diff --git a/frontend/test/benches/render_wasm/upload.cljs b/frontend/test/benches/render_wasm/upload.cljs
new file mode 100644
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+++ b/frontend/test/benches/render_wasm/upload.cljs
@@ -0,0 +1,35 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+;;
+;; Copyright (c) KALEIDOS SUBSIDIARY SL
+
+(ns benches.render-wasm.upload
+  "Benchmark scene upload.
+
+  In order to emulate editor behaviour, `upload-scene!` derives
+  parent-before-child order from a validated scene
+  snapshot and uploads it with `serialize-shapes-batch!`
+
+  Validation, timing, lifecycle (`_begin/_end_loading`), host font/image/grid
+  sequencing and text layouts stay in the callers (tickets 02/05).
+
+  This uses renderer code, so don't pull this from Node case collection
+  (`benches.render-wasm.cases`)"
+  (:require
+   [app.common.render-wasm.serialize-shape :as serialize-shape]
+   [benches.render-wasm.scenes.common :as common]))
+
+(defn upload-scene!
+  "Uploads validated `snapshot` with `opts`.
+
+  - `snapshot` is `{:objects {uuid shape} :refs {label uuid}}` per the ticket02
+    contract; it must already be validated (see
+    `benches.render-wasm.scenes.common/validate!`).
+  - `opts` carries `:include-layout?` and `:include-fills-strokes?` through to
+    the batch writer.
+
+  Returns the prepared shape vector."
+  [snapshot opts]
+  (let [ordered (common/upload-order snapshot)]
+    (serialize-shape/serialize-shapes-batch! ordered opts)))
diff --git a/frontend/test/frontend_tests/benches/upload_test.cljs b/frontend/test/frontend_tests/benches/upload_test.cljs
new file mode 100644
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+++ b/frontend/test/frontend_tests/benches/upload_test.cljs
@@ -0,0 +1,60 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+;;
+;; Copyright (c) KALEIDOS SUBSIDIARY SL
+
+(ns frontend-tests.benches.upload-test
+  "Test routing contract for `benches.render-wasm.upload/upload-scene!`.
+
+  Byte layouts are proven by `frontend-tests.render-wasm.serialization-test`
+  and `process-objects-test`; this suite pins: the order comes from
+  `scenes.common/upload-order`, the batch helper is called exactly once with
+  the caller's opts, and the prepared vector is returned in order."
+  (:require
+   [app.common.render-wasm.api.upload :as upload]
+   [app.common.types.shape :as cts]
+   [app.common.uuid :as uuid]
+   [benches.render-wasm.scenes.common :as common]
+   [benches.render-wasm.upload :as bench-upload]
+   [cljs.test :as t :include-macros true]))
+
+(defn- sample-snapshot
+  "Root frame with two rectangles, so order is observable."
+  []
+  (let [r1-id (uuid/custom 11 1)
+        r2-id (uuid/custom 11 2)
+        r1    (cts/setup-shape {:id r1-id :type :rect :name "R1"
+                                :x 10 :y 10 :width 100 :height 60
+                                :parent-id uuid/zero :frame-id uuid/zero})
+        r2    (cts/setup-shape {:id r2-id :type :rect :name "R2"
+                                :x 200 :y 40 :width 80 :height 80
+                                :parent-id uuid/zero :frame-id uuid/zero})
+        root  (cts/setup-shape {:id uuid/zero :type :frame :name "Root Frame"
+                                :x 0 :y 0 :width 1920 :height 1080
+                                :parent-id uuid/zero :frame-id uuid/zero
+                                :shapes [r1-id r2-id]})]
+    {:objects {uuid/zero root, r1-id r1, r2-id r2}
+     :refs    {:r1 r1-id :r2 r2-id}}))
+
+(t/deftest upload-scene-uses-snapshot-order-and-caller-opts
+  (let [snapshot    (common/validate! (sample-snapshot))
+        opts        {:include-layout? false :include-fills-strokes? true}
+        flush-calls (atom [])
+        orig-flush  upload/flush-shapes-batch!
+        expected    (common/upload-order snapshot)]
+    (set! upload/flush-shapes-batch!
+          (fn [shapes o] (swap! flush-calls conj {:shapes shapes :opts o}) nil))
+    (try
+      (let [result (bench-upload/upload-scene! snapshot opts)
+            flushed (first @flush-calls)]
+        (t/testing "exactly one batch upload"
+          (t/is (= 1 (count @flush-calls))))
+        (t/testing "caller opts pass through"
+          (t/is (= opts (:opts flushed))))
+        (t/testing "shapes follow snapshot upload order"
+          (t/is (= (mapv :id expected) (mapv :id (:shapes flushed)))))
+        (t/testing "prepared vector returns in order"
+          (t/is (= (mapv :id expected) (mapv :id result)))))
+      (finally
+        (set! upload/flush-shapes-batch! orig-flush)))))