diff --git a/surfsense_backend/tests/e2e/fakes/embeddings.py b/surfsense_backend/tests/e2e/fakes/embeddings.py
index ab9e24df9..9a01fb84b 100644
--- a/surfsense_backend/tests/e2e/fakes/embeddings.py
+++ b/surfsense_backend/tests/e2e/fakes/embeddings.py
@@ -57,9 +57,9 @@ def install(patches: list[Any]) -> None:
         # Consumers that did `from app.utils.document_converters import embed_text/texts`
         ("app.indexing_pipeline.document_embedder.embed_text", fake_embed_text),
         ("app.indexing_pipeline.document_embedder.embed_texts", fake_embed_texts),
-        # Pipeline service binding (the actual call site for indexing.index)
+        # Index-cache facade binding (the actual call site for indexing.index)
         (
-            "app.indexing_pipeline.indexing_pipeline_service.embed_texts",
+            "app.indexing_pipeline.cache.cached_indexing.embed_texts",
             fake_embed_texts,
         ),
     ]
diff --git a/surfsense_backend/tests/integration/conftest.py b/surfsense_backend/tests/integration/conftest.py
index 19f8e3d0a..8457047ec 100644
--- a/surfsense_backend/tests/integration/conftest.py
+++ b/surfsense_backend/tests/integration/conftest.py
@@ -127,7 +127,7 @@ async def db_search_space(db_session: AsyncSession, db_user: User) -> SearchSpac
 def patched_embed_texts(monkeypatch) -> MagicMock:
     mock = MagicMock(side_effect=lambda texts: [[0.1] * _EMBEDDING_DIM for _ in texts])
     monkeypatch.setattr(
-        "app.indexing_pipeline.indexing_pipeline_service.embed_texts",
+        "app.indexing_pipeline.cache.cached_indexing.embed_texts",
         mock,
     )
     return mock
@@ -137,7 +137,7 @@ def patched_embed_texts(monkeypatch) -> MagicMock:
 def patched_embed_texts_raises(monkeypatch) -> MagicMock:
     mock = MagicMock(side_effect=RuntimeError("Embedding unavailable"))
     monkeypatch.setattr(
-        "app.indexing_pipeline.indexing_pipeline_service.embed_texts",
+        "app.indexing_pipeline.cache.cached_indexing.embed_texts",
         mock,
     )
     return mock
@@ -147,11 +147,11 @@ def patched_embed_texts_raises(monkeypatch) -> MagicMock:
 def patched_chunk_text(monkeypatch) -> MagicMock:
     mock = MagicMock(return_value=["Test chunk content."])
     monkeypatch.setattr(
-        "app.indexing_pipeline.indexing_pipeline_service.chunk_text",
+        "app.indexing_pipeline.cache.cached_indexing.chunk_text",
         mock,
     )
     monkeypatch.setattr(
-        "app.indexing_pipeline.indexing_pipeline_service.chunk_text_hybrid",
+        "app.indexing_pipeline.cache.cached_indexing.chunk_text_hybrid",
         mock,
     )
     return mock
diff --git a/surfsense_backend/tests/integration/document_upload/conftest.py b/surfsense_backend/tests/integration/document_upload/conftest.py
index 812140be3..bd889360f 100644
--- a/surfsense_backend/tests/integration/document_upload/conftest.py
+++ b/surfsense_backend/tests/integration/document_upload/conftest.py
@@ -283,11 +283,11 @@ async def credits():
 def _mock_external_apis(monkeypatch):
     """Mock LLM, embedding, and chunking — these are external API boundaries."""
     monkeypatch.setattr(
-        "app.indexing_pipeline.indexing_pipeline_service.embed_texts",
+        "app.indexing_pipeline.cache.cached_indexing.embed_texts",
         MagicMock(side_effect=lambda texts: [[0.1] * _EMBEDDING_DIM for _ in texts]),
     )
     monkeypatch.setattr(
-        "app.indexing_pipeline.indexing_pipeline_service.chunk_text",
+        "app.indexing_pipeline.cache.cached_indexing.chunk_text",
         MagicMock(return_value=["Test chunk content."]),
     )
 
diff --git a/surfsense_backend/tests/integration/indexing_pipeline/adapters/test_file_upload_adapter.py b/surfsense_backend/tests/integration/indexing_pipeline/adapters/test_file_upload_adapter.py
index 311716052..814129c8d 100644
--- a/surfsense_backend/tests/integration/indexing_pipeline/adapters/test_file_upload_adapter.py
+++ b/surfsense_backend/tests/integration/indexing_pipeline/adapters/test_file_upload_adapter.py
@@ -177,7 +177,7 @@ async def test_reindex_sets_status_ready(db_session, db_search_space, db_user, m
 async def test_reindex_replaces_chunks(db_session, db_search_space, db_user, mocker):
     """Reindexing replaces old chunks with new content rather than appending."""
     mocker.patch(
-        "app.indexing_pipeline.indexing_pipeline_service.chunk_text_hybrid",
+        "app.indexing_pipeline.cache.cached_indexing.chunk_text_hybrid",
         side_effect=[["Original chunk."], ["Updated chunk."]],
     )
 
diff --git a/surfsense_backend/tests/unit/indexing_pipeline/cache/conftest.py b/surfsense_backend/tests/unit/indexing_pipeline/cache/conftest.py
new file mode 100644
index 000000000..081dddaa7
--- /dev/null
+++ b/surfsense_backend/tests/unit/indexing_pipeline/cache/conftest.py
@@ -0,0 +1,28 @@
+"""Stub the cache package __init__s so unit tests import only pure leaf modules.
+
+The real ``cache``/``storage``/``eviction``/``persistence`` __init__s eagerly
+import the facade, file storage, Celery, and ``app.db`` -- none of which a pure
+unit test should need. Turning those packages into bare namespace packages lets
+``from app.indexing_pipeline.cache.<leaf> import ...`` resolve the leaf module
+without running the heavy __init__. ``schemas`` is left real (it is pure).
+"""
+
+import sys
+import types
+from pathlib import Path
+
+_CACHE_DIR = Path(__file__).resolve().parents[4] / "app" / "indexing_pipeline" / "cache"
+
+
+def _stub_namespace_package(dotted: str, fs_dir: Path) -> None:
+    if dotted in sys.modules:
+        return
+    module = types.ModuleType(dotted)
+    module.__path__ = [str(fs_dir)]
+    module.__package__ = dotted
+    sys.modules[dotted] = module
+
+
+_stub_namespace_package("app.indexing_pipeline.cache", _CACHE_DIR)
+_stub_namespace_package("app.indexing_pipeline.cache.storage", _CACHE_DIR / "storage")
+_stub_namespace_package("app.indexing_pipeline.cache.eviction", _CACHE_DIR / "eviction")
diff --git a/surfsense_backend/tests/unit/indexing_pipeline/cache/test_eligibility.py b/surfsense_backend/tests/unit/indexing_pipeline/cache/test_eligibility.py
new file mode 100644
index 000000000..780a6c536
--- /dev/null
+++ b/surfsense_backend/tests/unit/indexing_pipeline/cache/test_eligibility.py
@@ -0,0 +1,28 @@
+from app.indexing_pipeline.cache.eligibility import is_index_cacheable
+
+
+def test_disabled_cache_is_never_cacheable():
+    assert not is_index_cacheable(
+        cache_enabled=False, embedding_model="m", embedding_dim=384
+    )
+
+
+def test_missing_model_is_not_cacheable():
+    assert not is_index_cacheable(
+        cache_enabled=True, embedding_model=None, embedding_dim=384
+    )
+
+
+def test_missing_dimension_is_not_cacheable():
+    assert not is_index_cacheable(
+        cache_enabled=True, embedding_model="m", embedding_dim=None
+    )
+    assert not is_index_cacheable(
+        cache_enabled=True, embedding_model="m", embedding_dim=0
+    )
+
+
+def test_enabled_with_model_and_dim_is_cacheable():
+    assert is_index_cacheable(
+        cache_enabled=True, embedding_model="m", embedding_dim=384
+    )
diff --git a/surfsense_backend/tests/unit/indexing_pipeline/cache/test_embedding_key.py b/surfsense_backend/tests/unit/indexing_pipeline/cache/test_embedding_key.py
new file mode 100644
index 000000000..ce9c8672d
--- /dev/null
+++ b/surfsense_backend/tests/unit/indexing_pipeline/cache/test_embedding_key.py
@@ -0,0 +1,31 @@
+from app.indexing_pipeline.cache.schemas import EmbeddingKey
+
+
+def _key(**overrides) -> EmbeddingKey:
+    base = {
+        "markdown_sha256": "a" * 64,
+        "embedding_model": "openai://text-embedding-3-small",
+        "embedding_dim": 1536,
+        "chunker_kind": "hybrid",
+        "chunker_version": 1,
+    }
+    base.update(overrides)
+    return EmbeddingKey(**base)
+
+
+def test_object_suffix_is_stable():
+    assert _key().object_suffix == _key().object_suffix
+
+
+def test_object_suffix_differs_by_model():
+    assert _key().object_suffix != _key(embedding_model="local/minilm").object_suffix
+
+
+def test_object_suffix_differs_by_chunker_kind_and_version():
+    assert _key().object_suffix != _key(chunker_kind="code").object_suffix
+    assert _key().object_suffix != _key(chunker_version=2).object_suffix
+
+
+def test_object_suffix_encodes_kind_and_version():
+    suffix = _key(chunker_kind="code", chunker_version=3).object_suffix
+    assert suffix.endswith(".code.v3.emb")
diff --git a/surfsense_backend/tests/unit/indexing_pipeline/cache/test_serialization.py b/surfsense_backend/tests/unit/indexing_pipeline/cache/test_serialization.py
new file mode 100644
index 000000000..8db87bf1b
--- /dev/null
+++ b/surfsense_backend/tests/unit/indexing_pipeline/cache/test_serialization.py
@@ -0,0 +1,52 @@
+import numpy as np
+import pytest
+
+from app.indexing_pipeline.cache.schemas import CachedChunk, EmbeddingSet
+from app.indexing_pipeline.cache.serialization import deserialize, serialize
+
+
+def _make_set(dim: int, n_chunks: int) -> EmbeddingSet:
+    rng = np.random.default_rng(0)
+    return EmbeddingSet(
+        summary_embedding=rng.random(dim, dtype=np.float64),
+        chunks=[
+            CachedChunk(text=f"chunk {i}\nwith newline", embedding=rng.random(dim))
+            for i in range(n_chunks)
+        ],
+    )
+
+
+def test_round_trip_preserves_texts_and_vectors():
+    original = _make_set(dim=8, n_chunks=3)
+
+    restored = deserialize(serialize(original))
+
+    assert [c.text for c in restored.chunks] == [c.text for c in original.chunks]
+    assert restored.chunk_count == 3
+    assert np.allclose(restored.summary_embedding, original.summary_embedding, atol=1e-6)
+    for got, want in zip(restored.chunks, original.chunks, strict=True):
+        assert np.allclose(got.embedding, want.embedding, atol=1e-6)
+
+
+def test_round_trip_with_no_chunks():
+    original = _make_set(dim=4, n_chunks=0)
+
+    restored = deserialize(serialize(original))
+
+    assert restored.chunk_count == 0
+    assert restored.summary_embedding.shape[0] == 4
+
+
+def test_serialize_rejects_mismatched_dimensions():
+    bad = EmbeddingSet(
+        summary_embedding=np.zeros(4, dtype=np.float32),
+        chunks=[CachedChunk(text="x", embedding=np.zeros(8, dtype=np.float32))],
+    )
+
+    with pytest.raises(ValueError):
+        serialize(bad)
+
+
+def test_deserialize_rejects_foreign_blob():
+    with pytest.raises(ValueError):
+        deserialize(b"not-a-surfsense-blob")
diff --git a/surfsense_backend/tests/unit/indexing_pipeline/test_index_batch_parallel.py b/surfsense_backend/tests/unit/indexing_pipeline/test_index_batch_parallel.py
index 3a1b77d90..252310061 100644
--- a/surfsense_backend/tests/unit/indexing_pipeline/test_index_batch_parallel.py
+++ b/surfsense_backend/tests/unit/indexing_pipeline/test_index_batch_parallel.py
@@ -54,7 +54,7 @@ async def test_index_calls_embed_and_chunk_via_to_thread(
     mock_chunk_hybrid = MagicMock(return_value=["chunk1"])
     mock_chunk_hybrid.__name__ = "chunk_text_hybrid"
     monkeypatch.setattr(
-        "app.indexing_pipeline.indexing_pipeline_service.chunk_text_hybrid",
+        "app.indexing_pipeline.cache.cached_indexing.chunk_text_hybrid",
         mock_chunk_hybrid,
     )
     mock_embed = MagicMock(
@@ -62,7 +62,7 @@ async def test_index_calls_embed_and_chunk_via_to_thread(
     )
     mock_embed.__name__ = "embed_texts"
     monkeypatch.setattr(
-        "app.indexing_pipeline.indexing_pipeline_service.embed_texts",
+        "app.indexing_pipeline.cache.cached_indexing.embed_texts",
         mock_embed,
     )
     # Bypass set_committed_value, which requires a real ORM instance (not MagicMock).
@@ -102,17 +102,17 @@ async def test_non_code_documents_use_hybrid_chunker(
     mock_chunk_hybrid = MagicMock(return_value=["chunk1"])
     mock_chunk_hybrid.__name__ = "chunk_text_hybrid"
     monkeypatch.setattr(
-        "app.indexing_pipeline.indexing_pipeline_service.chunk_text_hybrid",
+        "app.indexing_pipeline.cache.cached_indexing.chunk_text_hybrid",
         mock_chunk_hybrid,
     )
     mock_chunk_code = MagicMock(return_value=["chunk1"])
     mock_chunk_code.__name__ = "chunk_text"
     monkeypatch.setattr(
-        "app.indexing_pipeline.indexing_pipeline_service.chunk_text",
+        "app.indexing_pipeline.cache.cached_indexing.chunk_text",
         mock_chunk_code,
     )
     monkeypatch.setattr(
-        "app.indexing_pipeline.indexing_pipeline_service.embed_texts",
+        "app.indexing_pipeline.cache.cached_indexing.embed_texts",
         MagicMock(side_effect=lambda texts: [[0.1] * _EMBEDDING_DIM for _ in texts]),
     )
     monkeypatch.setattr(