langflow-ai/langflow · error · HTTPException

Flow {flow_id_str} not found

Error message

Flow {flow_id_str} not found

What it means

Error "Flow {flow_id_str} not found" thrown in langflow-ai/langflow.

Source

Thrown at src/backend/base/langflow/api/v1/endpoints.py:1194

    else:
        try:
            # Get the flow that matches the flow_id and belongs to the user
            # flow = session.query(Flow).filter(Flow.id == flow_id).filter(Flow.user_id == api_key_user.id).first()
            stmt = select(Flow).where(Flow.id == flow.id).where(Flow.user_id == api_key_user.id)
            flow = (await session.exec(stmt)).first()
        except sa.exc.StatementError as exc:
            # StatementError('(builtins.ValueError) badly formed hexadecimal UUID string')
            if "badly formed hexadecimal UUID string" in str(exc):
                await logger.aerror(f"Flow ID {flow_id_str} is not a valid UUID")
                # This means the Flow ID is not a valid UUID which means it can't find the flow
                raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail=str(exc)) from exc
            raise HTTPException(status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, detail=str(exc)) from exc
        except Exception as exc:
            raise HTTPException(status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, detail=str(exc)) from exc

        if flow is None:
            msg = f"Flow {flow_id_str} not found"
            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail=msg)

        if flow.data is None:
            msg = f"Flow {flow_id_str} has no data"
            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail=msg)
        try:
            graph_data = flow.data
            graph_data = process_tweaks(graph_data, tweaks or {})
            raise_if_hitl_unsupported(graph_data)
            graph = Graph.from_payload(graph_data, flow_id=flow_id_str)
        except CustomComponentValidationError as exc:
            raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail=str(exc)) from exc
        except HTTPException:
            raise
        except Exception as exc:
            raise HTTPException(status_code=status.HTTP_500_INTERNAL_SERVER_ERROR, detail=str(exc)) from exc

    try:
        task_result, session_id = await run_graph_internal(

View on GitHub (pinned to 976ec789d2)

Solutions

1. Verify the flow id is correct and the flow still exists.
2. Check that the authenticated user has access to the flow.

When it happens

Trigger: Occurs when the flow_id parsed from the request does not correspond to any flow row in the database.

Common situations: See trigger scenarios.

AI-assisted analysis of langflow-ai/langflow@976ec789d2 (2026-08-14). Data as JSON: /api/errors/850a22418e170da4. Report an issue: GitHub.