langflow-ai · TahirMurtaza · Jun 9, 2026 · Jun 9, 2026 · Jun 10, 2026
diff --git a/docs/docs/Develop/environment-variables.mdx b/docs/docs/Develop/environment-variables.mdx
@@ -457,6 +457,7 @@ See [Telemetry](/contributing-telemetry).
 | `LANGFLOW_MAX_TRANSACTIONS_TO_KEEP` | Integer | `3000` | Maximum number of flow transaction events to keep in the database. |
 | `LANGFLOW_MAX_VERTEX_BUILDS_TO_KEEP` | Integer | `3000` | Maximum number of vertex builds to keep in the database. Relates to [Playground](/concepts-playground) functionality. |
 | `LANGFLOW_MAX_VERTEX_BUILDS_PER_VERTEX` | Integer | `2` | Maximum number of builds to keep per vertex. Older builds are deleted. Relates to [Playground](/concepts-playground) functionality. |
+| `LANGFLOW_TRACES_DB_TIMEOUT` | Float | `5.0` | Timeout in seconds for trace list and detail database queries in the monitor API. Increase this value if paginated trace queries time out on large flows. |
 | `LANGFLOW_PUBLIC_FLOW_CLEANUP_INTERVAL` | Integer | `3600` | The interval in seconds at which data for [shared Playground](/concepts-playground#share-a-flows-playground) flows are cleaned up. Default: 3600 seconds (1 hour). Minimum: 600 seconds (10 minutes). |
 | `LANGFLOW_PUBLIC_FLOW_EXPIRATION` | Integer | `86400` | The time in seconds after which a [shared Playground](/concepts-playground#share-a-flows-playground) flow is considered expired and eligible for cleanup. Default: 86400 seconds (24 hours). Minimum: 600 seconds (10 minutes). |
 

diff --git a/docs/docs/Develop/traces.mdx b/docs/docs/Develop/traces.mdx
@@ -49,6 +49,8 @@ To view traces in the Langflow UI, do the following:
 To programmatically query traces, use the `/monitor/traces` endpoints.
 For full parameter details and code examples in Python, TypeScript, and curl, see [Monitor endpoints: Get traces](/api-monitor#get-traces).
 
+If paginated trace queries time out on large flows, increase `LANGFLOW_TRACES_DB_TIMEOUT` (default: `5.0` seconds). See [Environment variables](/environment-variables).
+
 ## See also
 
 - [Logs](/logging)

diff --git a/src/backend/base/langflow/api/v1/traces.py b/src/backend/base/langflow/api/v1/traces.py
@@ -30,18 +30,20 @@
     TraceTable,
 )
 from langflow.services.database.models.user.model import User
-from langflow.services.deps import session_scope
+from langflow.services.deps import get_settings_service, session_scope
 from langflow.services.tracing.repository import fetch_single_trace, fetch_traces
 from langflow.services.tracing.validation import sanitize_query_string
 
 logger = logging.getLogger(__name__)
 
-# Keeps the API responsive when the trace table doesn't exist yet or the DB is slow at startup.
-DB_TIMEOUT = 5.0
-
 router = APIRouter(prefix="/monitor/traces", tags=["Traces"])
 
 
+def _get_traces_db_timeout() -> float:
+    """Keeps the API responsive when the trace table doesn't exist yet or the DB is slow."""
+    return get_settings_service().settings.traces_db_timeout
+
+
 @router.get("", response_model_by_alias=True)
 async def get_traces(
     current_user: Annotated[User, Depends(get_current_active_user)],
@@ -70,6 +72,7 @@ async def get_traces(
     Returns:
         List of traces
     """
+    db_timeout = _get_traces_db_timeout()
     try:
         sanitized_query = sanitize_query_string(query)
         # Frontend uses 0-based pages; repository expects 1-based.
@@ -86,10 +89,10 @@ async def get_traces(
                 effective_page,
                 size,
             ),
-            timeout=DB_TIMEOUT,
+            timeout=db_timeout,
         )
     except asyncio.TimeoutError:
-        logger.warning("Traces query timed out after %ss (table may not exist or DB is slow)", DB_TIMEOUT)
+        logger.warning("Traces query timed out after %ss (table may not exist or DB is slow)", db_timeout)
         return TraceListResponse(traces=[], total=0, pages=0)
     except (OperationalError, ProgrammingError) as e:
         logger.debug("Database error getting traces (table may not exist): %s", e)
@@ -113,17 +116,18 @@ async def get_trace(
     Returns:
         TraceRead containing the trace and its hierarchical span tree.
     """
+    db_timeout = _get_traces_db_timeout()
     try:
         result = await asyncio.wait_for(
             fetch_single_trace(current_user.id, trace_id),
-            timeout=DB_TIMEOUT,
+            timeout=db_timeout,
         )
         if result is None:
             raise HTTPException(status_code=404, detail="Trace not found")
     except HTTPException:
         raise
     except asyncio.TimeoutError:
-        logger.warning("Single trace query timed out after %ss", DB_TIMEOUT)
+        logger.warning("Single trace query timed out after %ss", db_timeout)
         raise HTTPException(status_code=504, detail="Database query timed out") from None
     except (OperationalError, ProgrammingError) as e:
         logger.debug("Database error getting trace: %s", e)

diff --git a/src/backend/tests/unit/api/v1/test_traces_api.py b/src/backend/tests/unit/api/v1/test_traces_api.py
@@ -224,6 +224,31 @@ async def _fetch(*_args, **_kwargs):
 
         assert resp.status_code == 422
 
+    def test_should_use_configured_db_timeout(self, client: TestClient):
+        captured_timeouts: list[float] = []
+
+        async def _fetch(*_args, **_kwargs):
+            return _empty_list_response()
+
+        async def _wait_for(coro, *, timeout):
+            captured_timeouts.append(timeout)
+            return await coro
+
+        settings = MagicMock()
+        settings.traces_db_timeout = 30.0
+        settings_service = MagicMock()
+        settings_service.settings = settings
+
+        with (
+            patch("langflow.api.v1.traces.get_settings_service", return_value=settings_service),
+            patch("langflow.api.v1.traces.asyncio.wait_for", side_effect=_wait_for),
+            patch("langflow.api.v1.traces.fetch_traces", side_effect=_fetch),
+        ):
+            resp = client.get(self._PATH)
+
+        assert resp.status_code == 200
+        assert captured_timeouts == [30.0]
+
 
 class TestGetTrace:
     def _path(self, trace_id: UUID | None = None) -> str:

diff --git a/src/lfx/src/lfx/services/settings/groups/observability.py b/src/lfx/src/lfx/services/settings/groups/observability.py
@@ -1,4 +1,4 @@
-from pydantic import BaseModel
+from pydantic import BaseModel, Field
 
 
 class ObservabilitySettings(BaseModel):
@@ -21,3 +21,5 @@ class ObservabilitySettings(BaseModel):
     If retroactively lowered below the current count for a flow,
     the oldest entries are deleted only when the next entry is created.
     """
+    traces_db_timeout: float = Field(default=5.0, gt=0)
+    """Timeout in seconds for trace list and detail database queries in the monitor API."""
diff --git a/src/lfx/tests/unit/services/settings/test_settings_composition.py b/src/lfx/tests/unit/services/settings/test_settings_composition.py
@@ -101,6 +101,7 @@
     "max_vertex_builds_to_keep",
     "max_vertex_builds_per_vertex",
     "max_flow_version_entries_per_flow",
+    "traces_db_timeout",
     # SecuritySettings
     "cors_origins",
     "cors_allow_credentials",