diff --git a/surfsense_backend/tests/unit/connector_indexers/test_content_extraction.py b/surfsense_backend/tests/unit/connector_indexers/test_content_extraction.py
new file mode 100644
index 000000000..49f9a217a
--- /dev/null
+++ b/surfsense_backend/tests/unit/connector_indexers/test_content_extraction.py
@@ -0,0 +1,244 @@
+"""Tests that each cloud connector's download_and_extract_content correctly
+produces markdown from a real file via the unified ETL pipeline.
+
+Only the cloud client is mocked (system boundary).  The ETL pipeline runs for
+real so we know the full path from "cloud gives us bytes" to "we get markdown
+back" actually works.
+"""
+
+import os
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+
+pytestmark = pytest.mark.unit
+
+_TXT_CONTENT = "Hello from the cloud connector test."
+_CSV_CONTENT = "name,age\nAlice,30\nBob,25\n"
+
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+async def _write_file(dest_path: str, content: str) -> None:
+    """Simulate a cloud client writing downloaded bytes to disk."""
+    with open(dest_path, "w", encoding="utf-8") as f:
+        f.write(content)
+
+
+def _make_download_side_effect(content: str):
+    """Return an async side-effect that writes *content* to the dest path
+    and returns ``None`` (success)."""
+
+    async def _side_effect(*args):
+        dest_path = args[-1]
+        await _write_file(dest_path, content)
+        return None
+
+    return _side_effect
+
+
+# ===================================================================
+# Google Drive
+# ===================================================================
+
+class TestGoogleDriveContentExtraction:
+
+    async def test_txt_file_returns_markdown(self):
+        from app.connectors.google_drive.content_extractor import (
+            download_and_extract_content,
+        )
+
+        client = MagicMock()
+        client.download_file_to_disk = AsyncMock(
+            side_effect=_make_download_side_effect(_TXT_CONTENT),
+        )
+
+        file = {"id": "f1", "name": "notes.txt", "mimeType": "text/plain"}
+
+        markdown, metadata, error = await download_and_extract_content(client, file)
+
+        assert error is None
+        assert _TXT_CONTENT in markdown
+        assert metadata["google_drive_file_id"] == "f1"
+        assert metadata["google_drive_file_name"] == "notes.txt"
+
+    async def test_csv_file_returns_markdown_table(self):
+        from app.connectors.google_drive.content_extractor import (
+            download_and_extract_content,
+        )
+
+        client = MagicMock()
+        client.download_file_to_disk = AsyncMock(
+            side_effect=_make_download_side_effect(_CSV_CONTENT),
+        )
+
+        file = {"id": "f2", "name": "data.csv", "mimeType": "text/csv"}
+
+        markdown, metadata, error = await download_and_extract_content(client, file)
+
+        assert error is None
+        assert "Alice" in markdown
+        assert "Bob" in markdown
+        assert "|" in markdown
+
+    async def test_download_error_returns_error_message(self):
+        from app.connectors.google_drive.content_extractor import (
+            download_and_extract_content,
+        )
+
+        client = MagicMock()
+        client.download_file_to_disk = AsyncMock(return_value="Network timeout")
+
+        file = {"id": "f3", "name": "doc.txt", "mimeType": "text/plain"}
+
+        markdown, metadata, error = await download_and_extract_content(client, file)
+
+        assert markdown is None
+        assert error == "Network timeout"
+
+
+# ===================================================================
+# OneDrive
+# ===================================================================
+
+class TestOneDriveContentExtraction:
+
+    async def test_txt_file_returns_markdown(self):
+        from app.connectors.onedrive.content_extractor import (
+            download_and_extract_content,
+        )
+
+        client = MagicMock()
+        client.download_file_to_disk = AsyncMock(
+            side_effect=_make_download_side_effect(_TXT_CONTENT),
+        )
+
+        file = {
+            "id": "od-1",
+            "name": "report.txt",
+            "file": {"mimeType": "text/plain"},
+        }
+
+        markdown, metadata, error = await download_and_extract_content(client, file)
+
+        assert error is None
+        assert _TXT_CONTENT in markdown
+        assert metadata["onedrive_file_id"] == "od-1"
+        assert metadata["onedrive_file_name"] == "report.txt"
+
+    async def test_csv_file_returns_markdown_table(self):
+        from app.connectors.onedrive.content_extractor import (
+            download_and_extract_content,
+        )
+
+        client = MagicMock()
+        client.download_file_to_disk = AsyncMock(
+            side_effect=_make_download_side_effect(_CSV_CONTENT),
+        )
+
+        file = {
+            "id": "od-2",
+            "name": "data.csv",
+            "file": {"mimeType": "text/csv"},
+        }
+
+        markdown, metadata, error = await download_and_extract_content(client, file)
+
+        assert error is None
+        assert "Alice" in markdown
+        assert "|" in markdown
+
+    async def test_download_error_returns_error_message(self):
+        from app.connectors.onedrive.content_extractor import (
+            download_and_extract_content,
+        )
+
+        client = MagicMock()
+        client.download_file_to_disk = AsyncMock(return_value="403 Forbidden")
+
+        file = {
+            "id": "od-3",
+            "name": "secret.txt",
+            "file": {"mimeType": "text/plain"},
+        }
+
+        markdown, metadata, error = await download_and_extract_content(client, file)
+
+        assert markdown is None
+        assert error == "403 Forbidden"
+
+
+# ===================================================================
+# Dropbox
+# ===================================================================
+
+class TestDropboxContentExtraction:
+
+    async def test_txt_file_returns_markdown(self):
+        from app.connectors.dropbox.content_extractor import (
+            download_and_extract_content,
+        )
+
+        client = MagicMock()
+        client.download_file_to_disk = AsyncMock(
+            side_effect=_make_download_side_effect(_TXT_CONTENT),
+        )
+
+        file = {
+            "id": "dbx-1",
+            "name": "memo.txt",
+            ".tag": "file",
+            "path_lower": "/memo.txt",
+        }
+
+        markdown, metadata, error = await download_and_extract_content(client, file)
+
+        assert error is None
+        assert _TXT_CONTENT in markdown
+        assert metadata["dropbox_file_id"] == "dbx-1"
+        assert metadata["dropbox_file_name"] == "memo.txt"
+
+    async def test_csv_file_returns_markdown_table(self):
+        from app.connectors.dropbox.content_extractor import (
+            download_and_extract_content,
+        )
+
+        client = MagicMock()
+        client.download_file_to_disk = AsyncMock(
+            side_effect=_make_download_side_effect(_CSV_CONTENT),
+        )
+
+        file = {
+            "id": "dbx-2",
+            "name": "data.csv",
+            ".tag": "file",
+            "path_lower": "/data.csv",
+        }
+
+        markdown, metadata, error = await download_and_extract_content(client, file)
+
+        assert error is None
+        assert "Alice" in markdown
+        assert "|" in markdown
+
+    async def test_download_error_returns_error_message(self):
+        from app.connectors.dropbox.content_extractor import (
+            download_and_extract_content,
+        )
+
+        client = MagicMock()
+        client.download_file_to_disk = AsyncMock(return_value="Rate limited")
+
+        file = {
+            "id": "dbx-3",
+            "name": "big.txt",
+            ".tag": "file",
+            "path_lower": "/big.txt",
+        }
+
+        markdown, metadata, error = await download_and_extract_content(client, file)
+
+        assert markdown is None
+        assert error == "Rate limited"
diff --git a/surfsense_backend/tests/unit/etl_pipeline/conftest.py b/surfsense_backend/tests/unit/etl_pipeline/conftest.py
new file mode 100644
index 000000000..6059caa01
--- /dev/null
+++ b/surfsense_backend/tests/unit/etl_pipeline/conftest.py
@@ -0,0 +1,29 @@
+"""Pre-register the etl_pipeline package to avoid circular imports during unit tests."""
+
+import sys
+import types
+from pathlib import Path
+
+_BACKEND = Path(__file__).resolve().parents[3]
+
+
+def _stub_package(dotted: str, fs_dir: Path) -> None:
+    if dotted not in sys.modules:
+        mod = types.ModuleType(dotted)
+        mod.__path__ = [str(fs_dir)]
+        mod.__package__ = dotted
+        sys.modules[dotted] = mod
+
+    parts = dotted.split(".")
+    if len(parts) > 1:
+        parent_dotted = ".".join(parts[:-1])
+        parent = sys.modules.get(parent_dotted)
+        if parent is not None:
+            setattr(parent, parts[-1], sys.modules[dotted])
+
+
+_stub_package("app", _BACKEND / "app")
+_stub_package("app.etl_pipeline", _BACKEND / "app" / "etl_pipeline")
+_stub_package(
+    "app.etl_pipeline.parsers", _BACKEND / "app" / "etl_pipeline" / "parsers"
+)
diff --git a/surfsense_backend/tests/unit/etl_pipeline/test_etl_pipeline_service.py b/surfsense_backend/tests/unit/etl_pipeline/test_etl_pipeline_service.py
new file mode 100644
index 000000000..0d31507ca
--- /dev/null
+++ b/surfsense_backend/tests/unit/etl_pipeline/test_etl_pipeline_service.py
@@ -0,0 +1,309 @@
+"""Tests for EtlPipelineService -- the unified ETL pipeline public interface."""
+
+import pytest
+
+from app.etl_pipeline.etl_document import EtlRequest
+from app.etl_pipeline.etl_pipeline_service import EtlPipelineService
+
+pytestmark = pytest.mark.unit
+
+
+async def test_extract_txt_file_returns_markdown(tmp_path):
+    """Tracer bullet: a .txt file is read and returned as-is in an EtlResult."""
+    txt_file = tmp_path / "hello.txt"
+    txt_file.write_text("Hello, world!", encoding="utf-8")
+
+    service = EtlPipelineService()
+    result = await service.extract(
+        EtlRequest(file_path=str(txt_file), filename="hello.txt")
+    )
+
+    assert result.markdown_content == "Hello, world!"
+    assert result.etl_service == "PLAINTEXT"
+    assert result.content_type == "plaintext"
+
+
+async def test_extract_md_file(tmp_path):
+    """A .md file is classified as PLAINTEXT and extracted."""
+    md_file = tmp_path / "readme.md"
+    md_file.write_text("# Title\n\nBody text.", encoding="utf-8")
+
+    result = await EtlPipelineService().extract(
+        EtlRequest(file_path=str(md_file), filename="readme.md")
+    )
+
+    assert result.markdown_content == "# Title\n\nBody text."
+    assert result.etl_service == "PLAINTEXT"
+    assert result.content_type == "plaintext"
+
+
+async def test_extract_markdown_file(tmp_path):
+    """A .markdown file is classified as PLAINTEXT and extracted."""
+    md_file = tmp_path / "notes.markdown"
+    md_file.write_text("Some notes.", encoding="utf-8")
+
+    result = await EtlPipelineService().extract(
+        EtlRequest(file_path=str(md_file), filename="notes.markdown")
+    )
+
+    assert result.markdown_content == "Some notes."
+    assert result.etl_service == "PLAINTEXT"
+
+
+async def test_extract_python_file(tmp_path):
+    """A .py source code file is classified as PLAINTEXT."""
+    py_file = tmp_path / "script.py"
+    py_file.write_text("print('hello')", encoding="utf-8")
+
+    result = await EtlPipelineService().extract(
+        EtlRequest(file_path=str(py_file), filename="script.py")
+    )
+
+    assert result.markdown_content == "print('hello')"
+    assert result.etl_service == "PLAINTEXT"
+    assert result.content_type == "plaintext"
+
+
+async def test_extract_js_file(tmp_path):
+    """A .js source code file is classified as PLAINTEXT."""
+    js_file = tmp_path / "app.js"
+    js_file.write_text("console.log('hi');", encoding="utf-8")
+
+    result = await EtlPipelineService().extract(
+        EtlRequest(file_path=str(js_file), filename="app.js")
+    )
+
+    assert result.markdown_content == "console.log('hi');"
+    assert result.etl_service == "PLAINTEXT"
+
+
+async def test_extract_csv_returns_markdown_table(tmp_path):
+    """A .csv file is converted to a markdown table."""
+    csv_file = tmp_path / "data.csv"
+    csv_file.write_text("name,age\nAlice,30\nBob,25\n", encoding="utf-8")
+
+    result = await EtlPipelineService().extract(
+        EtlRequest(file_path=str(csv_file), filename="data.csv")
+    )
+
+    assert "| name | age |" in result.markdown_content
+    assert "| Alice | 30 |" in result.markdown_content
+    assert result.etl_service == "DIRECT_CONVERT"
+    assert result.content_type == "direct_convert"
+
+
+async def test_extract_tsv_returns_markdown_table(tmp_path):
+    """A .tsv file is converted to a markdown table."""
+    tsv_file = tmp_path / "data.tsv"
+    tsv_file.write_text("x\ty\n1\t2\n", encoding="utf-8")
+
+    result = await EtlPipelineService().extract(
+        EtlRequest(file_path=str(tsv_file), filename="data.tsv")
+    )
+
+    assert "| x | y |" in result.markdown_content
+    assert result.etl_service == "DIRECT_CONVERT"
+
+
+async def test_extract_html_returns_markdown(tmp_path):
+    """An .html file is converted to markdown."""
+    html_file = tmp_path / "page.html"
+    html_file.write_text("<h1>Title</h1><p>Body</p>", encoding="utf-8")
+
+    result = await EtlPipelineService().extract(
+        EtlRequest(file_path=str(html_file), filename="page.html")
+    )
+
+    assert "Title" in result.markdown_content
+    assert "Body" in result.markdown_content
+    assert result.etl_service == "DIRECT_CONVERT"
+
+
+async def test_extract_mp3_returns_transcription(tmp_path, mocker):
+    """An .mp3 audio file is transcribed via litellm.atranscription."""
+    audio_file = tmp_path / "recording.mp3"
+    audio_file.write_bytes(b"\x00" * 100)
+
+    mocker.patch("app.config.config.STT_SERVICE", "openai/whisper-1")
+    mocker.patch("app.config.config.STT_SERVICE_API_KEY", "fake-key")
+    mocker.patch("app.config.config.STT_SERVICE_API_BASE", None)
+
+    mock_transcription = mocker.patch(
+        "app.etl_pipeline.parsers.audio.atranscription",
+        return_value={"text": "Hello from audio"},
+    )
+
+    result = await EtlPipelineService().extract(
+        EtlRequest(file_path=str(audio_file), filename="recording.mp3")
+    )
+
+    assert "Hello from audio" in result.markdown_content
+    assert result.etl_service == "AUDIO"
+    assert result.content_type == "audio"
+    mock_transcription.assert_called_once()
+
+
+# ---------------------------------------------------------------------------
+# Slice 7 – DOCLING document parsing
+# ---------------------------------------------------------------------------
+
+
+async def test_extract_pdf_with_docling(tmp_path, mocker):
+    """A .pdf file with ETL_SERVICE=DOCLING returns parsed markdown."""
+    pdf_file = tmp_path / "report.pdf"
+    pdf_file.write_bytes(b"%PDF-1.4 fake")
+
+    mocker.patch("app.config.config.ETL_SERVICE", "DOCLING")
+
+    fake_docling = mocker.AsyncMock()
+    fake_docling.process_document.return_value = {"content": "# Parsed PDF"}
+    mocker.patch(
+        "app.services.docling_service.create_docling_service",
+        return_value=fake_docling,
+    )
+
+    result = await EtlPipelineService().extract(
+        EtlRequest(file_path=str(pdf_file), filename="report.pdf")
+    )
+
+    assert result.markdown_content == "# Parsed PDF"
+    assert result.etl_service == "DOCLING"
+    assert result.content_type == "document"
+
+
+# ---------------------------------------------------------------------------
+# Slice 8 – UNSTRUCTURED document parsing
+# ---------------------------------------------------------------------------
+
+
+async def test_extract_pdf_with_unstructured(tmp_path, mocker):
+    """A .pdf file with ETL_SERVICE=UNSTRUCTURED returns parsed markdown."""
+    pdf_file = tmp_path / "report.pdf"
+    pdf_file.write_bytes(b"%PDF-1.4 fake")
+
+    mocker.patch("app.config.config.ETL_SERVICE", "UNSTRUCTURED")
+
+    class FakeDoc:
+        def __init__(self, text):
+            self.page_content = text
+
+    fake_loader_instance = mocker.AsyncMock()
+    fake_loader_instance.aload.return_value = [
+        FakeDoc("Page 1 content"),
+        FakeDoc("Page 2 content"),
+    ]
+    mocker.patch(
+        "langchain_unstructured.UnstructuredLoader",
+        return_value=fake_loader_instance,
+    )
+
+    result = await EtlPipelineService().extract(
+        EtlRequest(file_path=str(pdf_file), filename="report.pdf")
+    )
+
+    assert "Page 1 content" in result.markdown_content
+    assert "Page 2 content" in result.markdown_content
+    assert result.etl_service == "UNSTRUCTURED"
+    assert result.content_type == "document"
+
+
+# ---------------------------------------------------------------------------
+# Slice 9 – LLAMACLOUD document parsing
+# ---------------------------------------------------------------------------
+
+
+async def test_extract_pdf_with_llamacloud(tmp_path, mocker):
+    """A .pdf file with ETL_SERVICE=LLAMACLOUD returns parsed markdown."""
+    pdf_file = tmp_path / "report.pdf"
+    pdf_file.write_bytes(b"%PDF-1.4 fake content " * 10)
+
+    mocker.patch("app.config.config.ETL_SERVICE", "LLAMACLOUD")
+    mocker.patch("app.config.config.LLAMA_CLOUD_API_KEY", "fake-key", create=True)
+
+    class FakeDoc:
+        text = "# LlamaCloud parsed"
+
+    class FakeJobResult:
+        pages = []
+
+        def get_markdown_documents(self, split_by_page=True):
+            return [FakeDoc()]
+
+    fake_parser = mocker.AsyncMock()
+    fake_parser.aparse.return_value = FakeJobResult()
+    mocker.patch(
+        "llama_cloud_services.LlamaParse",
+        return_value=fake_parser,
+    )
+    mocker.patch(
+        "llama_cloud_services.parse.utils.ResultType",
+        mocker.MagicMock(MD="md"),
+    )
+
+    result = await EtlPipelineService().extract(
+        EtlRequest(
+            file_path=str(pdf_file), filename="report.pdf", estimated_pages=5
+        )
+    )
+
+    assert result.markdown_content == "# LlamaCloud parsed"
+    assert result.etl_service == "LLAMACLOUD"
+    assert result.content_type == "document"
+
+
+# ---------------------------------------------------------------------------
+# Slice 10 – unknown extension falls through to document ETL
+# ---------------------------------------------------------------------------
+
+
+async def test_unknown_extension_uses_document_etl(tmp_path, mocker):
+    """An unknown extension (e.g. .docx) falls through to the document ETL path."""
+    docx_file = tmp_path / "doc.docx"
+    docx_file.write_bytes(b"PK fake docx")
+
+    mocker.patch("app.config.config.ETL_SERVICE", "DOCLING")
+
+    fake_docling = mocker.AsyncMock()
+    fake_docling.process_document.return_value = {"content": "Docx content"}
+    mocker.patch(
+        "app.services.docling_service.create_docling_service",
+        return_value=fake_docling,
+    )
+
+    result = await EtlPipelineService().extract(
+        EtlRequest(file_path=str(docx_file), filename="doc.docx")
+    )
+
+    assert result.markdown_content == "Docx content"
+    assert result.content_type == "document"
+
+
+# ---------------------------------------------------------------------------
+# Slice 11 – EtlRequest validation
+# ---------------------------------------------------------------------------
+
+
+def test_etl_request_requires_filename():
+    """EtlRequest rejects missing filename."""
+    with pytest.raises(Exception):
+        EtlRequest(file_path="/tmp/some.txt", filename="")
+
+
+# ---------------------------------------------------------------------------
+# Slice 12 – unknown ETL_SERVICE raises EtlServiceUnavailableError
+# ---------------------------------------------------------------------------
+
+
+async def test_unknown_etl_service_raises(tmp_path, mocker):
+    """An unknown ETL_SERVICE raises EtlServiceUnavailableError."""
+    from app.etl_pipeline.exceptions import EtlServiceUnavailableError
+
+    pdf_file = tmp_path / "report.pdf"
+    pdf_file.write_bytes(b"%PDF fake")
+
+    mocker.patch("app.config.config.ETL_SERVICE", "NONEXISTENT")
+
+    with pytest.raises(EtlServiceUnavailableError, match="Unknown ETL_SERVICE"):
+        await EtlPipelineService().extract(
+            EtlRequest(file_path=str(pdf_file), filename="report.pdf")
+        )