diff --git a/src/dune_rules/exe.ml b/src/dune_rules/exe.ml
index b44d1380e9d..07567687cf9 100644
--- a/src/dune_rules/exe.ml
+++ b/src/dune_rules/exe.ml
@@ -258,6 +258,7 @@ let link_js
       ~promote
       ~link_time_code_gen
       ~jsoo_mode
+      ~standalone_runtime
       cctx
   =
   let in_context =
@@ -285,6 +286,7 @@ let link_js
     ~link_time_code_gen
     ~linkall
     ~jsoo_mode
+    ~standalone_runtime
 ;;
 
 type dep_graphs = { for_exes : Module.t list Action_builder.t list }
@@ -306,6 +308,39 @@ let link_many
   in
   let modules = Compilation_context.modules cctx in
   let* link_time_code_gen = Link_time_code_gen.handle_special_libs cctx in
+  (* Build shared jsoo standalone runtimes (one per mode) *)
+  let* (shared_runtimes : Jsoo_rules.standalone_runtime option Js_of_ocaml.Mode.Pair.t) =
+    let in_context_for jsoo_mode =
+      Compilation_context.js_of_ocaml cctx
+      |> Js_of_ocaml.Mode.Pair.select ~mode:jsoo_mode
+      |> Option.value ~default:Js_of_ocaml.In_context.default
+    in
+    let loc =
+      match programs with
+      | p :: _ -> p.Program.loc
+      | [] -> Loc.none
+    in
+    let+ js =
+      if List.exists linkages ~f:(Linkage.is_jsoo ~mode:JS)
+      then
+        Jsoo_rules.build_standalone_runtime
+          cctx
+          ~loc
+          ~in_context:(in_context_for JS)
+          ~jsoo_mode:JS
+      else Memo.return None
+    and+ wasm =
+      if List.exists linkages ~f:(Linkage.is_jsoo ~mode:Wasm)
+      then
+        Jsoo_rules.build_standalone_runtime
+          cctx
+          ~loc
+          ~in_context:(in_context_for Wasm)
+          ~jsoo_mode:Wasm
+      else Memo.return None
+    in
+    { Js_of_ocaml.Mode.Pair.js; wasm }
+  in
   let+ for_exes =
     Memo.parallel_map programs ~f:(fun { Program.name; main_module_name; loc } ->
       let top_sorted_modules =
@@ -338,6 +373,9 @@ let link_many
           match linkage.Linkage.mode with
           | Jsoo jsoo_mode ->
             let obj_dir = Compilation_context.obj_dir cctx in
+            let standalone_runtime =
+              Js_of_ocaml.Mode.Pair.select ~mode:jsoo_mode shared_runtimes
+            in
             link_js
               ~loc
               ~name
@@ -348,6 +386,7 @@ let link_many
               cctx
               ~link_time_code_gen
               ~jsoo_mode
+              ~standalone_runtime
           | Ocaml linkage_mode ->
             let* link_time_code_gen =
               match Linkage.is_plugin linkage with
diff --git a/src/dune_rules/gen_rules.ml b/src/dune_rules/gen_rules.ml
index af9cfe33d5e..5e73de3e249 100644
--- a/src/dune_rules/gen_rules.ml
+++ b/src/dune_rules/gen_rules.ml
@@ -628,7 +628,8 @@ let gen_rules ctx sctx ~dir components : Gen_rules.result Memo.t =
     has_rules
       ~dir
       (match rest with
-       | [] -> Subdir_set.all
+       | [] | [ _ ] -> Subdir_set.all
+       | [ _; ".runtime" ] -> Subdir_set.all
        | _ -> Subdir_set.empty)
       (fun () ->
          (* XXX the use of the super context is dubious here. We're using it to
diff --git a/src/dune_rules/jsoo/jsoo_rules.ml b/src/dune_rules/jsoo/jsoo_rules.ml
index 64e459c489c..19d2d60c588 100644
--- a/src/dune_rules/jsoo/jsoo_rules.ml
+++ b/src/dune_rules/jsoo/jsoo_rules.ml
@@ -344,6 +344,12 @@ let js_of_ocaml_flags t ~dir ~mode (spec : Js_of_ocaml.Flags.Spec.t) =
     ~eval:(Expander.expand_and_eval_set expander)
 ;;
 
+let resolve_config sctx ~dir ~mode flags =
+  js_of_ocaml_flags sctx ~dir ~mode flags
+  |> Action_builder.bind ~f:(fun (x : _ Js_of_ocaml.Flags.t) -> x.compile)
+  |> Action_builder.map ~f:Config.of_flags
+;;
+
 let js_of_ocaml_rule
       sctx
       ~(mode : Js_of_ocaml.Mode.t)
@@ -421,14 +427,104 @@ let jsoo_runtime_files ~(mode : Js_of_ocaml.Mode.t) libs =
       (Lib.info t))
 ;;
 
+module Runtime_key : sig
+  type encoded = Digest.t
+
+  module Decoded : sig
+    type t = private
+      { mode : Js_of_ocaml.Mode.t
+      ; lib_names : Lib_name.t list
+      ; project_root : Path.Source.t option
+      }
+
+    val of_libs : mode:Js_of_ocaml.Mode.t -> Lib.t list -> t
+  end
+
+  val encode : Decoded.t -> encoded
+  val decode : encoded -> Decoded.t
+end = struct
+  type encoded = Digest.t
+
+  module Decoded = struct
+    type t =
+      { mode : Js_of_ocaml.Mode.t
+      ; lib_names : Lib_name.t list
+      ; project_root : Path.Source.t option
+      }
+
+    let equal x y =
+      Js_of_ocaml.Mode.equal x.mode y.mode
+      && List.equal Lib_name.equal x.lib_names y.lib_names
+      && Option.equal Path.Source.equal x.project_root y.project_root
+    ;;
+
+    let to_string { mode; lib_names; project_root } =
+      let s =
+        sprintf
+          "%s runtime for %s"
+          (Js_of_ocaml.Mode.select ~mode ~js:"js" ~wasm:"wasm")
+          (String.enumerate_and (List.map lib_names ~f:Lib_name.to_string))
+      in
+      match project_root with
+      | None -> s
+      | Some dir ->
+        sprintf "%s (in project: %s)" s (Path.Source.to_string_maybe_quoted dir)
+    ;;
+
+    let of_libs ~mode libs =
+      let libs_with_runtime =
+        List.filter libs ~f:(fun lib ->
+          not (List.is_empty (jsoo_runtime_files ~mode [ lib ])))
+      in
+      let lib_names =
+        List.sort libs_with_runtime ~compare:(fun a b ->
+          Lib_name.compare (Lib.name a) (Lib.name b))
+        |> List.map ~f:Lib.name
+      in
+      let project_root = Lib.L.project_root libs_with_runtime in
+      { mode; lib_names; project_root }
+    ;;
+  end
+
+  let reverse_table : (Digest.t, Decoded.t) Table.t = Table.create (module Digest) 128
+
+  let encode ({ Decoded.mode; lib_names; project_root } as x) =
+    let y = Digest.generic (mode, lib_names, project_root) in
+    match Table.find reverse_table y with
+    | None ->
+      Table.set reverse_table y x;
+      y
+    | Some x' ->
+      if Decoded.equal x x'
+      then y
+      else
+        User_error.raise
+          [ Pp.textf "Hash collision between jsoo standalone runtimes:"
+          ; Pp.textf "- cache : %s" (Decoded.to_string x')
+          ; Pp.textf "- fetch : %s" (Decoded.to_string x)
+          ]
+  ;;
+
+  let decode y =
+    match Table.find reverse_table y with
+    | Some x -> x
+    | None ->
+      User_error.raise
+        [ Pp.textf
+            "I don't know what jsoo runtime set %s correspond to."
+            (Digest.to_string y)
+        ]
+  ;;
+end
+
+type standalone_runtime =
+  | Shared of Digest.t
+  | Per_stanza of Path.Build.t
+
 let standalone_runtime_rule ~mode cc ~runtime_files ~target ~flags ~sourcemap =
   let dir = Compilation_context.dir cc in
   let sctx = Compilation_context.super_context cc in
-  let config =
-    js_of_ocaml_flags sctx ~dir ~mode flags
-    |> Action_builder.bind ~f:(fun (x : _ Js_of_ocaml.Flags.t) -> x.compile)
-    |> Action_builder.map ~f:Config.of_flags
-  in
+  let config = resolve_config sctx ~dir ~mode flags in
   let libs = Compilation_context.requires_link cc in
   let spec =
     Command.Args.S
@@ -547,7 +643,7 @@ let cmo_js_of_module ~mode m =
 let link_rule
       ~mode
       cc
-      ~runtime
+      ~runtime_dep
       ~target
       ~directory_targets
       ~obj_dir
@@ -562,10 +658,7 @@ let link_rule
   let ctx = Super_context.context sctx |> Context.build_context in
   let get_all =
     let open Action_builder.O in
-    let+ config =
-      js_of_ocaml_flags sctx ~dir ~mode flags
-      |> Action_builder.bind ~f:(fun (x : _ Js_of_ocaml.Flags.t) -> x.compile)
-      |> Action_builder.map ~f:Config.of_flags
+    let+ config = resolve_config sctx ~dir ~mode flags
     and+ cm = cm
     and+ linkall = linkall
     and+ libs = Resolve.Memo.read (Compilation_context.requires_link cc)
@@ -620,7 +713,7 @@ let link_rule
            | None, _ | _, false -> [])
       ]
   in
-  let spec = Command.Args.S [ Dep (Path.build runtime); Dyn get_all ] in
+  let spec = Command.Args.S [ Dyn runtime_dep; Dyn get_all ] in
   js_of_ocaml_rule
     sctx
     ~mode
@@ -700,10 +793,7 @@ let build_cm
     and+ config =
       match config_opt with
       | Some config -> Action_builder.return config
-      | None ->
-        js_of_ocaml_flags sctx ~dir ~mode in_context.flags
-        |> Action_builder.bind ~f:(fun (x : _ Js_of_ocaml.Flags.t) -> x.compile)
-        |> Action_builder.map ~f:Config.of_flags
+      | None -> resolve_config sctx ~dir ~mode in_context.flags
     in
     let deps = List.filter deps ~f:(fun m -> Module.has m ~ml_kind:Impl) in
     (Path.build (in_build_dir ctx ~config [ "stdlib"; with_js_ext ~mode "stdlib.cma" ])
@@ -725,9 +815,58 @@ let build_cm
 
 let for_ = Compilation_mode.Ocaml
 
+let setup_shared_runtime_rule sctx s_config s_digest =
+  let config = Config.of_string s_config in
+  let ctx = Super_context.context sctx in
+  let build_context = Context.build_context ctx in
+  match Digest.from_hex s_digest with
+  | None -> User_error.raise [ Pp.textf "invalid jsoo runtime key: %s" s_digest ]
+  | Some digest ->
+    let { Runtime_key.Decoded.mode; lib_names; project_root } =
+      Runtime_key.decode digest
+    in
+    let* scope =
+      let dir =
+        match project_root with
+        | None -> Context.build_dir ctx
+        | Some dir -> Path.Build.append_source build_context.build_dir dir
+      in
+      Scope.DB.find_by_dir dir
+    in
+    let* libs =
+      let lib_db = Scope.libs scope in
+      Memo.parallel_map lib_names ~f:(fun name ->
+        Lib.DB.resolve lib_db (Loc.none, name) |> Resolve.Memo.read_memo)
+    in
+    let runtime_files = jsoo_runtime_files ~mode libs in
+    let dir = in_build_dir build_context ~config [ ".runtime"; s_digest ] in
+    let target =
+      in_build_dir
+        build_context
+        ~config
+        [ ".runtime"
+        ; s_digest
+        ; "runtime" ^ Filename.Extension.to_string (Js_of_ocaml.Ext.runtime ~mode)
+        ]
+    in
+    js_of_ocaml_rule
+      sctx
+      ~mode
+      ~sub_command:Build_runtime
+      ~dir
+      ~flags:Js_of_ocaml.In_context.default.flags
+      ~target
+      ~spec:(Command.Args.Deps runtime_files)
+      ~config:(Some (Action_builder.return config))
+      ~sourcemap:Inline
+      ~directory_targets:[]
+    |> Super_context.add_rule sctx ~dir
+;;
+
 let setup_separate_compilation_rules sctx components =
   match components with
-  | _ :: _ :: _ :: _ | [] | [ _ ] -> Memo.return ()
+  | [ s_config; ".runtime"; s_digest ] -> setup_shared_runtime_rule sctx s_config s_digest
+  | [] | [ _ ] | [ _; ".runtime" ] -> Memo.return ()
   | [ s_config; s_pkg ] ->
     let config = Config.of_string s_config in
     let pkg = Lib_name.parse_string_exn (Loc.none, s_pkg) in
@@ -801,6 +940,7 @@ let setup_separate_compilation_rules sctx components =
              ~sourcemap:Js_of_ocaml.Sourcemap.Inline
              ~shapes
            |> Super_context.add_rule sctx ~dir)))
+  | _ -> Memo.return ()
 ;;
 
 let js_of_ocaml_compilation_mode t ~dir ~mode =
@@ -867,6 +1007,55 @@ let jsoo_is_whole_program t ~dir ~in_context =
   { Js_of_ocaml.Mode.Pair.js = is_whole_program js; wasm = is_whole_program wasm }
 ;;
 
+let build_standalone_runtime cc ~loc ~in_context ~jsoo_mode:mode =
+  let sctx = Compilation_context.super_context cc in
+  let dir = Compilation_context.dir cc in
+  let { Js_of_ocaml.In_context.javascript_files
+      ; wasm_files
+      ; flags
+      ; compilation_mode
+      ; sourcemap = _
+      ; enabled_if = _
+      }
+    =
+    in_context
+  in
+  let* cmode =
+    match compilation_mode with
+    | None -> js_of_ocaml_compilation_mode sctx ~dir ~mode
+    | Some x -> Memo.return x
+  in
+  match (cmode : Js_of_ocaml.Compilation_mode.t) with
+  | Whole_program -> Memo.return None
+  | Separate_compilation ->
+    assert (Js_of_ocaml.Mode.select ~mode ~js:(wasm_files = []) ~wasm:true);
+    let runtime_files = javascript_files @ wasm_files in
+    let* eligible =
+      if List.is_empty runtime_files
+      then
+        Resolve.Memo.peek (Compilation_context.requires_link cc)
+        >>| function
+        | Ok libs -> Some (Runtime_key.encode (Runtime_key.Decoded.of_libs ~mode libs))
+        | Error () -> None
+      else Memo.return None
+    in
+    (match eligible with
+     | Some digest -> Memo.return (Some (Shared digest))
+     | None ->
+       let obj_dir = Compilation_context.obj_dir cc in
+       let target =
+         in_obj_dir
+           ~obj_dir
+           ~config:None
+           [ "runtime" ^ Filename.Extension.to_string (Js_of_ocaml.Ext.runtime ~mode) ]
+       in
+       let+ () =
+         standalone_runtime_rule ~mode cc ~runtime_files ~target ~flags ~sourcemap:Inline
+         |> Super_context.add_rule ~loc sctx ~dir
+       in
+       Some (Per_stanza target))
+;;
+
 let build_exe
       cc
       ~loc
@@ -878,6 +1067,7 @@ let build_exe
       ~linkall
       ~link_time_code_gen
       ~jsoo_mode:mode
+      ~standalone_runtime
   =
   let sctx = Compilation_context.super_context cc in
   let dir = Compilation_context.dir cc in
@@ -887,14 +1077,6 @@ let build_exe
     in_context
   in
   let target = Path.Build.set_extension src ~ext:(Js_of_ocaml.Ext.exe ~mode) in
-  let standalone_runtime =
-    in_obj_dir
-      ~obj_dir
-      ~config:None
-      [ Path.Build.basename
-          (Path.Build.set_extension src ~ext:(Js_of_ocaml.Ext.runtime ~mode))
-      ]
-  in
   let* rule_mode : Rule.Mode.t =
     let* expander = Super_context.expander sctx ~dir in
     let rule_mode =
@@ -922,20 +1104,47 @@ let build_exe
   in
   match (cmode : Js_of_ocaml.Compilation_mode.t) with
   | Separate_compilation ->
+    let runtime_dep, per_exe_runtime_target =
+      match standalone_runtime with
+      | Some (Shared digest) ->
+        let ctx = Super_context.context sctx |> Context.build_context in
+        ( (let open Action_builder.O in
+           let+ config = resolve_config sctx ~dir ~mode flags in
+           Command.Args.Dep
+             (Path.build
+                (in_build_dir
+                   ctx
+                   ~config
+                   [ ".runtime"
+                   ; Digest.to_string digest
+                   ; "runtime"
+                     ^ Filename.Extension.to_string (Js_of_ocaml.Ext.runtime ~mode)
+                   ])))
+        , None )
+      | Some (Per_stanza path) ->
+        Action_builder.return (Command.Args.Dep (Path.build path)), None
+      | None ->
+        let path =
+          in_obj_dir
+            ~obj_dir
+            ~config:None
+            [ Path.Build.basename
+                (Path.Build.set_extension src ~ext:(Js_of_ocaml.Ext.runtime ~mode))
+            ]
+        in
+        Action_builder.return (Command.Args.Dep (Path.build path)), Some path
+    in
     let+ () =
-      standalone_runtime_rule
-        ~mode
-        cc
-        ~runtime_files
-        ~target:standalone_runtime
-        ~flags
-        ~sourcemap:Inline
-      |> Super_context.add_rule ~loc sctx ~dir
+      match per_exe_runtime_target with
+      | Some target ->
+        standalone_runtime_rule ~mode cc ~runtime_files ~target ~flags ~sourcemap:Inline
+        |> Super_context.add_rule ~loc sctx ~dir
+      | None -> Memo.return ()
     and+ () =
       link_rule
         ~mode
         cc
-        ~runtime:standalone_runtime
+        ~runtime_dep
         ~target
         ~directory_targets
         ~obj_dir
diff --git a/src/dune_rules/jsoo/jsoo_rules.mli b/src/dune_rules/jsoo/jsoo_rules.mli
index 7110f00bd44..8e9fc51a07d 100644
--- a/src/dune_rules/jsoo/jsoo_rules.mli
+++ b/src/dune_rules/jsoo/jsoo_rules.mli
@@ -26,6 +26,17 @@ val build_cm
   -> config:Config.t option
   -> Action.Full.t Action_builder.With_targets.t
 
+type standalone_runtime =
+  | Shared of Digest.t
+  | Per_stanza of Path.Build.t
+
+val build_standalone_runtime
+  :  Compilation_context.t
+  -> loc:Loc.t
+  -> in_context:Js_of_ocaml.In_context.t
+  -> jsoo_mode:Js_of_ocaml.Mode.t
+  -> standalone_runtime option Memo.t
+
 val build_exe
   :  Compilation_context.t
   -> loc:Loc.t
@@ -37,6 +48,7 @@ val build_exe
   -> linkall:bool Action_builder.t
   -> link_time_code_gen:Link_time_code_gen_type.t Resolve.t
   -> jsoo_mode:Js_of_ocaml.Mode.t
+  -> standalone_runtime:standalone_runtime option
   -> unit Memo.t
 
 val setup_separate_compilation_rules : Super_context.t -> string list -> unit Memo.t
diff --git a/test/blackbox-tests/test-cases/jsoo/build-info.t/run.t b/test/blackbox-tests/test-cases/jsoo/build-info.t/run.t
index b2f9564d9e7..d921079a40c 100644
--- a/test/blackbox-tests/test-cases/jsoo/build-info.t/run.t
+++ b/test/blackbox-tests/test-cases/jsoo/build-info.t/run.t
@@ -6,12 +6,13 @@ Jsoo and build-info
   Consider passing '-g' option to ocamlc.
   $ node _build/default/src/main.bc.js
   unknown
-  $ dune install --prefix _install --display short
-  Installing _install/lib/main/META
-  Installing _install/lib/main/dune-package
-  Installing _install/lib/main/opam
-  Installing _install/bin/main
-  Installing _install/bin/main.bc.js
+  $ dune install --prefix _install
+  $ find _install -type f | sort
+  _install/bin/main
+  _install/bin/main.bc.js
+  _install/lib/main/META
+  _install/lib/main/dune-package
+  _install/lib/main/opam
   $ node _install/bin/main.bc.js
   unknown
   $ git init -q
@@ -26,18 +27,14 @@ Jsoo and build-info
   Consider passing '-g' option to ocamlc.
   $ node _build/default/src/main.bc.js
   unknown
-  $ dune install --prefix _install --display short
-  Deleting _install/lib/main/META
-  Installing _install/lib/main/META
-  Deleting _install/lib/main/dune-package
-  Installing _install/lib/main/dune-package
-  Deleting _install/lib/main/opam
-  Installing _install/lib/main/opam
-  Deleting _install/bin/main
-  Installing _install/bin/main
-  Deleting _install/bin/main.bc.js
-  Installing _install/bin/main.bc.js
-  Installing _install/doc/main/README
+  $ dune install --prefix _install
+  $ find _install -type f | sort
+  _install/bin/main
+  _install/bin/main.bc.js
+  _install/doc/main/README
+  _install/lib/main/META
+  _install/lib/main/dune-package
+  _install/lib/main/opam
   $ node _install/bin/main.bc.js
   v1-1-xxxxx-dirty
   $ echo "(name main)" >> dune-project
@@ -47,18 +44,13 @@ Jsoo and build-info
   Consider passing '-g' option to ocamlc.
   $ node _build/default/src/main.bc.js
   0.2.0
-  $ dune install --prefix _install --display short
-  Deleting _install/lib/main/META
-  Installing _install/lib/main/META
-  Deleting _install/lib/main/dune-package
-  Installing _install/lib/main/dune-package
-  Deleting _install/lib/main/opam
-  Installing _install/lib/main/opam
-  Deleting _install/bin/main
-  Installing _install/bin/main
-  Deleting _install/bin/main.bc.js
-  Installing _install/bin/main.bc.js
-  Deleting _install/doc/main/README
-  Installing _install/doc/main/README
+  $ dune install --prefix _install
+  $ find _install -type f | sort
+  _install/bin/main
+  _install/bin/main.bc.js
+  _install/doc/main/README
+  _install/lib/main/META
+  _install/lib/main/dune-package
+  _install/lib/main/opam
   $ node _build/default/src/main.bc.js
   0.2.0
diff --git a/test/blackbox-tests/test-cases/jsoo/explicit-js-mode-anon.t/run.t b/test/blackbox-tests/test-cases/jsoo/explicit-js-mode-anon.t/run.t
index d1722ce6cbe..fa61cc6d6c3 100644
--- a/test/blackbox-tests/test-cases/jsoo/explicit-js-mode-anon.t/run.t
+++ b/test/blackbox-tests/test-cases/jsoo/explicit-js-mode-anon.t/run.t
@@ -1,5 +1,8 @@
 Anonymous projects have explicit_js_mode enabled
 
   $ echo '(lang dune 2.8)' > dune-project
-  $ dune build --display short @all 2>&1 | grep -F .js
-  [1]
+  $ dune build @all
+  $ dune trace cat | jq -r 'include "dune";
+  >   processes
+  > | select(.args.prog | test("js_of_ocaml$"))
+  > | .args | targets | .[] | sub("^_build/[^/]+/"; "")'
diff --git a/test/blackbox-tests/test-cases/jsoo/explicit-js-mode-specified.t/run.t b/test/blackbox-tests/test-cases/jsoo/explicit-js-mode-specified.t/run.t
index 7c4f3be0c18..6d5d71cbe8e 100644
--- a/test/blackbox-tests/test-cases/jsoo/explicit-js-mode-specified.t/run.t
+++ b/test/blackbox-tests/test-cases/jsoo/explicit-js-mode-specified.t/run.t
@@ -22,16 +22,19 @@ Check that js targets are attached to @all, but not for tests that do not
 specify js mode (#1940).
 
   $ dune clean
-  $ dune build --display short @@all 2>&1 | grep js_of_ocaml
-   js_of_ocaml .b.eobjs/jsoo/b.bc.runtime.js
-   js_of_ocaml .e.eobjs/jsoo/e.bc.runtime.js
-   js_of_ocaml .js/default/stdlib/stdlib.cma.js
-   js_of_ocaml .js/default/stdlib/std_exit.cmo.js
-   js_of_ocaml .b.eobjs/jsoo/b.cmo.js
-   js_of_ocaml b.bc.js
-   js_of_ocaml .foo.objs/jsoo/default/foo.cma.js
-   js_of_ocaml .e.eobjs/jsoo/e.cmo.js
-   js_of_ocaml e.bc.js
+  $ dune build @@all
+  $ dune trace cat | jq -r 'include "dune";
+  >   processes
+  > | select(.args.prog | test("js_of_ocaml$"))
+  > | .args | targets | .[] | sub("^_build/[^/]+/"; "")' | sort
+  .b.eobjs/jsoo/b.cmo.js
+  .e.eobjs/jsoo/e.cmo.js
+  .foo.objs/jsoo/default/foo.cma.js
+  .js/default/.runtime/69326c30fc4a6ffc800b0a8e0b822993/runtime.bc.runtime.js
+  .js/default/stdlib/std_exit.cmo.js
+  .js/default/stdlib/stdlib.cma.js
+  b.bc.js
+  e.bc.js
 
 Check that building a JS-enabled executable that depends on a library works.
 
diff --git a/test/blackbox-tests/test-cases/jsoo/jsoo-config.t/run.t b/test/blackbox-tests/test-cases/jsoo/jsoo-config.t/run.t
index 95d85a917c1..c38c2571af6 100644
--- a/test/blackbox-tests/test-cases/jsoo/jsoo-config.t/run.t
+++ b/test/blackbox-tests/test-cases/jsoo/jsoo-config.t/run.t
@@ -1,6 +1,32 @@
 tests js_of_ocaml conigs
 
-  $ dune build bin/bin1.bc.js bin/bin2.bc.js bin/bin3.bc.js
+  $ dune build bin/bin1.bc.js bin/bin2.bc.js bin/bin3.bc.js --display short
+   js_of_ocaml .js/use-js-string/.runtime/69326c30fc4a6ffc800b0a8e0b822993/runtime.bc.runtime.js
+   js_of_ocaml .js/use-js-string/stdlib/std_exit.cmo.js
+   js_of_ocaml .js/use-js-string/stdlib/stdlib.cma.js
+        ocamlc lib/.library1.objs/byte/library1.{cmi,cmo,cmt}
+   js_of_ocaml .js/!use-js-string/.runtime/69326c30fc4a6ffc800b0a8e0b822993/runtime.bc.runtime.js
+   js_of_ocaml .js/!use-js-string/stdlib/std_exit.cmo.js
+   js_of_ocaml .js/!use-js-string/stdlib/stdlib.cma.js
+   js_of_ocaml .js/default/.runtime/69326c30fc4a6ffc800b0a8e0b822993/runtime.bc.runtime.js
+   js_of_ocaml .js/default/stdlib/std_exit.cmo.js
+   js_of_ocaml .js/default/stdlib/stdlib.cma.js
+        ocamlc bin/.bin1.eobjs/byte/dune__exe__Bin1.{cmi,cmti}
+        ocamlc lib/library1.cma
+        ocamlc bin/.bin2.eobjs/byte/dune__exe__Bin2.{cmi,cmti}
+        ocamlc bin/.bin3.eobjs/byte/dune__exe__Bin3.{cmi,cmti}
+        ocamlc bin/.bin1.eobjs/byte/dune__exe__Bin1.{cmo,cmt}
+   js_of_ocaml lib/.library1.objs/jsoo/use-js-string/library1.cma.js
+   js_of_ocaml lib/.library1.objs/jsoo/!use-js-string/library1.cma.js
+   js_of_ocaml lib/.library1.objs/jsoo/default/library1.cma.js
+        ocamlc bin/.bin2.eobjs/byte/dune__exe__Bin2.{cmo,cmt}
+        ocamlc bin/.bin3.eobjs/byte/dune__exe__Bin3.{cmo,cmt}
+   js_of_ocaml bin/.bin1.eobjs/jsoo/dune__exe__Bin1.cmo.js
+   js_of_ocaml bin/.bin2.eobjs/jsoo/dune__exe__Bin2.cmo.js
+   js_of_ocaml bin/.bin3.eobjs/jsoo/dune__exe__Bin3.cmo.js
+   js_of_ocaml bin/bin1.bc.js
+   js_of_ocaml bin/bin2.bc.js
+   js_of_ocaml bin/bin3.bc.js
   $ node _build/default/bin/bin1.bc.js
   Hello bin1
   Hi library1
diff --git a/test/blackbox-tests/test-cases/jsoo/no-check-prim.t/run.t b/test/blackbox-tests/test-cases/jsoo/no-check-prim.t/run.t
index 450c1bdd550..6ac1e87c3e4 100644
--- a/test/blackbox-tests/test-cases/jsoo/no-check-prim.t/run.t
+++ b/test/blackbox-tests/test-cases/jsoo/no-check-prim.t/run.t
@@ -1,31 +1,19 @@
 Compilation using jsoo
 
-  $ dune build --display short bin/technologic.bc.js @install  2>&1 | \
-  > sed s,^\ *$(ocamlc -config-var c_compiler),\ \ C_COMPILER,g
-      ocamldep bin/.technologic.eobjs/technologic.impl.d
-      ocamldep lib/.x.objs/x.impl.d
-        ocamlc lib/.x.objs/byte/x__.{cmi,cmo,cmt}
-      ocamldep lib/.x.objs/x__Y.impl.d
-   js_of_ocaml bin/.technologic.eobjs/jsoo/technologic.bc.runtime.js
-      ocamldep bin/.technologic.eobjs/z.impl.d
-      ocamlopt lib/.x.objs/native/x__.{cmx,o}
-        ocamlc lib/.x.objs/byte/x__Y.{cmi,cmo,cmt}
-   js_of_ocaml .js/default/stdlib/stdlib.cma.js
-   js_of_ocaml .js/default/stdlib/std_exit.cmo.js
-      ocamlopt lib/.x.objs/native/x__Y.{cmx,o}
-        ocamlc lib/.x.objs/byte/x.{cmi,cmo,cmt}
-   js_of_ocaml .js/default/js_of_ocaml-compiler.runtime/jsoo_runtime.cma.js
-      ocamlopt lib/.x.objs/native/x.{cmx,o}
-        ocamlc bin/.technologic.eobjs/byte/z.{cmi,cmo,cmt}
-        ocamlc lib/x.cma
-   js_of_ocaml .js/default/js_of_ocaml/js_of_ocaml.cma.js
-      ocamlopt lib/x.{a,cmxa}
-        ocamlc bin/.technologic.eobjs/byte/technologic.{cmi,cmo,cmt}
-   js_of_ocaml lib/.x.objs/jsoo/default/x.cma.js
-      ocamlopt lib/x.cmxs
-   js_of_ocaml bin/.technologic.eobjs/jsoo/z.cmo.js
-   js_of_ocaml bin/.technologic.eobjs/jsoo/technologic.cmo.js
-   js_of_ocaml bin/technologic.bc.js
+  $ dune build bin/technologic.bc.js @install
+  $ dune trace cat | jq -r 'include "dune";
+  >   processes
+  > | select(.args.prog | test("js_of_ocaml$"))
+  > | .args | targets | .[] | sub("^_build/[^/]+/"; "")' | sort
+  .js/default/js_of_ocaml-compiler.runtime/jsoo_runtime.cma.js
+  .js/default/js_of_ocaml/js_of_ocaml.cma.js
+  .js/default/stdlib/std_exit.cmo.js
+  .js/default/stdlib/stdlib.cma.js
+  bin/.technologic.eobjs/jsoo/runtime.bc.runtime.js
+  bin/.technologic.eobjs/jsoo/technologic.cmo.js
+  bin/.technologic.eobjs/jsoo/z.cmo.js
+  bin/technologic.bc.js
+  lib/.x.objs/jsoo/default/x.cma.js
   $ node ./_build/default/bin/technologic.bc.js
   buy it
   use it
diff --git a/test/blackbox-tests/test-cases/wasmoo/build-info.t/run.t b/test/blackbox-tests/test-cases/wasmoo/build-info.t/run.t
index 153c78552a2..4d3abed26da 100644
--- a/test/blackbox-tests/test-cases/wasmoo/build-info.t/run.t
+++ b/test/blackbox-tests/test-cases/wasmoo/build-info.t/run.t
@@ -6,25 +6,26 @@ Jsoo and build-info
   Warning: Consider passing '-g' option to ocamlc.
   $ node _build/default/src/main.bc.wasm.js
   unknown
-  $ dune install --prefix _install --display short 2>&1 | sed 's/-[a-f0-9]*[.]wasm/.wasm/'
-  Installing _install/lib/main/META
-  Installing _install/lib/main/dune-package
-  Installing _install/lib/main/opam
-  Installing _install/bin/main
-  Installing _install/bin/main.bc.wasm.assets/build_info.wasm
-  Installing _install/bin/main.bc.wasm.assets/build_info.wasm.map
-  Installing _install/bin/main.bc.wasm.assets/build_info__Build_info_data.wasm
-  Installing _install/bin/main.bc.wasm.assets/build_info__Build_info_data.wasm.map
-  Installing _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm
-  Installing _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm.map
-  Installing _install/bin/main.bc.wasm.assets/prelude.wasm
-  Installing _install/bin/main.bc.wasm.assets/runtime.wasm
-  Installing _install/bin/main.bc.wasm.assets/start.wasm
-  Installing _install/bin/main.bc.wasm.assets/std_exit.wasm
-  Installing _install/bin/main.bc.wasm.assets/std_exit.wasm.map
-  Installing _install/bin/main.bc.wasm.assets/stdlib.wasm
-  Installing _install/bin/main.bc.wasm.assets/stdlib.wasm.map
-  Installing _install/bin/main.bc.wasm.js
+  $ dune install --prefix _install
+  $ find _install -type f | sed 's/-[a-f0-9]*[.]wasm/.wasm/' | sort -u
+  _install/bin/main
+  _install/bin/main.bc.wasm.assets/build_info.wasm
+  _install/bin/main.bc.wasm.assets/build_info.wasm.map
+  _install/bin/main.bc.wasm.assets/build_info__Build_info_data.wasm
+  _install/bin/main.bc.wasm.assets/build_info__Build_info_data.wasm.map
+  _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm
+  _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm.map
+  _install/bin/main.bc.wasm.assets/prelude.wasm
+  _install/bin/main.bc.wasm.assets/runtime.wasm
+  _install/bin/main.bc.wasm.assets/start.wasm
+  _install/bin/main.bc.wasm.assets/std_exit.wasm
+  _install/bin/main.bc.wasm.assets/std_exit.wasm.map
+  _install/bin/main.bc.wasm.assets/stdlib.wasm
+  _install/bin/main.bc.wasm.assets/stdlib.wasm.map
+  _install/bin/main.bc.wasm.js
+  _install/lib/main/META
+  _install/lib/main/dune-package
+  _install/lib/main/opam
   $ node _install/bin/main.bc.wasm.js
   unknown
   $ git init -q
@@ -39,42 +40,27 @@ Jsoo and build-info
   Warning: Consider passing '-g' option to ocamlc.
   $ node _build/default/src/main.bc.wasm.js
   unknown
-  $ dune install --prefix _install --display short 2>&1 | sed 's/-[a-f0-9]*[.]wasm/.wasm/'
-  Deleting _install/lib/main/META
-  Installing _install/lib/main/META
-  Deleting _install/lib/main/dune-package
-  Installing _install/lib/main/dune-package
-  Deleting _install/lib/main/opam
-  Installing _install/lib/main/opam
-  Deleting _install/bin/main
-  Installing _install/bin/main
-  Deleting _install/bin/main.bc.wasm.assets/build_info.wasm
-  Installing _install/bin/main.bc.wasm.assets/build_info.wasm
-  Deleting _install/bin/main.bc.wasm.assets/build_info.wasm.map
-  Installing _install/bin/main.bc.wasm.assets/build_info.wasm.map
-  Installing _install/bin/main.bc.wasm.assets/build_info__Build_info_data.wasm
-  Installing _install/bin/main.bc.wasm.assets/build_info__Build_info_data.wasm.map
-  Deleting _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm
-  Installing _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm
-  Deleting _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm.map
-  Installing _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm.map
-  Deleting _install/bin/main.bc.wasm.assets/prelude.wasm
-  Installing _install/bin/main.bc.wasm.assets/prelude.wasm
-  Deleting _install/bin/main.bc.wasm.assets/runtime.wasm
-  Installing _install/bin/main.bc.wasm.assets/runtime.wasm
-  Deleting _install/bin/main.bc.wasm.assets/start.wasm
-  Installing _install/bin/main.bc.wasm.assets/start.wasm
-  Deleting _install/bin/main.bc.wasm.assets/std_exit.wasm
-  Installing _install/bin/main.bc.wasm.assets/std_exit.wasm
-  Deleting _install/bin/main.bc.wasm.assets/std_exit.wasm.map
-  Installing _install/bin/main.bc.wasm.assets/std_exit.wasm.map
-  Deleting _install/bin/main.bc.wasm.assets/stdlib.wasm
-  Installing _install/bin/main.bc.wasm.assets/stdlib.wasm
-  Deleting _install/bin/main.bc.wasm.assets/stdlib.wasm.map
-  Installing _install/bin/main.bc.wasm.assets/stdlib.wasm.map
-  Deleting _install/bin/main.bc.wasm.js
-  Installing _install/bin/main.bc.wasm.js
-  Installing _install/doc/main/README
+  $ dune install --prefix _install
+  $ find _install -type f | sed 's/-[a-f0-9]*[.]wasm/.wasm/' | sort -u
+  _install/bin/main
+  _install/bin/main.bc.wasm.assets/build_info.wasm
+  _install/bin/main.bc.wasm.assets/build_info.wasm.map
+  _install/bin/main.bc.wasm.assets/build_info__Build_info_data.wasm
+  _install/bin/main.bc.wasm.assets/build_info__Build_info_data.wasm.map
+  _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm
+  _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm.map
+  _install/bin/main.bc.wasm.assets/prelude.wasm
+  _install/bin/main.bc.wasm.assets/runtime.wasm
+  _install/bin/main.bc.wasm.assets/start.wasm
+  _install/bin/main.bc.wasm.assets/std_exit.wasm
+  _install/bin/main.bc.wasm.assets/std_exit.wasm.map
+  _install/bin/main.bc.wasm.assets/stdlib.wasm
+  _install/bin/main.bc.wasm.assets/stdlib.wasm.map
+  _install/bin/main.bc.wasm.js
+  _install/doc/main/README
+  _install/lib/main/META
+  _install/lib/main/dune-package
+  _install/lib/main/opam
   $ node _install/bin/main.bc.wasm.js
   v1-1-xxxxx-dirty
   $ echo "(name main)" >> dune-project
@@ -84,42 +70,26 @@ Jsoo and build-info
   Warning: Consider passing '-g' option to ocamlc.
   $ node _build/default/src/main.bc.wasm.js
   0.2.0
-  $ dune install --prefix _install --display short 2>&1 | sed 's/-[a-f0-9]*[.]wasm/.wasm/'
-  Deleting _install/lib/main/META
-  Installing _install/lib/main/META
-  Deleting _install/lib/main/dune-package
-  Installing _install/lib/main/dune-package
-  Deleting _install/lib/main/opam
-  Installing _install/lib/main/opam
-  Deleting _install/bin/main
-  Installing _install/bin/main
-  Deleting _install/bin/main.bc.wasm.assets/build_info.wasm
-  Installing _install/bin/main.bc.wasm.assets/build_info.wasm
-  Deleting _install/bin/main.bc.wasm.assets/build_info.wasm.map
-  Installing _install/bin/main.bc.wasm.assets/build_info.wasm.map
-  Installing _install/bin/main.bc.wasm.assets/build_info__Build_info_data.wasm
-  Installing _install/bin/main.bc.wasm.assets/build_info__Build_info_data.wasm.map
-  Deleting _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm
-  Installing _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm
-  Deleting _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm.map
-  Installing _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm.map
-  Deleting _install/bin/main.bc.wasm.assets/prelude.wasm
-  Installing _install/bin/main.bc.wasm.assets/prelude.wasm
-  Deleting _install/bin/main.bc.wasm.assets/runtime.wasm
-  Installing _install/bin/main.bc.wasm.assets/runtime.wasm
-  Deleting _install/bin/main.bc.wasm.assets/start.wasm
-  Installing _install/bin/main.bc.wasm.assets/start.wasm
-  Deleting _install/bin/main.bc.wasm.assets/std_exit.wasm
-  Installing _install/bin/main.bc.wasm.assets/std_exit.wasm
-  Deleting _install/bin/main.bc.wasm.assets/std_exit.wasm.map
-  Installing _install/bin/main.bc.wasm.assets/std_exit.wasm.map
-  Deleting _install/bin/main.bc.wasm.assets/stdlib.wasm
-  Installing _install/bin/main.bc.wasm.assets/stdlib.wasm
-  Deleting _install/bin/main.bc.wasm.assets/stdlib.wasm.map
-  Installing _install/bin/main.bc.wasm.assets/stdlib.wasm.map
-  Deleting _install/bin/main.bc.wasm.js
-  Installing _install/bin/main.bc.wasm.js
-  Deleting _install/doc/main/README
-  Installing _install/doc/main/README
+  $ dune install --prefix _install
+  $ find _install -type f | sed 's/-[a-f0-9]*[.]wasm/.wasm/' | sort -u
+  _install/bin/main
+  _install/bin/main.bc.wasm.assets/build_info.wasm
+  _install/bin/main.bc.wasm.assets/build_info.wasm.map
+  _install/bin/main.bc.wasm.assets/build_info__Build_info_data.wasm
+  _install/bin/main.bc.wasm.assets/build_info__Build_info_data.wasm.map
+  _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm
+  _install/bin/main.bc.wasm.assets/dune__exe__Main.wasm.map
+  _install/bin/main.bc.wasm.assets/prelude.wasm
+  _install/bin/main.bc.wasm.assets/runtime.wasm
+  _install/bin/main.bc.wasm.assets/start.wasm
+  _install/bin/main.bc.wasm.assets/std_exit.wasm
+  _install/bin/main.bc.wasm.assets/std_exit.wasm.map
+  _install/bin/main.bc.wasm.assets/stdlib.wasm
+  _install/bin/main.bc.wasm.assets/stdlib.wasm.map
+  _install/bin/main.bc.wasm.js
+  _install/doc/main/README
+  _install/lib/main/META
+  _install/lib/main/dune-package
+  _install/lib/main/opam
   $ node _build/default/src/main.bc.wasm.js
   0.2.0
diff --git a/test/blackbox-tests/test-cases/wasmoo/inline-tests.t/run.t b/test/blackbox-tests/test-cases/wasmoo/inline-tests.t/run.t
index e1f34332d63..51c9af3f5e0 100644
--- a/test/blackbox-tests/test-cases/wasmoo/inline-tests.t/run.t
+++ b/test/blackbox-tests/test-cases/wasmoo/inline-tests.t/run.t
@@ -16,7 +16,7 @@ Run inline tests using Node.js
   inline tests (Wasm)
   inline tests (Wasm)
 
-  $ dune build wasm/.inline_tests_wasm.inline-tests/inline_test_runner_inline_tests_wasm.bc --display short
+  $ dune build wasm/.inline_tests_wasm.inline-tests/inline_test_runner_inline_tests_wasm.bc
   Error: Don't know how to build
   wasm/.inline_tests_wasm.inline-tests/inline_test_runner_inline_tests_wasm.bc
   [1]
diff --git a/test/blackbox-tests/test-cases/wasmoo/no-check-prim.t/run.t b/test/blackbox-tests/test-cases/wasmoo/no-check-prim.t/run.t
index f51917e74ec..5626ee63b83 100644
--- a/test/blackbox-tests/test-cases/wasmoo/no-check-prim.t/run.t
+++ b/test/blackbox-tests/test-cases/wasmoo/no-check-prim.t/run.t
@@ -1,35 +1,21 @@
 Compilation using WasmOO
 
-  $ dune build --display short bin/technologic.bc.wasm.js @install  2>&1 | \
-  > sed s,^\ *$(ocamlc -config-var c_compiler),\ \ C_COMPILER,g
-      ocamldep bin/.technologic.eobjs/dune__exe__Technologic.impl.d
-      ocamldep lib/.x.objs/x.impl.d
-        ocamlc lib/.x.objs/byte/x__.{cmi,cmo,cmt}
-      ocamldep lib/.x.objs/x__Y.impl.d
-  wasm_of_ocaml bin/.technologic.eobjs/jsoo/technologic.bc.runtime.wasma
-      ocamldep bin/.technologic.eobjs/dune__exe__Z.impl.d
-      ocamlopt lib/.x.objs/native/x__.{cmx,o}
-        ocamlc lib/.x.objs/byte/x__Y.{cmi,cmo,cmt}
-  wasm_of_ocaml .js/default/stdlib/stdlib.wasma
-  wasm_of_ocaml .js/default/stdlib/std_exit.wasmo
-        ocamlc bin/.technologic.eobjs/byte/dune__exe.{cmi,cmo,cmt}
-      ocamldep bin/.technologic.eobjs/dune__exe__Technologic.intf.d
-      ocamlopt lib/.x.objs/native/x__Y.{cmx,o}
-        ocamlc lib/.x.objs/byte/x.{cmi,cmo,cmt}
-  wasm_of_ocaml .js/default/js_of_ocaml-compiler.runtime/jsoo_runtime.wasma
-      ocamlopt lib/.x.objs/native/x.{cmx,o}
-        ocamlc bin/.technologic.eobjs/byte/dune__exe__Z.{cmi,cmo,cmt}
-        ocamlc lib/x.cma
-        ocamlc bin/.technologic.eobjs/byte/dune__exe__Technologic.{cmi,cmti}
-  wasm_of_ocaml .js/default/js_of_ocaml/js_of_ocaml.wasma
-      ocamlopt lib/x.{a,cmxa}
-        ocamlc bin/.technologic.eobjs/byte/dune__exe__Technologic.{cmo,cmt}
-  wasm_of_ocaml lib/.x.objs/jsoo/default/x.wasma
-      ocamlopt lib/x.cmxs
-  wasm_of_ocaml bin/.technologic.eobjs/jsoo/dune__exe.wasmo
-  wasm_of_ocaml bin/.technologic.eobjs/jsoo/dune__exe__Z.wasmo
-  wasm_of_ocaml bin/.technologic.eobjs/jsoo/dune__exe__Technologic.wasmo
-  wasm_of_ocaml bin/technologic.bc.wasm.{js,assets}
+  $ dune build bin/technologic.bc.wasm.js @install
+  $ dune trace cat | jq -r 'include "dune";
+  >   processes
+  > | select(.args.prog | test("wasm_of_ocaml$"))
+  > | .args | targets | .[] | sub("^_build/[^/]+/"; "")' | sort
+  .js/default/js_of_ocaml-compiler.runtime/jsoo_runtime.wasma
+  .js/default/js_of_ocaml/js_of_ocaml.wasma
+  .js/default/stdlib/std_exit.wasmo
+  .js/default/stdlib/stdlib.wasma
+  bin/.technologic.eobjs/jsoo/dune__exe.wasmo
+  bin/.technologic.eobjs/jsoo/dune__exe__Technologic.wasmo
+  bin/.technologic.eobjs/jsoo/dune__exe__Z.wasmo
+  bin/.technologic.eobjs/jsoo/runtime.bc.runtime.wasma
+  bin/technologic.bc.wasm.assets
+  bin/technologic.bc.wasm.js
+  lib/.x.objs/jsoo/default/x.wasma
   $ node ./_build/default/bin/technologic.bc.wasm.js
   buy it
   use it