diff --git a/src/action.ml b/src/action.ml
index 85ac8f53..6dc2f76f 100644
--- a/src/action.ml
+++ b/src/action.ml
@@ -660,7 +660,7 @@ module Promotion = struct
 
   let load_db () =
     if Sys.file_exists db_file then
-      Sexp.load ~fname:db_file ~mode:Many
+      Io.Sexp.load ~fname:db_file ~mode:Many
       |> List.map ~f:File.t
     else
       []
diff --git a/src/build_system.ml b/src/build_system.ml
index 6f9e39c5..57000e14 100644
--- a/src/build_system.ml
+++ b/src/build_system.ml
@@ -20,7 +20,7 @@ module Promoted_to_delete = struct
 
   let load () =
     if Sys.file_exists fn then
-      Sexp.load ~fname:fn ~mode:Many
+      Io.Sexp.load ~fname:fn ~mode:Many
       |> List.map ~f:Path.t
     else
       []
@@ -1126,7 +1126,7 @@ module Trace = struct
   let load () =
     let trace = Hashtbl.create 1024 in
     if Sys.file_exists file then begin
-      let sexp = Sexp.load ~fname:file ~mode:Single in
+      let sexp = Io.Sexp.load ~fname:file ~mode:Single in
       let bindings =
         let open Sexp.Of_sexp in
         list (pair Path.t (fun s -> Digest.from_hex (string s))) sexp
@@ -1207,7 +1207,7 @@ let update_universe t =
   let fname = Path.to_string universe_file in
   let n =
     if Sys.file_exists fname then
-      Sexp.Of_sexp.int (Sexp.load ~mode:Single ~fname) + 1
+      Sexp.Of_sexp.int (Io.Sexp.load ~mode:Single ~fname) + 1
     else
       0
   in
diff --git a/src/config.ml b/src/config.ml
index f877248e..9e5dc406 100644
--- a/src/config.ml
+++ b/src/config.ml
@@ -81,7 +81,7 @@ let t =
 let user_config_file = Filename.concat Xdg.config_dir "dune/config"
 
 let load_config_file ~fname =
-  t (Sexp.load_many_as_one ~fname)
+  t (Io.Sexp.load_many_as_one ~fname)
 
 let load_user_config_file () =
   if Sys.file_exists user_config_file then
diff --git a/src/installed_dune_file.ml b/src/installed_dune_file.ml
index 04480905..8dde3ae8 100644
--- a/src/installed_dune_file.ml
+++ b/src/installed_dune_file.ml
@@ -39,7 +39,7 @@ let of_sexp =
         (fun () l -> parse_sub_systems l)
     ]
 
-let load ~fname = of_sexp (Sexp.load ~mode:Single ~fname)
+let load ~fname = of_sexp (Io.Sexp.load ~mode:Single ~fname)
 
 let gen confs =
   let sexps =
diff --git a/src/jbuild.ml b/src/jbuild.ml
index d196bef7..f41befb1 100644
--- a/src/jbuild.ml
+++ b/src/jbuild.ml
@@ -1244,7 +1244,7 @@ module Stanzas = struct
               (Path.to_string_maybe_quoted file);
           if List.exists include_stack ~f:(fun (_, f) -> f = file) then
             raise (Include_loop (file, include_stack));
-          let sexps = Sexp.load ~fname:(Path.to_string file) ~mode:Many in
+          let sexps = Io.Sexp.load ~fname:(Path.to_string file) ~mode:Many in
           parse pkgs sexps ~default_version:Jbuild_version.V1 ~file ~include_stack)
       ; cstr "documentation" (Documentation.v1 pkgs @> nil)
           (fun d -> [Documentation d])
diff --git a/src/jbuild_load.ml b/src/jbuild_load.ml
index 6e33c073..018f776f 100644
--- a/src/jbuild_load.ml
+++ b/src/jbuild_load.ml
@@ -157,7 +157,7 @@ end
         die "@{<error>Error:@} %s failed to produce a valid jbuild file.\n\
              Did you forgot to call [Jbuild_plugin.V*.send]?"
           (Path.to_string file);
-      let sexps = Sexp.load ~fname:(Path.to_string generated_jbuild) ~mode:Many in
+      let sexps = Io.Sexp.load ~fname:(Path.to_string generated_jbuild) ~mode:Many in
       Fiber.return (dir, scope, Stanzas.parse scope sexps ~file:generated_jbuild
                                 |> filter_stanzas ~ignore_promoted_rules))
     >>| fun dynamic ->
@@ -184,14 +184,14 @@ module Sexp_io = struct
   let load_many_or_ocaml_script fname =
     Io.with_file_in fname ~f:(fun ic ->
       let state = Parser.create ~fname ~mode:Many in
-      let buf = Bytes.create buf_len in
+      let buf = Bytes.create Io.buf_len in
       let rec loop stack =
-        match input ic buf 0 buf_len with
+        match input ic buf 0 Io.buf_len with
         | 0 -> Parser.feed_eoi state stack
         | n -> loop (Parser.feed_subbytes state buf ~pos:0 ~len:n stack)
       in
       let rec loop0 stack i =
-        match input ic buf i (buf_len - i) with
+        match input ic buf i (Io.buf_len - i) with
         | 0 ->
           let stack = Parser.feed_subbytes state buf ~pos:0 ~len:i stack in
           Sexps (Parser.feed_eoi state stack)
diff --git a/src/stdune/io.ml b/src/stdune/io.ml
index fc39d707..74ba8cb9 100644
--- a/src/stdune/io.ml
+++ b/src/stdune/io.ml
@@ -76,3 +76,28 @@ let copy_file ~src ~dst =
 
 (* TODO: diml: improve this *)
 let compare_files fn1 fn2 = String.compare (read_file fn1) (read_file fn2)
+
+let buf_len = 65_536
+
+module Sexp = struct
+  open Sexp
+
+  let load ~fname ~mode =
+    with_file_in fname ~f:(fun ic ->
+      let state = Parser.create ~fname ~mode in
+      let buf = Bytes.create buf_len in
+      let rec loop stack =
+        match input ic buf 0 buf_len with
+        | 0 -> Parser.feed_eoi state stack
+        | n -> loop (Parser.feed_subbytes state buf ~pos:0 ~len:n stack)
+      in
+      loop Parser.Stack.empty)
+
+  let load_many_as_one ~fname =
+    match load ~fname ~mode:Many with
+    | [] -> Ast.List (Loc.in_file fname, [])
+    | x :: l ->
+      let last = Option.value (List.last l) ~default:x in
+      let loc = { (Ast.loc x) with stop = (Ast.loc last).stop } in
+      Ast.List (loc, x :: l)
+end
diff --git a/src/stdune/io.mli b/src/stdune/io.mli
index 9b621f36..cc1a604a 100644
--- a/src/stdune/io.mli
+++ b/src/stdune/io.mli
@@ -25,3 +25,12 @@ val copy_channels : in_channel -> out_channel -> unit
 val copy_file : src:string -> dst:string -> unit
 
 val read_all : in_channel -> string
+
+module Sexp : sig
+  val load : fname:string -> mode:'a Sexp.Parser.Mode.t -> 'a
+  val load_many_as_one : fname:string -> Sexp.Ast.t
+end
+
+(**/**)
+(* used in jbuild_load *)
+val buf_len : int
diff --git a/src/stdune/sexp.ml b/src/stdune/sexp.ml
index 7ace78e5..9e6272d9 100644
--- a/src/stdune/sexp.ml
+++ b/src/stdune/sexp.ml
@@ -1,26 +1,5 @@
 include Usexp
 
-let buf_len = 65_536
-
-let load ~fname ~mode =
-  Io.with_file_in fname ~f:(fun ic ->
-    let state = Parser.create ~fname ~mode in
-    let buf = Bytes.create buf_len in
-    let rec loop stack =
-      match input ic buf 0 buf_len with
-      | 0 -> Parser.feed_eoi state stack
-      | n -> loop (Parser.feed_subbytes state buf ~pos:0 ~len:n stack)
-    in
-    loop Parser.Stack.empty)
-
-let load_many_as_one ~fname =
-  match load ~fname ~mode:Many with
-  | [] -> Ast.List (Loc.in_file fname, [])
-  | x :: l ->
-    let last = Option.value (List.last l) ~default:x in
-    let loc = { (Ast.loc x) with stop = (Ast.loc last).stop } in
-    Ast.List (loc, x :: l)
-
 module type Combinators = sig
   type 'a t
   val unit       : unit                      t
diff --git a/src/stdune/sexp.mli b/src/stdune/sexp.mli
index d1a2d49c..f289664b 100644
--- a/src/stdune/sexp.mli
+++ b/src/stdune/sexp.mli
@@ -1,8 +1,5 @@
 include module type of struct include Usexp end with module Loc := Usexp.Loc
 
-val load : fname:string -> mode:'a Parser.Mode.t -> 'a
-val load_many_as_one : fname:string -> Ast.t
-
 module type Combinators = sig
   type 'a t
   val unit       : unit                      t
@@ -155,7 +152,3 @@ module Of_sexp : sig
 
   val enum : (string * 'a) list -> 'a t
 end
-
-(**/**)
-(* used in jbuild_load *)
-val buf_len : int
diff --git a/src/utils.ml b/src/utils.ml
index 8189cb65..257a27f9 100644
--- a/src/utils.ml
+++ b/src/utils.ml
@@ -204,7 +204,7 @@ module Cached_digest = struct
 
   let load () =
     if Sys.file_exists db_file then begin
-      let sexp = Sexp.load ~fname:db_file ~mode:Single in
+      let sexp = Io.Sexp.load ~fname:db_file ~mode:Single in
       let bindings =
         let open Sexp.Of_sexp in
         list
diff --git a/src/vfile_kind.ml b/src/vfile_kind.ml
index 3bc42f10..0c88e584 100644
--- a/src/vfile_kind.ml
+++ b/src/vfile_kind.ml
@@ -55,7 +55,7 @@ struct
   let to_string path x = To_sexp.t path x |> Sexp.to_string
 
   let load path =
-    Of_sexp.t path (Sexp.load ~fname:(Path.to_string path) ~mode:Single)
+    Of_sexp.t path (Io.Sexp.load ~fname:(Path.to_string path) ~mode:Single)
 end
 
 
diff --git a/src/workspace.ml b/src/workspace.ml
index 70448a68..338ea240 100644
--- a/src/workspace.ml
+++ b/src/workspace.ml
@@ -135,4 +135,4 @@ let t ?x sexps =
   ; contexts       = List.rev contexts
   }
 
-let load ?x fname = t ?x (Sexp.load ~fname ~mode:Many)
+let load ?x fname = t ?x (Io.Sexp.load ~fname ~mode:Many)