diff --git a/main.py b/main.py
index 2cbf404..be2ec27 100644
--- a/main.py
+++ b/main.py
@@ -1,4 +1,5 @@
 import asyncio
+import shutil
 import tempfile
 from pathlib import Path
 
@@ -122,7 +123,12 @@ def _save_attachments(uploaded_files, target_dir: Path) -> list[Path]:
         holder = target_dir / str(index)
         holder.mkdir(parents=True, exist_ok=True)
         path = holder / uploaded.name
-        path.write_bytes(uploaded.getvalue())
+        # Потоковое копирование: UploadedFile уже целиком лежит в памяти
+        # Streamlit, а getvalue() делал бы вторую полную копию каждого
+        # вложения перед записью на диск.
+        uploaded.seek(0)
+        with path.open("wb") as target:
+            shutil.copyfileobj(uploaded, target)
         paths.append(path)
     return paths
 
diff --git a/tests/smoke/test_batch_progress.py b/tests/smoke/test_batch_progress.py
new file mode 100644
index 0000000..abf2cb3
--- /dev/null
+++ b/tests/smoke/test_batch_progress.py
@@ -0,0 +1,59 @@
+from __future__ import annotations
+
+import zipfile
+from pathlib import Path
+
+from app.pipeline import service
+from app.pipeline.service import run_batch
+from tests.smoke.test_batch_smoke import _patch_opencloud, _valid_xml
+
+
+def test_progress_callback_is_called_once_per_xml_file(
+    tmp_path: Path, monkeypatch
+) -> None:
+    _patch_opencloud(monkeypatch)
+    zip_path = tmp_path / "batch.zip"
+    names = [f"SKO115FZ_01_123456789_20260616_X0000{i}.xml" for i in range(1, 4)]
+    with zipfile.ZipFile(zip_path, "w") as archive:
+        for name in names:
+            archive.writestr(name, _valid_xml())
+    loose = tmp_path / "SKO115FZ_01_123456789_20260616_X00009.xml"
+    loose.write_text(_valid_xml(), encoding="utf-8")
+
+    calls: list[tuple[int, int, str]] = []
+    result = run_batch(
+        input_paths=[zip_path, loose],
+        launcher="tester",
+        opencloud_username="test-user",
+        opencloud_access_token="token-123",
+        progress_callback=lambda done, total, name: calls.append((done, total, name)),
+    )
+
+    assert result.status == "success"
+    assert [done for done, _, _ in calls] == [1, 2, 3, 4]
+    assert {total for _, total, _ in calls} == {4}
+    assert sorted(name for _, _, name in calls) == sorted([*names, loose.name])
+
+
+def test_progress_callback_is_called_for_unreadable_file_too(
+    tmp_path: Path, monkeypatch
+) -> None:
+    _patch_opencloud(monkeypatch)
+    loose = tmp_path / "SKO115FZ_01_123456789_20260616_X00001.xml"
+    loose.write_text(_valid_xml(), encoding="utf-8")
+
+    def _boom(self: Path) -> bytes:
+        raise OSError("disk gone")
+
+    monkeypatch.setattr(service.Path, "read_bytes", _boom)
+    calls: list[tuple[int, int, str]] = []
+    result = run_batch(
+        input_paths=[loose],
+        launcher="tester",
+        opencloud_username="test-user",
+        opencloud_access_token="token-123",
+        progress_callback=lambda done, total, name: calls.append((done, total, name)),
+    )
+
+    assert result.status == "error"
+    assert calls == [(1, 1, loose.name)]
diff --git a/tests/unit/test_main_attachments.py b/tests/unit/test_main_attachments.py
new file mode 100644
index 0000000..a05c37e
--- /dev/null
+++ b/tests/unit/test_main_attachments.py
@@ -0,0 +1,50 @@
+"""Сохранение вложений Streamlit на диск не должно удваивать их в памяти.
+
+UploadedFile — это BytesIO: Streamlit уже держит всё содержимое вложения в
+памяти. getvalue() делает ещё одну полную копию каждого файла перед записью
+на диск; при 230 вложениях в контейнере на 1 ГБ это лишняя пиковая нагрузка.
+Копировать нужно потоково, через файловый интерфейс, не трогая getvalue().
+"""
+
+from __future__ import annotations
+
+import io
+from pathlib import Path
+
+from main import _save_attachments
+
+
+class _UploadWithoutGetValue(io.BytesIO):
+    """Вложение, у которого есть только файловый интерфейс и имя."""
+
+    def __init__(self, name: str, payload: bytes) -> None:
+        super().__init__(payload)
+        self.name = name
+
+    def getvalue(self) -> bytes:  # type: ignore[override]
+        raise AssertionError("getvalue() копирует всё вложение в память")
+
+
+def test_save_attachments_streams_without_getvalue(tmp_path: Path) -> None:
+    uploads = [
+        _UploadWithoutGetValue("a.xml", b"<a/>"),
+        _UploadWithoutGetValue("a.xml", b"<b/>" * 1000),
+    ]
+
+    paths = _save_attachments(uploads, tmp_path)
+
+    assert [path.name for path in paths] == ["a.xml", "a.xml"]
+    assert paths[0] != paths[1]
+    assert paths[0].read_bytes() == b"<a/>"
+    assert paths[1].read_bytes() == b"<b/>" * 1000
+
+
+def test_save_attachments_copies_from_start_even_if_upload_was_read(
+    tmp_path: Path,
+) -> None:
+    upload = _UploadWithoutGetValue("f.xml", b"0123456789")
+    upload.read(4)
+
+    (path,) = _save_attachments([upload], tmp_path)
+
+    assert path.read_bytes() == b"0123456789"