diff --git a/db/builder_db.ml b/db/builder_db.ml
index cdcd190..13d63ce 100644
--- a/db/builder_db.ml
+++ b/db/builder_db.ml
@@ -11,7 +11,6 @@ type 'a id = 'a Rep.id
 
 type file = Rep.file = {
   filepath : Fpath.t;
-  localpath : Fpath.t;
   sha256 : Cstruct.t;
   size : int;
 }
@@ -140,7 +139,6 @@ module Build_artifact = struct
     {| CREATE TABLE build_artifact (
            id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
            filepath TEXT NOT NULL, -- the path as in the build
-           localpath TEXT NOT NULL, -- local path to the file on disk
            sha256 BLOB NOT NULL,
            size INTEGER NOT NULL,
            build INTEGER NOT NULL,
@@ -156,13 +154,13 @@ module Build_artifact = struct
 
   let get =
     id `build_artifact ->! file @@
-    {| SELECT filepath, localpath, sha256, size
+    {| SELECT filepath, sha256, size
        FROM build_artifact WHERE id = ? |}
 
   let get_by_build_uuid =
     Caqti_type.tup2 uuid fpath ->? Caqti_type.tup2 (id `build_artifact) file @@
     {| SELECT build_artifact.id, build_artifact.filepath,
-         build_artifact.localpath, build_artifact.sha256, build_artifact.size
+         build_artifact.sha256, build_artifact.size
        FROM build_artifact
        INNER JOIN build ON build.id = build_artifact.build
        WHERE build.uuid = ? AND build_artifact.filepath = ?
@@ -170,11 +168,15 @@ module Build_artifact = struct
 
   let get_all_by_build =
     id `build ->* Caqti_type.(tup2 (id `build_artifact) file) @@
-    "SELECT id, filepath, localpath, sha256, size FROM build_artifact WHERE build = ?"
+    "SELECT id, filepath, sha256, size FROM build_artifact WHERE build = ?"
+
+  let exists =
+    cstruct ->! Caqti_type.bool @@
+    "SELECT EXISTS(SELECT 1 FROM build_artifact WHERE sha256 = ?"
 
   let add =
     Caqti_type.(tup2 file (id `build)) ->. Caqti_type.unit @@
-    "INSERT INTO build_artifact (filepath, localpath, sha256, size, build) \
+    "INSERT INTO build_artifact (filepath, sha256, size, build) \
      VALUES (?, ?, ?, ?, ?)"
 
   let remove_by_build =
@@ -316,7 +318,7 @@ module Build = struct
          b.uuid, b.start_d, b.start_ps, b.finish_d, b.finish_ps,
          b.result_code, b.result_msg, b.console, b.script,
          b.platform, b.main_binary, b.input_id, b.user, b.job,
-         a.filepath, a.localpath, a.sha256, a.size
+         a.filepath, a.sha256, a.size
        FROM build b, build_artifact a
        WHERE b.main_binary = a.id AND b.job = $1 AND b.platform = $2
          AND b.main_binary IS NOT NULL
@@ -442,7 +444,7 @@ module Build = struct
     {| SELECT b.uuid, b.start_d, b.start_ps, b.finish_d, b.finish_ps,
             b.result_code, b.result_msg, b.console, b.script,
             b.platform, b.main_binary, b.input_id, b.user, b.job,
-            a.filepath, a.localpath, a.sha256, a.size
+            a.filepath, a.sha256, a.size
        FROM build_artifact a
        INNER JOIN build b ON b.id = a.build
        WHERE a.sha256 = ?
@@ -593,6 +595,8 @@ let migrate = [
   "CREATE INDEX idx_build_main_binary ON build(main_binary)";
   Caqti_type.unit ->. Caqti_type.unit @@
   "CREATE INDEX idx_build_artifact_sha256 ON build_artifact(sha256)";
+  Caqti_type.unit ->. Caqti_type.unit @@
+  "CREATE INDEX idx_build_artifact_build ON build_artifact(build)";
   set_current_version;
   set_application_id;
 ]
@@ -606,6 +610,8 @@ let rollback = [
   Build.rollback;
   Job.rollback;
   Caqti_type.unit ->. Caqti_type.unit @@
+  "DROP INDEX IF EXISTS idx_build_artifact_build";
+  Caqti_type.unit ->. Caqti_type.unit @@
   "DROP INDEX IF EXISTS idx_build_artifact_sha256";
   Caqti_type.unit ->. Caqti_type.unit @@
   "DROP INDEX IF EXISTS idx_build_failed";
diff --git a/db/builder_db.mli b/db/builder_db.mli
index 2988c12..9d1f052 100644
--- a/db/builder_db.mli
+++ b/db/builder_db.mli
@@ -3,7 +3,6 @@ module Rep : sig
   type 'a id
   type file = {
     filepath : Fpath.t;
-    localpath : Fpath.t;
     sha256 : Cstruct.t;
     size : int;
   }
@@ -23,7 +22,6 @@ type 'a id = 'a Rep.id
 
 type file = Rep.file = {
   filepath : Fpath.t;
-  localpath : Fpath.t;
   sha256 : Cstruct.t;
   size : int;
 }
@@ -87,6 +85,7 @@ module Build_artifact : sig
       Caqti_request.t
   val get_all_by_build :
     ([`build] id, [`build_artifact] id * file, [ `Many | `One | `Zero ]) Caqti_request.t
+  val exists : (Cstruct.t, bool, [ `One ]) Caqti_request.t
   val add :
     (file * [`build] id, unit, [ `Zero ]) Caqti_request.t
   val remove_by_build :
diff --git a/db/representation.ml b/db/representation.ml
index 4d94b93..1cc1722 100644
--- a/db/representation.ml
+++ b/db/representation.ml
@@ -30,7 +30,6 @@ let id_to_int64 (id : 'a id) : int64 = id
 
 type file = {
   filepath : Fpath.t;
-  localpath : Fpath.t;
   sha256 : Cstruct.t;
   size : int;
 }
@@ -63,24 +62,24 @@ let cstruct =
   Caqti_type.custom ~encode ~decode Caqti_type.octets
 
 let file =
-  let encode { filepath; localpath; sha256; size } =
-    Ok (filepath, localpath, sha256, size) in
-  let decode (filepath, localpath, sha256, size) =
-    Ok { filepath; localpath; sha256; size } in
-  Caqti_type.custom ~encode ~decode Caqti_type.(tup4 fpath fpath cstruct int)
+  let encode { filepath; sha256; size } =
+    Ok (filepath, sha256, size) in
+  let decode (filepath, sha256, size) =
+    Ok { filepath; sha256; size } in
+  Caqti_type.custom ~encode ~decode Caqti_type.(tup3 fpath cstruct int)
 
 let file_opt =
-  let rep = Caqti_type.(tup4 (option fpath) (option fpath) (option cstruct) (option int)) in
+  let rep = Caqti_type.(tup3 (option fpath) (option cstruct) (option int)) in
   let encode = function
-    | Some { filepath; localpath; sha256; size } ->
-      Ok (Some filepath, Some localpath, Some sha256, Some size)
+    | Some { filepath; sha256; size } ->
+      Ok (Some filepath, Some sha256, Some size)
     | None ->
-      Ok (None, None, None, None)
+      Ok (None, None, None)
   in
   let decode = function
-    | (Some filepath, Some localpath, Some sha256, Some size) ->
-      Ok (Some { filepath; localpath; sha256; size })
-    | (None, None, None, None) ->
+    | (Some filepath, Some sha256, Some size) ->
+      Ok (Some { filepath; sha256; size })
+    | (None, None, None) ->
       Ok None
     | _ ->
       (* This should not happen if the database is well-formed *)
diff --git a/lib/builder_web.ml b/lib/builder_web.ml
index 4a40dcf..feb596e 100644
--- a/lib/builder_web.ml
+++ b/lib/builder_web.ml
@@ -211,9 +211,9 @@ module Viz_aux = struct
     match typ with
     | `Treemap ->
       let debug_binary = 
-        let bin = Fpath.base main_binary.localpath in
+        let bin = Fpath.base main_binary.filepath in
         List.find_opt
-          (fun p -> Fpath.(equal (bin + "debug") (base p.localpath)))
+          (fun p -> Fpath.(equal (bin + "debug") (base p.filepath)))
           artifacts
       in
       begin
@@ -226,7 +226,7 @@ module Viz_aux = struct
     | `Dependencies -> 
       let opam_switch =
         List.find_opt
-          (fun p -> Fpath.(equal (v "opam-switch") (base p.localpath)))
+          (fun p -> Fpath.(equal (v "opam-switch") (base p.filepath)))
           artifacts
       in
       Model.not_found opam_switch
@@ -435,8 +435,8 @@ let routes ~datadir ~cachedir ~configdir ~expired_jobs =
     | _ ->
       Model.build_artifact_data datadir file
       |> if_error "Error getting build artifact"
-          ~log:(fun e -> Log.warn (fun m -> m "Error getting build artifact data for file %a in %a: %a"
-                           Fpath.pp file.Builder_db.filepath Fpath.pp file.Builder_db.localpath
+          ~log:(fun e -> Log.warn (fun m -> m "Error getting build artifact data for file %a: %a"
+                           Fpath.pp file.Builder_db.filepath
                            pp_error e)) >>= fun data ->
       let headers = [
         "Content-Type", mime_lookup file.Builder_db.filepath;
diff --git a/lib/dream_tar.ml b/lib/dream_tar.ml
index b5a5899..2cad5f6 100644
--- a/lib/dream_tar.ml
+++ b/lib/dream_tar.ml
@@ -67,7 +67,7 @@ let targz_response datadir finish (files : Builder_db.file list) (stream : Dream
   in
   Lwt_list.iter_s (fun file ->
       let hdr = header_of_file finish file in
-      write_block hdr Fpath.(datadir // file.localpath) state)
+      write_block hdr Fpath.(datadir // Model.artifact_path file) state)
     files >>= fun () ->
   Writer.really_write state Tar.Header.zero_block >>= fun () ->
   Writer.really_write state Tar.Header.zero_block >>= fun () ->
diff --git a/lib/model.ml b/lib/model.ml
index 91e25b4..ec62243 100644
--- a/lib/model.ml
+++ b/lib/model.ml
@@ -19,6 +19,15 @@ let not_found = function
   | Some v -> Lwt_result.return v
 
 let staging datadir = Fpath.(datadir / "_staging")
+let artifacts_dir datadir = Fpath.(datadir / "_artifacts")
+let artifact_path artifact =
+  let (`Hex sha256) = Hex.of_cstruct artifact.Builder_db.sha256 in
+  (* NOTE: [sha256] is 64 characters when it's a hex sha256 checksum *)
+  (* NOTE: We add the prefix to reduce the number of files in a directory - a
+     workaround for inferior filesystems. We can easily revert this by changing
+     this function and adding a migration. *)
+  let prefix = String.sub sha256 0 2 in
+  Fpath.(v "_artifacts" / prefix / sha256)
 
 let read_file datadir filepath =
   let filepath = Fpath.(datadir // filepath) in
@@ -44,14 +53,14 @@ let build_artifact_by_id id (module Db : CONN) =
   Db.find Builder_db.Build_artifact.get id
 
 let build_artifact_data datadir file =
-  read_file datadir file.Builder_db.localpath
+  read_file datadir (artifact_path file)
 
 let build_artifacts build (module Db : CONN) =
   Db.collect_list Builder_db.Build_artifact.get_all_by_build build >|=
   List.map snd
 
 let solo5_manifest datadir file =
-  let buf = Owee_buf.map_binary Fpath.(to_string (datadir // file.Builder_db.localpath)) in
+  let buf = Owee_buf.map_binary Fpath.(to_string (datadir // artifact_path file)) in
   Solo5_elftool.query_manifest buf |> Result.to_option
 
 let platforms_of_job id (module Db : CONN) =
@@ -196,11 +205,11 @@ let cleanup_staging datadir (module Db : Caqti_lwt.CONNECTION) =
        (cleanup_staged staged))
     stageds
 
-let save file data =
+let save path data =
   let open Lwt.Infix in
   Lwt.catch
     (fun () ->
-       Lwt_io.open_file ~mode:Lwt_io.Output (Fpath.to_string file) >>= fun oc ->
+       Lwt_io.open_file ~mode:Lwt_io.Output (Fpath.to_string path) >>= fun oc ->
        Lwt_io.write oc data >>= fun () ->
        Lwt_io.close oc
        |> Lwt_result.ok)
@@ -209,33 +218,30 @@ let save file data =
           Lwt_result.fail (`Msg (Unix.error_message e))
       | e -> Lwt.fail e)
 
-let save_file dir staging (filepath, data) =
-  let size = String.length data in
-  let sha256 = Mirage_crypto.Hash.SHA256.digest (Cstruct.of_string data) in
-  let localpath = Fpath.append dir filepath in
-  let destpath = Fpath.append staging filepath in
-  Lwt_result.lift (Bos.OS.Dir.create (Fpath.parent destpath)) >>= fun _ ->
-  save destpath data >|= fun () ->
-  { Builder_db.filepath; localpath; sha256; size }
-
-let save_files dir staging files =
+let save_artifacts staging artifacts =
   List.fold_left
-    (fun r file ->
-       r >>= fun acc ->
-       save_file dir staging file >>= fun file ->
-       Lwt_result.return (file :: acc))
-    (Lwt_result.return [])
-    files
+    (fun r (file, data) ->
+       r >>= fun () ->
+       let (`Hex sha256) = Hex.of_cstruct file.Builder_db.sha256 in
+       let destpath = Fpath.(staging / sha256) in
+       save destpath data)
+    (Lwt_result.return ())
+    artifacts
 
-let save_all staging_dir (job : Builder.script_job) uuid artifacts =
-  let build_dir = Fpath.(v job.Builder.name / Uuidm.to_string uuid) in
-  let output_dir = Fpath.(build_dir / "output")
-  and staging_output_dir = Fpath.(staging_dir / "output") in
-  Lwt.return (Bos.OS.Dir.create staging_output_dir) >>= fun _ ->
-  save_files output_dir staging_output_dir artifacts >>= fun artifacts ->
-  Lwt_result.return artifacts
-
-let commit_files datadir staging_dir job_name uuid =
+let commit_files datadir staging_dir job_name uuid artifacts =
+  (* First we move the artifacts *)
+  Lwt.return (Bos.OS.Dir.create (artifacts_dir datadir)) >>= fun _ ->
+  List.fold_left
+    (fun r artifact ->
+       r >>= fun () ->
+       let (`Hex sha256) = Hex.of_cstruct artifact.Builder_db.sha256 in
+       let src = Fpath.(staging_dir / sha256) in
+       let dest = Fpath.(datadir // artifact_path artifact) in
+       Lwt.return (Bos.OS.Dir.create (Fpath.parent dest)) >>= fun _created ->
+       Lwt.return (Bos.OS.Path.move ~force:true src dest))
+    (Lwt_result.return ())
+    artifacts >>= fun () ->
+  (* Now the staging dir only contains script & console *)
   let job_dir = Fpath.(datadir / job_name) in
   let dest = Fpath.(job_dir / Uuidm.to_string uuid) in
   Lwt.return (Bos.OS.Dir.create job_dir) >>= fun _ ->
@@ -324,6 +330,25 @@ let prepare_staging staging_dir =
   then Lwt_result.fail (`Msg "build directory already exists")
   else Lwt_result.return ()
 
+(* saving:
+   - for each artifact compute its sha256 checksum -- calling Lwt.pause in
+     between
+   - lookup artifact sha256 in the database and filter them out of the list: not_in_db
+   - mkdir -p _staging/uuid/
+   - save console & script to _staging/uuid/
+   - save each artifact in not_in_db as _staging/uuid/sha256
+   committing:
+   - for each artifact mv _staging/uuid/sha256 _artifacts/sha256
+     (or _artifacts/prefix(sha256)/sha256 where prefix(sha256) is the first two hex digits in sha256)
+   - now _staging/uuid only contains console & script so we mv _staging/uuid _staging/job/uuid
+   potential issues:
+   - race condition in uploading same artifact:
+     * if the artifact already exists in the database and thus filesystem then nothing is done
+     * if the artifact is added to the database and/or filesystem we atomically overwrite it
+   - input_id depends on a sort order?
+   *)
+
+
 let add_build
     ~datadir
     ~cachedir
@@ -344,16 +369,35 @@ let add_build
         e)
       x
   in
-  let artifacts_to_preserve =
-    let not_interesting p =
-      String.equal (Fpath.basename p) "README.md" || String.equal (Fpath.get_ext p) ".build-hashes"
-    in
-    List.filter (fun (p, _) -> not (not_interesting p)) raw_artifacts
+  let not_interesting p =
+    String.equal (Fpath.basename p) "README.md" || String.equal (Fpath.get_ext p) ".build-hashes"
   in
+  begin
+    List.fold_left
+      (fun r (filepath, data) ->
+         r >>= fun acc ->
+         if not_interesting filepath then
+           Lwt_result.return acc
+         else
+           let sha256 = Mirage_crypto.Hash.SHA256.digest (Cstruct.of_string data)
+           and size = String.length data in
+           Lwt_result.ok (Lwt.pause ()) >|= fun () ->
+           ({ filepath; sha256; size }, data) :: acc)
+      (Lwt_result.return [])
+      raw_artifacts
+  end >>= fun artifacts ->
   or_cleanup (prepare_staging staging_dir) >>= fun () ->
   or_cleanup (save_console_and_script staging_dir job_name uuid console job.Builder.script)
   >>= fun (console, script) ->
-  or_cleanup (save_all staging_dir job uuid artifacts_to_preserve) >>= fun artifacts ->
+  List.fold_left
+    (fun r ((f, _) as artifact) ->
+       r >>= fun acc ->
+       Db.find Builder_db.Build_artifact.exists f.sha256 >|= fun exists ->
+       if exists then acc else artifact :: acc)
+    (Lwt_result.return [])
+    artifacts >>= fun artifacts_to_save ->
+  or_cleanup (save_artifacts staging_dir artifacts_to_save) >>= fun () ->
+  let artifacts = List.map fst artifacts in
   let r =
     Db.start () >>= fun () ->
     Db.exec Job.try_add job_name >>= fun () ->
@@ -422,7 +466,7 @@ let add_build
       (Lwt_result.return ())
       remaining_artifacts_to_add >>= fun () ->
     Db.commit () >>= fun () ->
-    commit_files datadir staging_dir job_name uuid >|= fun () ->
+    commit_files datadir staging_dir job_name uuid artifacts >|= fun () ->
     main_binary
   in
   Lwt_result.bind_lwt_error (or_cleanup r)
@@ -451,7 +495,7 @@ let add_build
              "--uuid=" ^ uuid ; "--platform=" ^ platform ;
              "--cache-dir=" ^ Fpath.to_string cachedir ;
              "--data-dir=" ^ Fpath.to_string datadir ;
-             fp_str main_binary.localpath ])
+             fp_str Fpath.(datadir // artifact_path main_binary) ])
     in
     Log.debug (fun m -> m "executing hooks with %s" args);
     let dir = Fpath.(configdir / "upload-hooks") in
diff --git a/lib/model.mli b/lib/model.mli
index 2b36a7c..db38ae3 100644
--- a/lib/model.mli
+++ b/lib/model.mli
@@ -5,6 +5,8 @@ val pp_error : Format.formatter -> error -> unit
 val not_found : 'a option -> ('a, [> `Not_found ]) result Lwt.t
 
 val staging : Fpath.t -> Fpath.t
+val artifacts_dir : Fpath.t -> Fpath.t
+val artifact_path : Builder_db.file -> Fpath.t
 
 val cleanup_staging : Fpath.t -> Caqti_lwt.connection ->
   (unit, [> `Msg of string ]) result Lwt.t
diff --git a/lib/views.ml b/lib/views.ml
index 9e9e3e3..8a597f8 100644
--- a/lib/views.ml
+++ b/lib/views.ml
@@ -188,7 +188,7 @@ let artifact
     ~basename
     ~job_name
     ~build
-    ~file:{ Builder_db.filepath; localpath = _; sha256; size }
+    ~file:{ Builder_db.filepath; sha256; size }
   =
   let artifact_link =
     Link.Job_build_artifact.make