Monitor endpoints

import CodeSnippet from '@site/src/components/CodeSnippet'; import exampleApiMonitorGetVertexBuilds from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/get-vertex-builds.sh'; import resultApiMonitorResultGetVertexBuilds from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/result-get-vertex-builds.json'; import exampleApiMonitorDeleteVertexBuilds from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/delete-vertex-builds.sh'; import resultApiMonitorResultDeleteVertexBuilds from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/result-delete-vertex-builds.txt'; import exampleApiMonitorGetMessages from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/get-messages.sh'; import exampleApiMonitorGetMessages2 from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/get-messages-2.sh'; import resultApiMonitorResultGetMessages2 from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/result-get-messages-2.json'; import exampleApiMonitorDeleteMessages from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/delete-messages.sh'; import resultApiMonitorResultDeleteMessages from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/result-delete-messages.txt'; import exampleApiMonitorUpdateMessage from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/update-message.sh'; import resultApiMonitorResultUpdateMessage from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/result-update-message.json'; import exampleApiMonitorUpdateSessionId from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/update-session-id.sh'; import resultApiMonitorResultUpdateSessionId from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/result-update-session-id.json'; import exampleApiMonitorDeleteMessagesBySession from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/delete-messages-by-session.sh'; import resultApiMonitorResultDeleteMessagesBySession from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/result-delete-messages-by-session.txt'; import exampleApiMonitorExampleRequest from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/example-request.sh'; import exampleApiMonitorGetTransactions from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/get-transactions.sh'; import resultApiMonitorResultGetTransactions from '!!raw-loader!@site/docs/API-Reference/curl-examples/api-monitor/result-get-transactions.json'; import examplePythonApiMonitorExampleRequest from '!!raw-loader!@site/docs/API-Reference/python-examples/api-monitor/example-request.py'; import examplePythonApiMonitorGetVertexBuilds from '!!raw-loader!@site/docs/API-Reference/python-examples/api-monitor/get-vertex-builds.py'; import exampleJavascriptApiMonitorGetVertexBuilds from '!!raw-loader!@site/docs/API-Reference/javascript-examples/api-monitor/get-vertex-builds.js'; import examplePythonApiMonitorDeleteVertexBuilds from '!!raw-loader!@site/docs/API-Reference/python-examples/api-monitor/delete-vertex-builds.py'; import exampleJavascriptApiMonitorDeleteVertexBuilds from '!!raw-loader!@site/docs/API-Reference/javascript-examples/api-monitor/delete-vertex-builds.js'; import examplePythonApiMonitorGetMessages from '!!raw-loader!@site/docs/API-Reference/python-examples/api-monitor/get-messages.py'; import exampleJavascriptApiMonitorGetMessages from '!!raw-loader!@site/docs/API-Reference/javascript-examples/api-monitor/get-messages.js'; import examplePythonApiMonitorGetMessages2 from '!!raw-loader!@site/docs/API-Reference/python-examples/api-monitor/get-messages-2.py'; import exampleJavascriptApiMonitorGetMessages2 from '!!raw-loader!@site/docs/API-Reference/javascript-examples/api-monitor/get-messages-2.js'; import examplePythonApiMonitorDeleteMessages from '!!raw-loader!@site/docs/API-Reference/python-examples/api-monitor/delete-messages.py'; import exampleJavascriptApiMonitorDeleteMessages from '!!raw-loader!@site/docs/API-Reference/javascript-examples/api-monitor/delete-messages.js'; import examplePythonApiMonitorUpdateMessage from '!!raw-loader!@site/docs/API-Reference/python-examples/api-monitor/update-message.py'; import exampleJavascriptApiMonitorUpdateMessage from '!!raw-loader!@site/docs/API-Reference/javascript-examples/api-monitor/update-message.js'; import examplePythonApiMonitorUpdateSessionId from '!!raw-loader!@site/docs/API-Reference/python-examples/api-monitor/update-session-id.py'; import exampleJavascriptApiMonitorUpdateSessionId from '!!raw-loader!@site/docs/API-Reference/javascript-examples/api-monitor/update-session-id.js'; import examplePythonApiMonitorDeleteMessagesBySession from '!!raw-loader!@site/docs/API-Reference/python-examples/api-monitor/delete-messages-by-session.py'; import exampleJavascriptApiMonitorDeleteMessagesBySession from '!!raw-loader!@site/docs/API-Reference/javascript-examples/api-monitor/delete-messages-by-session.js'; import examplePythonApiMonitorGetTransactions from '!!raw-loader!@site/docs/API-Reference/python-examples/api-monitor/get-transactions.py'; import exampleJavascriptApiMonitorGetTransactions from '!!raw-loader!@site/docs/API-Reference/javascript-examples/api-monitor/get-transactions.js';

import Tabs from '@theme/Tabs'; import TabItem from '@theme/TabItem';

The /monitor endpoints are for internal Langflow functionality, primarily related to running flows in the Playground, storing chat history, and generating flow logs.

This information is primarily for those who are building custom components or contributing to the Langflow codebase in a way that requires calling or understanding these endpoints.

For typical application development with Langflow, there are more appropriate options for monitoring, debugging, and memory management. For more information, see the following:

Logs: Langflow log storage locations, customization options, and where to view logs in the visual editor
Test flows in the Playground: Run flows and inspect message history
Memory management options: Langflow storage locations and options, including the database, cache, and chat history

Vertex builds

The Vertex build endpoints (/monitor/builds) are exclusively for Playground functionality.

When you run a flow in the Playground, Langflow calls the /build/$FLOW_ID/flow endpoint in chat.py. This call retrieves the flow data, builds a graph, and executes the graph. As each component (or node) is executed, the build_vertex function calls build_and_run, which may call the individual components' def_build method, if it exists. If a component doesn't have a def_build function, the build still returns a component.

The build function allows components to execute logic at runtime. For example, the Recursive Character Text Splitter component is a child of the LCTextSplitterComponent class. When text needs to be processed, the parent class's build method is called, which creates a RecursiveCharacterTextSplitter object and uses it to split the text according to the defined parameters. The split text is then passed on to the next component. This all occurs when the component is built.

Get Vertex builds

Retrieve Vertex builds for a specific flow.

<Tabs> <TabItem value="Python" label="Python" default> <CodeSnippet source={examplePythonApiMonitorGetVertexBuilds} language="python" /> </TabItem> <TabItem value="JavaScript" label="JavaScript"> <CodeSnippet source={exampleJavascriptApiMonitorGetVertexBuilds} language="javascript" /> </TabItem> <TabItem value="curl" label="curl"> <CodeSnippet source={exampleApiMonitorGetVertexBuilds} language="bash" /> </TabItem> </Tabs> <details> <summary>Result</summary> <CodeSnippet source={resultApiMonitorResultGetVertexBuilds} language="json" /> </details>

Delete Vertex builds

Delete Vertex builds for a specific flow.

<Tabs> <TabItem value="Python" label="Python" default> <CodeSnippet source={examplePythonApiMonitorDeleteVertexBuilds} language="python" /> </TabItem> <TabItem value="JavaScript" label="JavaScript"> <CodeSnippet source={exampleJavascriptApiMonitorDeleteVertexBuilds} language="javascript" /> </TabItem> <TabItem value="curl" label="curl"> <CodeSnippet source={exampleApiMonitorDeleteVertexBuilds} language="bash" /> </TabItem> </Tabs> <details> <summary>Result</summary> <CodeSnippet source={resultApiMonitorResultDeleteVertexBuilds} language="text" /> </details>

Messages endpoints

The /monitor/messages endpoints store, retrieve, edit, and delete records in the message table in langflow.db Typically, these are called implicitly when running flows that produce message history, or when inspecting and modifying Playground memories.

Get messages

Retrieve a list of all messages:

To filter messages, use the flow_id, session_id, sender, and sender_name query parameters.

To sort the results, use the order_by query parameter.

This example retrieves messages sent by Machine and AI in a given chat session (session_id) and orders the messages by timestamp.

<Tabs> <TabItem value="Python" label="Python" default> <CodeSnippet source={examplePythonApiMonitorGetMessages2} language="python" /> </TabItem> <TabItem value="JavaScript" label="JavaScript"> <CodeSnippet source={exampleJavascriptApiMonitorGetMessages2} language="javascript" /> </TabItem> <TabItem value="curl" label="curl"> <CodeSnippet source={exampleApiMonitorGetMessages2} language="bash" /> </TabItem> </Tabs> <details> <summary>Result</summary> <CodeSnippet source={resultApiMonitorResultGetMessages2} language="json" /> </details>

Delete messages

Delete specific messages by their IDs.

This example deletes the message retrieved in the previous GET /messages example.

<Tabs> <TabItem value="Python" label="Python" default> <CodeSnippet source={examplePythonApiMonitorDeleteMessages} language="python" /> </TabItem> <TabItem value="JavaScript" label="JavaScript"> <CodeSnippet source={exampleJavascriptApiMonitorDeleteMessages} language="javascript" /> </TabItem> <TabItem value="curl" label="curl"> <CodeSnippet source={exampleApiMonitorDeleteMessages} language="bash" /> </TabItem> </Tabs> <details> <summary>Result</summary> <CodeSnippet source={resultApiMonitorResultDeleteMessages} language="text" /> </details>

Update message

Update a specific message by its ID.

This example updates the text value of message 3ab66cc6-c048-48f8-ab07-570f5af7b160.

<Tabs> <TabItem value="Python" label="Python" default> <CodeSnippet source={examplePythonApiMonitorUpdateMessage} language="python" /> </TabItem> <TabItem value="JavaScript" label="JavaScript"> <CodeSnippet source={exampleJavascriptApiMonitorUpdateMessage} language="javascript" /> </TabItem> <TabItem value="curl" label="curl"> <CodeSnippet source={exampleApiMonitorUpdateMessage} language="bash" /> </TabItem> </Tabs> <details> <summary>Result</summary> <CodeSnippet source={resultApiMonitorResultUpdateMessage} language="json" /> </details>

Update session ID

Update the session ID for messages.

This example updates the session_ID value 01ce083d-748b-4b8d-97b6-33adbb6a528a to different_session_id.

<Tabs> <TabItem value="Python" label="Python" default> <CodeSnippet source={examplePythonApiMonitorUpdateSessionId} language="python" /> </TabItem> <TabItem value="JavaScript" label="JavaScript"> <CodeSnippet source={exampleJavascriptApiMonitorUpdateSessionId} language="javascript" /> </TabItem> <TabItem value="curl" label="curl"> <CodeSnippet source={exampleApiMonitorUpdateSessionId} language="bash" /> </TabItem> </Tabs> <details> <summary>Result</summary> <CodeSnippet source={resultApiMonitorResultUpdateSessionId} language="json" /> </details>

Delete messages by session

Delete all messages for a specific session.

<Tabs> <TabItem value="Python" label="Python" default> <CodeSnippet source={examplePythonApiMonitorDeleteMessagesBySession} language="python" /> </TabItem> <TabItem value="JavaScript" label="JavaScript"> <CodeSnippet source={exampleJavascriptApiMonitorDeleteMessagesBySession} language="javascript" /> </TabItem> <TabItem value="curl" label="curl"> <CodeSnippet source={exampleApiMonitorDeleteMessagesBySession} language="bash" /> </TabItem> </Tabs> <details> <summary>Result</summary> <CodeSnippet source={resultApiMonitorResultDeleteMessagesBySession} language="text" /> </details>

Get traces

Retrieve trace metadata and span trees for a specific flow.

Example request

Use GET /monitor/traces and filter by flow_id:

const baseUrl = process.env.LANGFLOW_SERVER_URL ?? "http://localhost:7860";
const apiKey = process.env.LANGFLOW_API_KEY!;
const flowId = "YOUR_FLOW_ID";

async function listTraces() {
  const url = new URL("/api/v1/monitor/traces", baseUrl);
  url.searchParams.set("flow_id", flowId);
  url.searchParams.set("page", "1");
  url.searchParams.set("size", "50");

  const res = await fetch(url.toString(), {
    headers: {
      accept: "application/json",
      "x-api-key": apiKey,
    },
  });

  if (!res.ok) {
    throw new Error(`Request failed with status ${res.status}`);
  }

  const data = await res.json();
  console.log(data);
}

listTraces().catch(console.error);

</TabItem> <TabItem value="curl" label="curl"> <CodeSnippet source={exampleApiMonitorExampleRequest} language="bash" /> </TabItem> </Tabs>

Example response

json

{
  "traces": [
    {
      "id": "426656db-fc3c-4a3a-acf8-c60acf099543",
      "name": "Simple Agent - 9e774f60-857b-44b4-bbcd-87bd23848ee8",
      "status": "ok",
      "startTime": "2026-03-03T19:13:30.692628Z",
      "totalLatencyMs": 18693,
      "totalTokens": 2050,
      "flowId": "9e774f60-857b-44b4-bbcd-87bd23848ee8",
      "sessionId": "9e774f60-857b-44b4-bbcd-87bd23848ee8",
      "input": {
        "input_value": "Use tools to teach me about vertex graphs"
      },
      "output": {
        "message": {
          "text_key": "text",
          "data": {
            "timestamp": "2026-03-03 19:13:30 UTC",
            "sender": "Machine",
            "sender_name": "AI",
            "session_id": "9e774f60-857b-44b4-bbcd-87bd23848ee8",
            "text": "I can teach you the concept, but I couldn’t pull the Wikipedia pages with the tool ... (truncated)"
          }
        }
      }
    }
  ],
  "total": 1,
  "pages": 1
}

Get transactions

Retrieve all transactions, which are interactions between components, for a specific flow. This information is also available in flow logs.

<Tabs> <TabItem value="Python" label="Python" default> <CodeSnippet source={examplePythonApiMonitorGetTransactions} language="python" /> </TabItem> <TabItem value="JavaScript" label="JavaScript"> <CodeSnippet source={exampleJavascriptApiMonitorGetTransactions} language="javascript" /> </TabItem> <TabItem value="curl" label="curl"> <CodeSnippet source={exampleApiMonitorGetTransactions} language="bash" /> </TabItem> </Tabs> <details> <summary>Result</summary> <CodeSnippet source={resultApiMonitorResultGetTransactions} language="json" /> </details>