diff --git a/app/api/assets_routes.py b/app/api/assets_routes.py
index 252242eae..001dfa324 100644
--- a/app/api/assets_routes.py
+++ b/app/api/assets_routes.py
@@ -283,7 +283,7 @@ async def upload_asset(request: web.Request) -> web.Response:
                 "Uploaded file hash does not match provided hash.",
             )
         return _error_response(400, "BAD_REQUEST", "Invalid inputs.")
-    except Exception as e:
+    except Exception:
         if tmp_path and os.path.exists(tmp_path):
             os.remove(tmp_path)
         return _error_response(500, "INTERNAL", "Unexpected server error.")
diff --git a/app/database/_helpers.py b/app/database/_helpers.py
index 5ce972076..a031e861c 100644
--- a/app/database/_helpers.py
+++ b/app/database/_helpers.py
@@ -67,32 +67,29 @@ def apply_metadata_filter(
         return stmt
 
     def _exists_for_pred(key: str, *preds) -> sa.sql.ClauseElement:
-        subquery = (
-            select(sa.literal(1))
-            .select_from(AssetInfoMeta)
-            .where(
-                AssetInfoMeta.asset_info_id == AssetInfo.id,
-                AssetInfoMeta.key == key,
-                *preds,
-            )
-            .limit(1)
+        return sa.exists().where(
+            AssetInfoMeta.asset_info_id == AssetInfo.id,
+            AssetInfoMeta.key == key,
+            *preds,
         )
-        return sa.exists(subquery)
 
     def _exists_clause_for_value(key: str, value) -> sa.sql.ClauseElement:
         # Missing OR null:
         if value is None:
             # either: no row for key OR a row for key with explicit null
-            no_row_for_key = ~sa.exists(
-                select(sa.literal(1))
-                .select_from(AssetInfoMeta)
-                .where(
+            no_row_for_key = sa.not_(
+                sa.exists().where(
                     AssetInfoMeta.asset_info_id == AssetInfo.id,
                     AssetInfoMeta.key == key,
                 )
-                .limit(1)
             )
-            null_row = _exists_for_pred(key, AssetInfoMeta.val_json.is_(None))
+            null_row = _exists_for_pred(
+                key,
+                AssetInfoMeta.val_json.is_(None),
+                AssetInfoMeta.val_str.is_(None),
+                AssetInfoMeta.val_num.is_(None),
+                AssetInfoMeta.val_bool.is_(None),
+            )
             return sa.or_(no_row_for_key, null_row)
 
         # Typed scalar matches:
@@ -135,13 +132,19 @@ def project_kv(key: str, value: Any) -> list[dict]:
     - scalar -> one row (ordinal=0) in the proper typed column
     - list of scalars -> one row per element with ordinal=i
     - dict or list with non-scalars -> single row with val_json (or one per element w/ val_json if list)
-    - None -> single row with val_json = None
+    - None -> single row with all value columns NULL
     Each row: {"key": key, "ordinal": i, "val_str"/"val_num"/"val_bool"/"val_json": ...}
     """
     rows: list[dict] = []
 
+    def _null_row(ordinal: int) -> dict:
+        return {
+            "key": key, "ordinal": ordinal,
+            "val_str": None, "val_num": None, "val_bool": None, "val_json": None
+        }
+
     if value is None:
-        rows.append({"key": key, "ordinal": 0, "val_json": None})
+        rows.append(_null_row(0))
         return rows
 
     if is_scalar(value):
@@ -162,7 +165,7 @@ def project_kv(key: str, value: Any) -> list[dict]:
         if all(is_scalar(x) for x in value):
             for i, x in enumerate(value):
                 if x is None:
-                    rows.append({"key": key, "ordinal": i, "val_json": None})
+                    rows.append(_null_row(i))
                 elif isinstance(x, bool):
                     rows.append({"key": key, "ordinal": i, "val_bool": bool(x)})
                 elif isinstance(x, (int, float, Decimal)):
diff --git a/app/database/models.py b/app/database/models.py
index 203867468..5bb3a09bc 100644
--- a/app/database/models.py
+++ b/app/database/models.py
@@ -145,7 +145,7 @@ class AssetInfo(Base):
         String(256), ForeignKey("assets.hash", ondelete="RESTRICT"), nullable=False
     )
     preview_hash: Mapped[str | None] = mapped_column(String(256), ForeignKey("assets.hash", ondelete="SET NULL"))
-    user_metadata: Mapped[dict[str, Any] | None] = mapped_column(JSON)
+    user_metadata: Mapped[dict[str, Any] | None] = mapped_column(JSON(none_as_null=True))
     created_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=False), nullable=False, default=utcnow
     )
@@ -220,7 +220,7 @@ class AssetInfoMeta(Base):
     val_str: Mapped[Optional[str]] = mapped_column(String(2048), nullable=True)
     val_num: Mapped[Optional[float]] = mapped_column(Numeric(38, 10), nullable=True)
     val_bool: Mapped[Optional[bool]] = mapped_column(Boolean, nullable=True)
-    val_json: Mapped[Optional[Any]] = mapped_column(JSON, nullable=True)
+    val_json: Mapped[Optional[Any]] = mapped_column(JSON(none_as_null=True), nullable=True)
 
     asset_info: Mapped["AssetInfo"] = relationship(back_populates="metadata_entries")
 
diff --git a/tests-assets/test_metadata_filters.py b/tests-assets/test_metadata_filters.py
new file mode 100644
index 000000000..39d00fa2d
--- /dev/null
+++ b/tests-assets/test_metadata_filters.py
@@ -0,0 +1,378 @@
+import json
+import aiohttp
+import pytest
+
+
+@pytest.mark.asyncio
+async def test_meta_and_across_keys_and_types(http: aiohttp.ClientSession, api_base: str, asset_factory, make_asset_bytes):
+    name = "mf_and_mix.safetensors"
+    tags = ["models", "checkpoints", "unit-tests", "mf-and"]
+    meta = {"purpose": "mix", "epoch": 1, "active": True, "score": 1.23}
+    await asset_factory(name, tags, meta, make_asset_bytes(name, 4096))
+
+    # All keys must match (AND semantics)
+    f_ok = {"purpose": "mix", "epoch": 1, "active": True, "score": 1.23}
+    async with http.get(
+        api_base + "/api/assets",
+        params={
+            "include_tags": "unit-tests,mf-and",
+            "metadata_filter": json.dumps(f_ok),
+        },
+    ) as r1:
+        b1 = await r1.json()
+        assert r1.status == 200
+        names = [a["name"] for a in b1["assets"]]
+        assert name in names
+
+    # One key mismatched -> no result
+    f_bad = {"purpose": "mix", "epoch": 2, "active": True}
+    async with http.get(
+        api_base + "/api/assets",
+        params={
+            "include_tags": "unit-tests,mf-and",
+            "metadata_filter": json.dumps(f_bad),
+        },
+    ) as r2:
+        b2 = await r2.json()
+        assert r2.status == 200
+        assert not b2["assets"]
+
+
+@pytest.mark.asyncio
+async def test_meta_type_strictness_int_vs_str_and_bool(http, api_base, asset_factory, make_asset_bytes):
+    name = "mf_types.safetensors"
+    tags = ["models", "checkpoints", "unit-tests", "mf-types"]
+    meta = {"epoch": 1, "active": True}
+    await asset_factory(name, tags, meta, make_asset_bytes(name))
+
+    # int filter matches numeric
+    async with http.get(
+        api_base + "/api/assets",
+        params={
+            "include_tags": "unit-tests,mf-types",
+            "metadata_filter": json.dumps({"epoch": 1}),
+        },
+    ) as r1:
+        b1 = await r1.json()
+        assert r1.status == 200 and any(a["name"] == name for a in b1["assets"])
+
+    # string "1" must NOT match numeric 1
+    async with http.get(
+        api_base + "/api/assets",
+        params={
+            "include_tags": "unit-tests,mf-types",
+            "metadata_filter": json.dumps({"epoch": "1"}),
+        },
+    ) as r2:
+        b2 = await r2.json()
+        assert r2.status == 200 and not b2["assets"]
+
+    # bool True matches, string "true" must NOT match
+    async with http.get(
+        api_base + "/api/assets",
+        params={
+            "include_tags": "unit-tests,mf-types",
+            "metadata_filter": json.dumps({"active": True}),
+        },
+    ) as r3:
+        b3 = await r3.json()
+        assert r3.status == 200 and any(a["name"] == name for a in b3["assets"])
+
+    async with http.get(
+        api_base + "/api/assets",
+        params={
+            "include_tags": "unit-tests,mf-types",
+            "metadata_filter": json.dumps({"active": "true"}),
+        },
+    ) as r4:
+        b4 = await r4.json()
+        assert r4.status == 200 and not b4["assets"]
+
+
+@pytest.mark.asyncio
+async def test_meta_any_of_list_of_scalars(http, api_base, asset_factory, make_asset_bytes):
+    name = "mf_list_scalars.safetensors"
+    tags = ["models", "checkpoints", "unit-tests", "mf-list"]
+    meta = {"flags": ["red", "green"]}
+    await asset_factory(name, tags, meta, make_asset_bytes(name, 3000))
+
+    # Any-of should match because "green" is present
+    filt_ok = {"flags": ["blue", "green"]}
+    async with http.get(
+        api_base + "/api/assets",
+        params={"include_tags": "unit-tests,mf-list", "metadata_filter": json.dumps(filt_ok)},
+    ) as r1:
+        b1 = await r1.json()
+        assert r1.status == 200 and any(a["name"] == name for a in b1["assets"])
+
+    # None of provided flags present -> no match
+    filt_miss = {"flags": ["blue", "yellow"]}
+    async with http.get(
+        api_base + "/api/assets",
+        params={"include_tags": "unit-tests,mf-list", "metadata_filter": json.dumps(filt_miss)},
+    ) as r2:
+        b2 = await r2.json()
+        assert r2.status == 200 and not b2["assets"]
+
+    # Duplicates in list should not break matching
+    filt_dup = {"flags": ["green", "green", "green"]}
+    async with http.get(
+        api_base + "/api/assets",
+        params={"include_tags": "unit-tests,mf-list", "metadata_filter": json.dumps(filt_dup)},
+    ) as r3:
+        b3 = await r3.json()
+        assert r3.status == 200 and any(a["name"] == name for a in b3["assets"])
+
+
+@pytest.mark.asyncio
+async def test_meta_none_semantics_missing_or_null_and_any_of_with_none(http, api_base, asset_factory, make_asset_bytes):
+    # a1: key missing; a2: explicit null; a3: concrete value
+    t = ["models", "checkpoints", "unit-tests", "mf-none"]
+    a1 = await asset_factory("mf_none_missing.safetensors", t, {"x": 1}, make_asset_bytes("a1"))
+    a2 = await asset_factory("mf_none_null.safetensors", t, {"maybe": None}, make_asset_bytes("a2"))
+    a3 = await asset_factory("mf_none_value.safetensors", t, {"maybe": "x"}, make_asset_bytes("a3"))
+
+    # Filter {maybe: None} must match a1 and a2, not a3
+    filt = {"maybe": None}
+    async with http.get(
+        api_base + "/api/assets",
+        params={"include_tags": "unit-tests,mf-none", "metadata_filter": json.dumps(filt), "sort": "name"},
+    ) as r1:
+        b1 = await r1.json()
+        assert r1.status == 200
+        got = [a["name"] for a in b1["assets"]]
+        assert a1["name"] in got and a2["name"] in got and a3["name"] not in got
+
+    # Any-of with None should include missing/null plus value matches
+    filt_any = {"maybe": [None, "x"]}
+    async with http.get(
+        api_base + "/api/assets",
+        params={"include_tags": "unit-tests,mf-none", "metadata_filter": json.dumps(filt_any), "sort": "name"},
+    ) as r2:
+        b2 = await r2.json()
+        assert r2.status == 200
+        got2 = [a["name"] for a in b2["assets"]]
+        assert a1["name"] in got2 and a2["name"] in got2 and a3["name"] in got2
+
+
+@pytest.mark.asyncio
+async def test_meta_nested_json_object_equality(http, api_base, asset_factory, make_asset_bytes):
+    name = "mf_nested_json.safetensors"
+    tags = ["models", "checkpoints", "unit-tests", "mf-nested"]
+    cfg = {"optimizer": "adam", "lr": 0.001, "schedule": {"type": "cosine", "warmup": 100}}
+    await asset_factory(name, tags, {"config": cfg}, make_asset_bytes(name, 2200))
+
+    # Exact JSON object equality (same structure)
+    async with http.get(
+        api_base + "/api/assets",
+        params={
+            "include_tags": "unit-tests,mf-nested",
+            "metadata_filter": json.dumps({"config": cfg}),
+        },
+    ) as r1:
+        b1 = await r1.json()
+        assert r1.status == 200 and any(a["name"] == name for a in b1["assets"])
+
+    # Different JSON object should not match
+    async with http.get(
+        api_base + "/api/assets",
+        params={
+            "include_tags": "unit-tests,mf-nested",
+            "metadata_filter": json.dumps({"config": {"optimizer": "sgd"}}),
+        },
+    ) as r2:
+        b2 = await r2.json()
+        assert r2.status == 200 and not b2["assets"]
+
+
+@pytest.mark.asyncio
+async def test_meta_list_of_objects_any_of(http, api_base, asset_factory, make_asset_bytes):
+    name = "mf_list_objects.safetensors"
+    tags = ["models", "checkpoints", "unit-tests", "mf-objlist"]
+    transforms = [{"type": "crop", "size": 128}, {"type": "flip", "p": 0.5}]
+    await asset_factory(name, tags, {"transforms": transforms}, make_asset_bytes(name, 2048))
+
+    # Any-of for list of objects should match when one element equals the filter object
+    async with http.get(
+        api_base + "/api/assets",
+        params={
+            "include_tags": "unit-tests,mf-objlist",
+            "metadata_filter": json.dumps({"transforms": {"type": "flip", "p": 0.5}}),
+        },
+    ) as r1:
+        b1 = await r1.json()
+        assert r1.status == 200 and any(a["name"] == name for a in b1["assets"])
+
+    # Non-matching object -> no match
+    async with http.get(
+        api_base + "/api/assets",
+        params={
+            "include_tags": "unit-tests,mf-objlist",
+            "metadata_filter": json.dumps({"transforms": {"type": "rotate", "deg": 90}}),
+        },
+    ) as r2:
+        b2 = await r2.json()
+        assert r2.status == 200 and not b2["assets"]
+
+
+@pytest.mark.asyncio
+async def test_meta_with_special_and_unicode_keys(http, api_base, asset_factory, make_asset_bytes):
+    name = "mf_keys_unicode.safetensors"
+    tags = ["models", "checkpoints", "unit-tests", "mf-keys"]
+    meta = {
+        "weird.key": "v1",
+        "path/like": 7,
+        "with:colon": True,
+        "ключ": "значение",
+        "emoji": "🐍",
+    }
+    await asset_factory(name, tags, meta, make_asset_bytes(name, 1500))
+
+    # Match all the special keys
+    filt = {"weird.key": "v1", "path/like": 7, "with:colon": True, "emoji": "🐍"}
+    async with http.get(
+        api_base + "/api/assets",
+        params={"include_tags": "unit-tests,mf-keys", "metadata_filter": json.dumps(filt)},
+    ) as r1:
+        b1 = await r1.json()
+        assert r1.status == 200 and any(a["name"] == name for a in b1["assets"])
+
+    # Unicode key match
+    async with http.get(
+        api_base + "/api/assets",
+        params={"include_tags": "unit-tests,mf-keys", "metadata_filter": json.dumps({"ключ": "значение"})},
+    ) as r2:
+        b2 = await r2.json()
+        assert r2.status == 200 and any(a["name"] == name for a in b2["assets"])
+
+
+@pytest.mark.asyncio
+async def test_meta_with_zero_and_boolean_lists(http, api_base, asset_factory, make_asset_bytes):
+    t = ["models", "checkpoints", "unit-tests", "mf-zero-bool"]
+    a0 = await asset_factory("mf_zero_count.safetensors", t, {"count": 0}, make_asset_bytes("z", 1025))
+    a1 = await asset_factory("mf_bool_list.safetensors", t, {"choices": [True, False]}, make_asset_bytes("b", 1026))
+
+    # count == 0 must match only a0
+    async with http.get(
+        api_base + "/api/assets",
+        params={"include_tags": "unit-tests,mf-zero-bool", "metadata_filter": json.dumps({"count": 0})},
+    ) as r1:
+        b1 = await r1.json()
+        assert r1.status == 200
+        names1 = [a["name"] for a in b1["assets"]]
+        assert a0["name"] in names1 and a1["name"] not in names1
+
+    # Any-of list of booleans: True matches second asset
+    async with http.get(
+        api_base + "/api/assets",
+        params={"include_tags": "unit-tests,mf-zero-bool", "metadata_filter": json.dumps({"choices": True})},
+    ) as r2:
+        b2 = await r2.json()
+        assert r2.status == 200 and any(a["name"] == a1["name"] for a in b2["assets"])
+
+
+@pytest.mark.asyncio
+async def test_meta_mixed_list_types_and_strictness(http, api_base, asset_factory, make_asset_bytes):
+    name = "mf_mixed_list.safetensors"
+    tags = ["models", "checkpoints", "unit-tests", "mf-mixed"]
+    meta = {"mix": ["1", 1, True, None]}
+    await asset_factory(name, tags, meta, make_asset_bytes(name, 1999))
+
+    # Should match because 1 is present
+    async with http.get(
+        api_base + "/api/assets",
+        params={"include_tags": "unit-tests,mf-mixed", "metadata_filter": json.dumps({"mix": [2, 1]})},
+    ) as r1:
+        b1 = await r1.json()
+        assert r1.status == 200 and any(a["name"] == name for a in b1["assets"])
+
+    # Should NOT match for False
+    async with http.get(
+        api_base + "/api/assets",
+        params={"include_tags": "unit-tests,mf-mixed", "metadata_filter": json.dumps({"mix": False})},
+    ) as r2:
+        b2 = await r2.json()
+        assert r2.status == 200 and not b2["assets"]
+
+
+@pytest.mark.asyncio
+async def test_meta_unknown_key_and_none_behavior_with_scope_tags(http, api_base, asset_factory, make_asset_bytes):
+    # Use a unique scope tag to avoid interference
+    t = ["models", "checkpoints", "unit-tests", "mf-unknown-scope"]
+    x = await asset_factory("mf_unknown_a.safetensors", t, {"k1": 1}, make_asset_bytes("ua"))
+    y = await asset_factory("mf_unknown_b.safetensors", t, {"k2": 2}, make_asset_bytes("ub"))
+
+    # Filtering by unknown key with None should return both (missing key OR null)
+    async with http.get(
+        api_base + "/api/assets",
+        params={"include_tags": "unit-tests,mf-unknown-scope", "metadata_filter": json.dumps({"unknown": None})},
+    ) as r1:
+        b1 = await r1.json()
+        assert r1.status == 200
+        names = {a["name"] for a in b1["assets"]}
+        assert x["name"] in names and y["name"] in names
+
+    # Filtering by unknown key with concrete value should return none
+    async with http.get(
+        api_base + "/api/assets",
+        params={"include_tags": "unit-tests,mf-unknown-scope", "metadata_filter": json.dumps({"unknown": "x"})},
+    ) as r2:
+        b2 = await r2.json()
+        assert r2.status == 200 and not b2["assets"]
+
+
+@pytest.mark.asyncio
+async def test_meta_with_tags_include_exclude_and_name_contains(http, api_base, asset_factory, make_asset_bytes):
+    # alpha matches epoch=1; beta has epoch=2
+    a = await asset_factory(
+        "mf_tag_alpha.safetensors",
+        ["models", "checkpoints", "unit-tests", "mf-tag", "alpha"],
+        {"epoch": 1},
+        make_asset_bytes("alpha"),
+    )
+    b = await asset_factory(
+        "mf_tag_beta.safetensors",
+        ["models", "checkpoints", "unit-tests", "mf-tag", "beta"],
+        {"epoch": 2},
+        make_asset_bytes("beta"),
+    )
+
+    params = {
+        "include_tags": "unit-tests,mf-tag,alpha",
+        "exclude_tags": "beta",
+        "name_contains": "mf_tag_",
+        "metadata_filter": json.dumps({"epoch": 1}),
+    }
+    async with http.get(api_base + "/api/assets", params=params) as r:
+        body = await r.json()
+        assert r.status == 200
+        names = [x["name"] for x in body["assets"]]
+        assert a["name"] in names
+        assert b["name"] not in names
+
+
+@pytest.mark.asyncio
+async def test_meta_sort_and_paging_under_filter(http, api_base, asset_factory, make_asset_bytes):
+    # Three assets in same scope with different sizes and a common filter key
+    t = ["models", "checkpoints", "unit-tests", "mf-sort"]
+    n1, n2, n3 = "mf_sort_1.safetensors", "mf_sort_2.safetensors", "mf_sort_3.safetensors"
+    await asset_factory(n1, t, {"group": "g"}, make_asset_bytes(n1, 1024))
+    await asset_factory(n2, t, {"group": "g"}, make_asset_bytes(n2, 2048))
+    await asset_factory(n3, t, {"group": "g"}, make_asset_bytes(n3, 3072))
+
+    # Sort by size ascending with paging
+    q = {"include_tags": "unit-tests,mf-sort", "metadata_filter": json.dumps({"group": "g"}), "sort": "size", "order": "asc", "limit": "2"}
+    async with http.get(api_base + "/api/assets", params=q) as r1:
+        b1 = await r1.json()
+        assert r1.status == 200
+        got1 = [a["name"] for a in b1["assets"]]
+        assert got1 == [n1, n2]
+        assert b1["has_more"] is True
+
+    q2 = {**q, "offset": "2"}
+    async with http.get(api_base + "/api/assets", params=q2) as r2:
+        b2 = await r2.json()
+        assert r2.status == 200
+        got2 = [a["name"] for a in b2["assets"]]
+        assert got2 == [n3]
+        assert b2["has_more"] is False