume_remove_gas del c =
       Raw_context.consume_gas c (Storage_costs.write_access ~written_bytes:0)
@@ -1041,7 +1040,7 @@ module Make_indexed_subcontext (C : Raw_context.T) (I : INDEX) :
       Raw_context.get c data_name
       >>=? fun b ->
       let key () = Raw_context.absolute_key c data_name in
-      Lwt.return (of_bytes ~key b >|? fun v -> (Raw_context.project c, v))
+      Lwt.return (of_string ~key b >|? fun v -> (Raw_context.project c, v))
 
     let find s i =
       consume_mem_gas (pack s i)
@@ -1056,18 +1055,18 @@ module Make_indexed_subcontext (C : Raw_context.T) (I : INDEX) :
       existing_size (pack s i)
       >>=? fun (prev_size, _) ->
       consume_write_gas Raw_context.update (pack s i) v
-      >>=? fun (c, bytes) ->
-      Raw_context.update c data_name bytes
+      >>=? fun (c, str) ->
+      Raw_context.update c data_name str
       >|=? fun c ->
-      let size_diff = Bytes.length bytes - prev_size in
+      let size_diff = String.length str - prev_size in
       (Raw_context.project c, size_diff)
 
     let init s i v =
       consume_write_gas Raw_context.init (pack s i) v
-      >>=? fun (c, bytes) ->
-      Raw_context.init c data_name bytes
+      >>=? fun (c, str) ->
+      Raw_context.init c data_name str
       >|=? fun c ->
-      let size = Bytes.length bytes in
+      let size = String.length str in
       (Raw_context.project c, size)
 
     let add s i v =
@@ -1075,10 +1074,10 @@ module Make_indexed_subcontext (C : Raw_context.T) (I : INDEX) :
       existing_size (pack s i)
       >>=? fun (prev_size, existed) ->
       consume_write_gas add (pack s i) v
-      >>=? fun (c, bytes) ->
-      add c data_name bytes
+      >>=? fun (c, str) ->
+      add c data_name str
       >|=? fun c ->
-      let size_diff = Bytes.length bytes - prev_size in
+      let size_diff = String.length str - prev_size in
       (Raw_context.project c, size_diff, existed)
 
     let remove s i =
diff --git a/src/proto_alpha/lib_protocol/test/helpers/block.ml b/src/proto_alpha/lib_protocol/test/helpers/block.ml
index f52ac378eab104443213c147662c38d9106088c1..73ac6852f42d91bb9c3516f7003759da93670ad6 100644
--- a/src/proto_alpha/lib_protocol/test/helpers/block.ml
+++ b/src/proto_alpha/lib_protocol/test/helpers/block.ml
@@ -263,10 +263,11 @@ let initial_context ?(with_commitments = false) constants header
   let json = Default_parameters.json_of_parameters parameters in
   let proto_params =
     Data_encoding.Binary.to_bytes_exn Data_encoding.json json
+    |> Bytes.to_string
   in
   Tezos_protocol_environment.Context.(
     let empty = Memory_context.empty in
-    add empty ["version"] (Bytes.of_string "genesis")
+    add empty ["version"] "genesis"
     >>= fun ctxt -> add ctxt protocol_param_key proto_params)
   >>= fun ctxt ->
   Main.init ctxt header >|= Environment.wrap_error
@@ -290,10 +291,11 @@ let genesis_with_parameters parameters =
   let json = Default_parameters.json_of_parameters parameters in
   let proto_params =
     Data_encoding.Binary.to_bytes_exn Data_encoding.json json
+    |> Bytes.to_string
   in
   Tezos_protocol_environment.Context.(
     let empty = Memory_context.empty in
-    add empty ["version"] (Bytes.of_string "genesis")
+    add empty ["version"] "genesis"
     >>= fun ctxt -> add ctxt protocol_param_key proto_params)
   >>= fun ctxt ->
   Main.init ctxt shell >|= Environment.wrap_error
diff --git a/src/proto_alpha/lib_protocol/test/helpers/context.ml b/src/proto_alpha/lib_protocol/test/helpers/context.ml
index bad68594ada6c0d1546be65819e754769950fa31..01b42aef6a7a89cd736e833e3ae70f2ebccff448 100644
--- a/src/proto_alpha/lib_protocol/test/helpers/context.ml
+++ b/src/proto_alpha/lib_protocol/test/helpers/context.ml
@@ -198,12 +198,17 @@ module Vote = struct
   let get_participation_ema (b : Block.t) =
     Environment.Context.find b.context ["votes"; "participation_ema"]
     >|= function
-    | None -> assert false | Some bytes -> ok (TzEndian.get_int32 bytes 0)
+    | None ->
+        assert false
+    | Some str ->
+        let bytes = Bytes.unsafe_of_string str in
+        ok (TzEndian.get_int32 bytes 0)
 
   let set_participation_ema (b : Block.t) ema =
     let bytes = Bytes.make 4 '\000' in
     TzEndian.set_int32 bytes 0 ema ;
-    Environment.Context.add b.context ["votes"; "participation_ema"] bytes
+    let str = Bytes.unsafe_to_string bytes in
+    Environment.Context.add b.context ["votes"; "participation_ema"] str
     >|= fun context -> {b with context}
 end