diff --git a/jscomp/bsb/bsb_build_util.ml b/jscomp/bsb/bsb_build_util.ml
index db931f8b47..73e2f72f15 100644
--- a/jscomp/bsb/bsb_build_util.ml
+++ b/jscomp/bsb/bsb_build_util.ml
@@ -124,7 +124,9 @@ let resolve_bsb_magic_file ~cwd ~desc p : result  =
      mkp "/a/b/c/d"
    ]}
 *)
-let rec mkp dir = 
+let rec mkp dir =
+Bsb_log.info
+    "@{<info>mkp @} dir: %s @." dir;   
   if not (Sys.file_exists dir) then 
     let parent_dir  = Filename.dirname dir in
     if  parent_dir = Filename.current_dir_name then 
@@ -178,6 +180,7 @@ let rec walk_all_deps_aux
   (top : bool) 
   (dir : string) 
   (cb : package_context -> unit) =
+  let () = Bsb_log.info "@{<info>walk_all_deps_aux dir:@} %s @." dir in
   let bsconfig_json =  dir // Literals.bsconfig_json in
   match Ext_json_parse.parse_json_from_file bsconfig_json with
   | Obj {map; loc} ->
@@ -229,5 +232,31 @@ let rec walk_all_deps_aux
     
 
 let walk_all_deps dir cb = 
-  let visited = String_hashtbl.create 0 in 
+  let visited = String_hashtbl.create 0 in
+  Bsb_log.info "@{<info>walk_all_deps dir:@} %s @." dir;
   walk_all_deps_aux visited [] true dir cb 
+
+let build_artifacts_dir = ref None
+
+let get_build_artifacts_location cwd =
+  let () = Bsb_log.info "@{<info>get_build_artifacts_location cwd:@} %s @." cwd in
+  let () = Bsb_log.info "@{<info>get_build_artifacts_location cur__root:@} %s @." (Sys.getenv "cur__root") in
+  let bad = match !build_artifacts_dir with
+  | Some(x) -> x
+  | None -> "not_set" in
+  let () = Bsb_log.info "@{<info>build_artifacts_dir:@} %s @." bad in
+  (* If the project's parent folder is not node_modules, we know it's the top level one. *)
+  if Sys.getenv "cur__root" = cwd then 
+    match !build_artifacts_dir with 
+    | None -> cwd
+    | Some dir -> dir
+  else begin
+    match !build_artifacts_dir with 
+    | None ->
+      cwd
+      (* (Filename.dirname (Filename.dirname cwd)) // Bsb_config.lib_lit // Bsb_config.node_modules // project_name *)
+    | Some dir ->
+      let project_name = Filename.basename cwd in
+      let () = Bsb_log.info "@{<info>build_artifacts_location:@} %s @." (dir // Bsb_config.lib_js // project_name) in
+      dir // Bsb_config.lib_js // project_name
+  end
diff --git a/jscomp/bsb/bsb_build_util.mli b/jscomp/bsb/bsb_build_util.mli
index 4cd099763b..cc9cd89ddb 100644
--- a/jscomp/bsb/bsb_build_util.mli
+++ b/jscomp/bsb/bsb_build_util.mli
@@ -96,3 +96,7 @@ type package_context = {
 }
 
 val walk_all_deps : string -> (package_context -> unit) -> unit
+
+val build_artifacts_dir : (string option) ref
+
+val get_build_artifacts_location : string -> string 
diff --git a/jscomp/bsb/bsb_clean.ml b/jscomp/bsb/bsb_clean.ml
index 26773364d0..33c5ad1a9f 100644
--- a/jscomp/bsb/bsb_clean.ml
+++ b/jscomp/bsb/bsb_clean.ml
@@ -39,7 +39,8 @@ let ninja_clean  proj_dir =
     Bsb_log.warn "@{<warning>ninja clean failed@} : %s @." (Printexc.to_string e)
 
 let clean_bs_garbage proj_dir =
-  Bsb_log.info "@{<info>Cleaning:@} in %s@." proj_dir ;
+  let proj_dir = Bsb_build_util.get_build_artifacts_location proj_dir in
+  let () = Bsb_log.info "@{<info>Cleaning:@} in %s@." proj_dir in
   let try_remove x =
     let x = proj_dir // x in
     if Sys.file_exists x then
@@ -56,8 +57,7 @@ let clean_bs_garbage proj_dir =
 let clean_bs_deps  proj_dir =
   Bsb_build_util.walk_all_deps  proj_dir  (fun pkg_cxt ->
       (* whether top or not always do the cleaning *)
-      clean_bs_garbage  pkg_cxt.proj_dir
+      clean_bs_garbage (Bsb_build_util.get_build_artifacts_location proj_dir)
     )
 
-let clean_self  proj_dir = 
-    clean_bs_garbage  proj_dir
+let clean_self proj_dir = clean_bs_garbage  (Bsb_build_util.get_build_artifacts_location proj_dir)
diff --git a/jscomp/bsb/bsb_config.ml b/jscomp/bsb/bsb_config.ml
index e468ad97e5..06a87d1582 100644
--- a/jscomp/bsb/bsb_config.ml
+++ b/jscomp/bsb/bsb_config.ml
@@ -45,6 +45,9 @@ let rev_lib_bs_prefix p = rev_lib_bs // p
 
 let ocaml_bin_install_prefix p = lib_ocaml // p
 
+let lazy_build_artifacts_dir = "$build_artifacts_dir"
+let build_artifacts_dir path = lazy_build_artifacts_dir // path
+
 let lazy_src_root_dir = "$src_root_dir" 
 let proj_rel path = lazy_src_root_dir // path
 
@@ -56,6 +59,4 @@ let proj_rel path = lazy_src_root_dir // path
 
 
 
-
 let cmd_package_specs = ref None 
-
diff --git a/jscomp/bsb/bsb_config.mli b/jscomp/bsb/bsb_config.mli
index 5725cfcca1..b144beb5de 100644
--- a/jscomp/bsb/bsb_config.mli
+++ b/jscomp/bsb/bsb_config.mli
@@ -24,6 +24,7 @@
 
 
 val ocaml_bin_install_prefix : string -> string
+val build_artifacts_dir : string -> string
 val proj_rel : string -> string
 
 val lib_js : string 
@@ -37,4 +38,3 @@ val rev_lib_bs_prefix : string -> string
 
 
 (** default not install, only when -make-world, its dependencies will be installed  *)
-
diff --git a/jscomp/bsb/bsb_config_parse.ml b/jscomp/bsb/bsb_config_parse.ml
index a88a1a858e..d4d1a27a44 100644
--- a/jscomp/bsb/bsb_config_parse.ml
+++ b/jscomp/bsb/bsb_config_parse.ml
@@ -30,7 +30,7 @@ let resolve_package cwd  package_name =
   let x =  Bsb_pkg.resolve_bs_package ~cwd package_name  in
   {
     Bsb_config_types.package_name ;
-    package_install_path = x // Bsb_config.lib_ocaml
+    package_install_path = (Bsb_build_util.get_build_artifacts_location x) // Bsb_config.lib_ocaml
   }
 
 type json_map = Ext_json_types.t String_map.t
diff --git a/jscomp/bsb/bsb_ninja_gen.ml b/jscomp/bsb/bsb_ninja_gen.ml
index 5a89a3a8db..df29b38c64 100644
--- a/jscomp/bsb/bsb_ninja_gen.ml
+++ b/jscomp/bsb/bsb_ninja_gen.ml
@@ -120,10 +120,10 @@ let output_ninja_and_namespace_map
       number_of_dev_groups;
     } : Bsb_config_types.t) : unit 
   =
-  
-  let cwd_lib_bs = per_proj_dir // Bsb_config.lib_bs in 
+  let build_artifacts_dir = Bsb_build_util.get_build_artifacts_location per_proj_dir in
+  let cwd_lib_bs = build_artifacts_dir // Bsb_config.lib_bs in 
   let ppx_flags = Bsb_build_util.ppx_flags ppx_files in
-  let oc = open_out_bin (cwd_lib_bs // Literals.build_ninja) in          
+  let oc = open_out_bin (cwd_lib_bs // Literals.build_ninja) in
   let g_pkg_flg , g_ns_flg = 
     match namespace with
     | None -> 
@@ -168,7 +168,8 @@ let output_ninja_and_namespace_map
            bs_dev_dependencies
            (fun x -> x.package_install_path));  
         Bsb_ninja_global_vars.g_ns , g_ns_flg ; 
-        Bsb_build_schemas.bsb_dir_group, "0"  (*TODO: avoid name conflict in the future *)
+        Bsb_build_schemas.bsb_dir_group, "0";  (*TODO: avoid name conflict in the future *)
+        Bsb_ninja_global_vars.build_artifacts_dir, build_artifacts_dir;
       |] oc 
   in        
   let  bs_groups, bsc_lib_dirs, static_resources =    
@@ -190,6 +191,7 @@ let output_ninja_and_namespace_map
       let static_resources =
         Ext_list.fold_left bs_file_groups [] (fun (acc_resources : string list) {sources; dir; resources; dir_index} 
            ->
+            let () = Bsb_log.info "@{<info>bs_file_groups dir:@} %s @." dir in
             let dir_index = (dir_index :> int) in 
             bs_groups.(dir_index) <- Bsb_db_util.merge bs_groups.(dir_index) sources ;
             source_dirs.(dir_index) <- dir :: source_dirs.(dir_index);
@@ -244,7 +246,7 @@ let output_ninja_and_namespace_map
 
   Ext_option.iter  namespace (fun ns -> 
       let namespace_dir =     
-        per_proj_dir // Bsb_config.lib_bs  in
+        build_artifacts_dir // Bsb_config.lib_bs  in
       Bsb_namespace_map_gen.output 
         ~dir:namespace_dir ns
         bs_file_groups; 
diff --git a/jscomp/bsb/bsb_ninja_global_vars.ml b/jscomp/bsb/bsb_ninja_global_vars.ml
index 611c9c3f1f..d2d2cda6b2 100644
--- a/jscomp/bsb/bsb_ninja_global_vars.ml
+++ b/jscomp/bsb/bsb_ninja_global_vars.ml
@@ -50,9 +50,11 @@ let g_ns = "g_ns"
 
 let warnings = "warnings"
 
+let build_artifacts_dir = "build_artifacts_dir"
+
 let gentypeconfig = "gentypeconfig"
 
 let g_dev_incls = "g_dev_incls"
 
 (* path to stdlib *)
-let g_stdlib_incl = "g_std_incl"
\ No newline at end of file
+let g_stdlib_incl = "g_std_incl"
diff --git a/jscomp/bsb/bsb_ninja_regen.ml b/jscomp/bsb/bsb_ninja_regen.ml
index 80e378b075..df32f17cd9 100644
--- a/jscomp/bsb/bsb_ninja_regen.ml
+++ b/jscomp/bsb/bsb_ninja_regen.ml
@@ -34,9 +34,16 @@ let regenerate_ninja
     ~(toplevel_package_specs : Bsb_package_specs.t option)
     ~forced ~per_proj_dir
   : Bsb_config_types.t option =  
+  let build_artifacts_dir = Bsb_build_util.get_build_artifacts_location per_proj_dir in
   let toplevel = toplevel_package_specs = None in 
-  let lib_bs_dir =  per_proj_dir // Bsb_config.lib_bs  in 
+  let lib_bs_dir =  build_artifacts_dir // Bsb_config.lib_bs  in
   let output_deps = lib_bs_dir // bsdeps in
+  let () = Bsb_log.info
+    "@{<info>regenerate_ninja@} per_proj_dir : %s @." per_proj_dir in
+  let () = Bsb_log.info
+    "@{<info>regenerate_ninja@} lib_bs_dir : %s @." lib_bs_dir in
+  let () = Bsb_log.info
+    "@{<info>regenerate_ninja@} output_deps : %s @." output_deps in
   let check_result  =
     Bsb_ninja_check.check 
       ~per_proj_dir:per_proj_dir  
@@ -53,26 +60,32 @@ let regenerate_ninja
   | Other _ -> 
     if check_result = Bsb_bsc_version_mismatch then begin 
       Bsb_log.warn "@{<info>Different compiler version@}: clean current repo@.";
-      Bsb_clean.clean_self  per_proj_dir; 
-    end ; 
+      Bsb_clean.clean_self  build_artifacts_dir; 
+    end ;
     
     let config = 
       Bsb_config_parse.interpret_json 
         ~toplevel_package_specs
         ~per_proj_dir in 
+        
     (* create directory, lib/bs, lib/js, lib/es6 etc *)    
-    Bsb_build_util.mkp lib_bs_dir;         
+    Bsb_build_util.mkp build_artifacts_dir;      
+   
     Bsb_package_specs.list_dirs_by config.package_specs
-      (fun x -> 
-        let dir = per_proj_dir // x in (*Unix.EEXIST error*)
+      (fun x ->
+        let dir = build_artifacts_dir // x in (*Unix.EEXIST error*)
         if not (Sys.file_exists dir) then  Unix.mkdir dir 0o777);
-    if toplevel then       
-      Bsb_watcher_gen.generate_sourcedirs_meta
-        ~name:(lib_bs_dir // Literals.sourcedirs_meta)
-        config.file_groups
+    if toplevel then
+      begin
+        Bsb_log.info "@{<info>toplevel@} %s @." (lib_bs_dir // Literals.sourcedirs_meta);
+        Bsb_watcher_gen.generate_sourcedirs_meta
+          ~name:(lib_bs_dir // Literals.sourcedirs_meta)
+          config.file_groups
+      end
     ;
-    Bsb_merlin_gen.merlin_file_gen ~per_proj_dir
-      (Bsb_global_paths.vendor_bsppx) config;       
+    
+    (*Bsb_merlin_gen.merlin_file_gen ~per_proj_dir
+      (Bsb_global_paths.vendor_bsppx) config;*)
     Bsb_ninja_gen.output_ninja_and_namespace_map 
       ~per_proj_dir  ~toplevel config ;             
     
@@ -81,5 +94,3 @@ let regenerate_ninja
     Bsb_ninja_check.record ~per_proj_dir ~file:output_deps 
       (Literals.bsconfig_json::config.file_groups.globbed_dirs) ;
     Some config 
-
-
diff --git a/jscomp/bsb/bsb_package_specs.ml b/jscomp/bsb/bsb_package_specs.ml
index 78539536d6..2986645083 100644
--- a/jscomp/bsb/bsb_package_specs.ml
+++ b/jscomp/bsb/bsb_package_specs.ml
@@ -131,8 +131,7 @@ let package_flag ({format; in_source } : spec) dir =
     (Ext_string.concat3
        (string_of_format format)
        Ext_string.single_colon
-       (if in_source then dir else
-        prefix_of_format format // dir))
+         dir)
 
 let package_flag_of_package_specs (package_specs : t) 
     (dirname : string ) : string  = 
@@ -161,7 +160,7 @@ let get_list_of_output_js
              output_file_sans_extension
              (if bs_suffix then Literals.suffix_bs_js else Literals.suffix_js)
         in 
-        (Bsb_config.proj_rel @@ (if spec.in_source then basename
+        (Bsb_config.build_artifacts_dir @@ (if spec.in_source then basename
         else prefix_of_format spec.format // basename))         
        :: acc
     ) package_specs []
@@ -174,4 +173,4 @@ let list_dirs_by
   Spec_set.iter (fun (spec : spec)  -> 
     if not spec.in_source then     
       f (prefix_of_format spec.format) 
-  ) package_specs 
\ No newline at end of file
+  ) package_specs 
diff --git a/jscomp/bsb/bsb_parse_sources.ml b/jscomp/bsb/bsb_parse_sources.ml
index 818ac24cb5..e90d22c91f 100644
--- a/jscomp/bsb/bsb_parse_sources.ml
+++ b/jscomp/bsb/bsb_parse_sources.ml
@@ -501,4 +501,3 @@ let clean_re_js root =
     end
   | _  -> () 
   | exception _ -> ()    
-  
\ No newline at end of file
diff --git a/jscomp/bsb/bsb_world.ml b/jscomp/bsb/bsb_world.ml
index 154598f7ad..a797dce5e5 100644
--- a/jscomp/bsb/bsb_world.ml
+++ b/jscomp/bsb/bsb_world.ml
@@ -68,15 +68,17 @@ let build_bs_deps cwd (deps : Bsb_package_specs.t) (ninja_args : string array) =
   in 
   Bsb_build_util.walk_all_deps  cwd (fun {top; proj_dir} ->
       if not top then
-        begin 
+        begin
+          let () = Bsb_log.info "@{<info>build_bs_deps proj_dir:@} %s @." proj_dir in
           let config_opt = 
             Bsb_ninja_regen.regenerate_ninja 
               ~toplevel_package_specs:(Some deps) 
               ~forced:true
               ~per_proj_dir:proj_dir  in (* set true to force regenrate ninja file so we have [config_opt]*)
+          let build_artifacts_dir = Bsb_build_util.get_build_artifacts_location proj_dir in
           let command = 
             {Bsb_unix.cmd = vendor_ninja;
-             cwd = proj_dir // Bsb_config.lib_bs;
+             cwd = build_artifacts_dir // Bsb_config.lib_bs;
              args 
             } in     
           let eid =
@@ -89,7 +91,7 @@ let build_bs_deps cwd (deps : Bsb_package_specs.t) (ninja_args : string array) =
              Note that we can check if ninja print "no work to do", 
              then don't need reinstall more
           *)
-          Ext_option.iter config_opt (install_targets proj_dir);
+          Ext_option.iter config_opt (install_targets build_artifacts_dir);
         end
     )
 
@@ -105,4 +107,4 @@ let make_world_deps cwd (config : Bsb_config_types.t option) (ninja_args : strin
       *)
       Bsb_config_parse.package_specs_from_bsconfig ()
     | Some config -> config.package_specs in
-  build_bs_deps cwd deps ninja_args
\ No newline at end of file
+  build_bs_deps cwd deps ninja_args
diff --git a/jscomp/main/bsb_main.ml b/jscomp/main/bsb_main.ml
index 8e456fd662..65baea2b38 100644
--- a/jscomp/main/bsb_main.ml
+++ b/jscomp/main/bsb_main.ml
@@ -89,22 +89,22 @@ let exec_command_then_exit  command =
   exit (Sys.command command ) 
 
 (* Execute the underlying ninja build call, then exit (as opposed to keep watching) *)
-let ninja_command_exit   ninja_args  =
+let ninja_command_exit cwd ninja_args  =
   let ninja_args_len = Array.length ninja_args in
   if Ext_sys.is_windows_or_cygwin then
     let path_ninja = Filename.quote Bsb_global_paths.vendor_ninja in 
     exec_command_then_exit 
       (if ninja_args_len = 0 then      
          Ext_string.inter3
-           path_ninja "-C" Bsb_config.lib_bs
+           path_ninja "-C" (cwd // Bsb_config.lib_bs)
        else   
          let args = 
            Array.append 
-             [| path_ninja ; "-C"; Bsb_config.lib_bs|]
+             [| path_ninja ; "-C"; cwd // Bsb_config.lib_bs|]
              ninja_args in 
          Ext_string.concat_array Ext_string.single_space args)
   else
-    let ninja_common_args = [|"ninja.exe"; "-C"; Bsb_config.lib_bs |] in 
+    let ninja_common_args = [|"ninja.exe"; "-C"; cwd // Bsb_config.lib_bs |] in 
     let args = 
       if ninja_args_len = 0 then ninja_common_args else 
         Array.append ninja_common_args ninja_args in 
@@ -160,6 +160,9 @@ let install_target config_opt =
 
 (* see discussion #929, if we catch the exception, we don't have stacktrace... *)
 let () =
+  let getenv_opt env = try Some(Sys.getenv env)
+  with | Not_found -> None in
+  let () = Bsb_build_util.build_artifacts_dir := getenv_opt "cur__target_dir" in
   try begin 
     match Sys.argv with 
     | [| _ |] ->  (* specialize this path [bsb.exe] which is used in watcher *)
@@ -167,7 +170,7 @@ let () =
         ~toplevel_package_specs:None 
         ~forced:false 
         ~per_proj_dir:Bsb_global_paths.cwd  |> ignore;
-      ninja_command_exit  [||] 
+      ninja_command_exit (Bsb_build_util.get_build_artifacts_location Bsb_global_paths.cwd) [||] 
 
     | argv -> 
       begin
@@ -208,7 +211,7 @@ let () =
                       [bsb -regen ]
                    *)
                  end else if make_world then begin
-                   ninja_command_exit [||] 
+                   ninja_command_exit (Bsb_build_util.get_build_artifacts_location Bsb_global_paths.cwd) [||] 
                  end else if do_install then begin
                    install_target config_opt
                  end)
@@ -228,7 +231,7 @@ let () =
             if !do_install then
               install_target config_opt;
             if !watch_mode then program_exit ()
-            else ninja_command_exit  ninja_args 
+            else ninja_command_exit (Bsb_build_util.get_build_artifacts_location Bsb_global_paths.cwd) ninja_args 
           end
       end
   end