langflow-ai/langflow · error · HTTPException

Flow not found

Error message

Flow not found

What it means

404 from the unauthenticated public-flow read endpoint (GET /api/v1/flows/public/{flow_id} or the read_public_flow handler): no Flow row with that id exists at all — this pre-check runs before the access_type check, so the id is simply unknown. Because the endpoint is anonymous, the 404 deliberately gives no ownership information.

Source

Thrown at src/backend/base/langflow/api/v1/flows.py:321

                    result[node.get("id")] = translated
    return result


@router.get("/public_flow/{flow_id}", response_model=FlowRead, status_code=200)
async def read_public_flow(
    *,
    session: DbSession,
    flow_id: UUID,
):
    """Read a public flow without requiring authorization (public means public).

    Because this endpoint is unauthenticated, secret field values (every template
    field marked ``password``) are stripped before returning so a PUBLIC flow does
    not leak the owner's stored API keys / credentials to anonymous callers.
    """
    flow = (await session.exec(select(Flow).where(Flow.id == flow_id))).first()
    if flow is None:
        raise HTTPException(status_code=404, detail="Flow not found")
    if flow.access_type is not AccessTypeEnum.PUBLIC:
        raise HTTPException(status_code=403, detail="Flow is not public")
    flow_read = FlowRead.model_validate(flow, from_attributes=True)
    flow_read.data = strip_secret_field_values(flow_read.data)
    return flow_read


@router.patch("/{flow_id}", response_model=FlowRead, status_code=200)
async def update_flow(
    *,
    session: DbSession,
    flow_id: UUID,
    db_flow: AuthorizedWriteFlow,
    flow: FlowUpdate,
    current_user: CurrentActiveUser,
    storage_service: Annotated[StorageService, Depends(get_storage_service)],
):
    """Update a flow."""

View on GitHub (pinned to 976ec789d2)

Solutions

  1. Confirm the flow still exists via an authenticated GET /api/v1/flows/{flow_id}
  2. If it exists but you get 403 instead, the flow is PRIVATE — the owner must flip access_type to PUBLIC
  3. Regenerate/re-share the public link from the live flow
Defensive patterns

Strategy: try-catch

Validate before calling

// If authenticated: cheap existence probe before sharing an anonymous link
const exists = await axios.get(`/api/v1/flows/${flowId}`).then(() => true, (e) => e.response?.status !== 404);

Try / catch

catch (e) {
  if (e.response?.status === 404) return showLinkExpired();
  if (e.response?.status === 403) return showNotPublic();
  throw e;
}

Prevention

When it happens

Trigger: Fetching a public flow URL with a deleted flow's id, a typo'd UUID, or an id from a different environment. Comes before the 403 'Flow is not public', so existence is the only thing that failed.

Common situations: Shared/public links outliving their flow (flow deleted or DB reset); published links pointing at a dev id while served by prod; UUID truncation when copy-pasting links.

Related errors

AI-assisted analysis of langflow-ai/langflow@976ec789d2 (2026-08-14). Data as JSON: /api/errors/222c928ffa1c3912. Report an issue: GitHub.