diff --git a/surfsense_backend/app/notifications/api/transform.py b/surfsense_backend/app/notifications/api/transform.py
new file mode 100644
index 000000000..8970cb0b8
--- /dev/null
+++ b/surfsense_backend/app/notifications/api/transform.py
@@ -0,0 +1,62 @@
+"""Pure request/response helpers for the notifications API.
+
+No DB or framework objects, so these are unit-testable in isolation.
+"""
+
+from __future__ import annotations
+
+from datetime import datetime
+from typing import NamedTuple
+
+from app.notifications.api.schemas import NotificationResponse
+from app.notifications.persistence import Notification
+
+
+class SourceTypeFilter(NamedTuple):
+    """The notification types and JSONB facet a source-type filter selects."""
+
+    types: tuple[str, ...]
+    metadata_key: str
+    value: str
+
+
+def parse_source_type(source_type: str) -> SourceTypeFilter | None:
+    """Decode a `connector:<type>` / `doctype:<type>` filter, or None if unknown."""
+    if source_type.startswith("connector:"):
+        return SourceTypeFilter(
+            types=("connector_indexing", "connector_deletion"),
+            metadata_key="connector_type",
+            value=source_type[len("connector:") :],
+        )
+    if source_type.startswith("doctype:"):
+        return SourceTypeFilter(
+            types=("document_processing",),
+            metadata_key="document_type",
+            value=source_type[len("doctype:") :],
+        )
+    return None
+
+
+def parse_before_date(before_date: str) -> datetime:
+    """Parse an ISO date for pagination; raises ValueError if malformed."""
+    return datetime.fromisoformat(before_date.replace("Z", "+00:00"))
+
+
+def to_response(notification: Notification) -> NotificationResponse:
+    """Map a persisted notification to its API response shape."""
+    return NotificationResponse(
+        id=notification.id,
+        user_id=str(notification.user_id),
+        search_space_id=notification.search_space_id,
+        type=notification.type,
+        title=notification.title,
+        message=notification.message,
+        read=notification.read,
+        metadata=notification.notification_metadata or {},
+        created_at=notification.created_at.isoformat()
+        if notification.created_at
+        else "",
+        updated_at=notification.updated_at.isoformat()
+        if notification.updated_at
+        else None,
+    )