Webhooks enable event-driven communication from your LangGraph Platform application to external services. For example, you may want to issue an update to a separate service once an API call to LangGraph Platform has finished running. Many LangGraph Platform endpoints accept a webhook parameter. If this parameter is specified by an endpoint that can accept POST requests, LangGraph Platform will send a request at the completion of a run. When working with LangGraph Platform, you may want to use webhooks to receive updates after an API call completes. Webhooks are useful for triggering actions in your service once a run has finished processing. To implement this, you need to expose an endpoint that can accept POST requests and pass this endpoint as a webhook parameter in your API request. Currently, the SDK does not provide built-in support for defining webhook endpoints, but you can specify them manually using API requests.

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Supported endpoints

The following API endpoints accept a webhook parameter:
OperationHTTP MethodEndpoint
Create RunPOST/thread/{thread_id}/runs
Create Thread CronPOST/thread/{thread_id}/runs/crons
Stream RunPOST/thread/{thread_id}/runs/stream
Wait RunPOST/thread/{thread_id}/runs/wait
Create CronPOST/runs/crons
Stream Run StatelessPOST/runs/stream
Wait Run StatelessPOST/runs/wait
In this guide, we’ll show how to trigger a webhook after streaming a run.

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Set up your assistant and thread

Before making API calls, set up your assistant and thread. 
from langgraph_sdk import get_client

client = get_client(url=<DEPLOYMENT_URL>)
assistant_id = "agent"
thread = await client.threads.create()
print(thread)
Example response: 
{
    "thread_id": "9dde5490-2b67-47c8-aa14-4bfec88af217",
    "created_at": "2024-08-30T23:07:38.242730+00:00",
    "updated_at": "2024-08-30T23:07:38.242730+00:00",
    "metadata": {},
    "status": "idle",
    "config": {},
    "values": null
}

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Use a webhook with a graph run

To use a webhook, specify the webhook parameter in your API request. When the run completes, LangGraph Platform sends a POST request to the specified webhook URL. For example, if your server listens for webhook events at https://my-server.app/my-webhook-endpoint, include this in your request: 
input = { "messages": [{ "role": "user", "content": "Hello!" }] }

async for chunk in client.runs.stream(
    thread_id=thread["thread_id"],
    assistant_id=assistant_id,
    input=input,
    stream_mode="events",
    webhook="https://my-server.app/my-webhook-endpoint"
):
    pass

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Webhook payload

LangGraph Platform sends webhook notifications in the format of a Run. See the API Reference for details. The request payload includes run input, configuration, and other metadata in the kwargs field.

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Secure webhooks

To ensure only authorized requests hit your webhook endpoint, consider adding a security token as a query parameter: 
https://my-server.app/my-webhook-endpoint?token=YOUR_SECRET_TOKEN
Your server should extract and validate this token before processing requests.

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Disable webhooks

As of langgraph-api>=0.2.78, developers can disable webhooks in the langgraph.json file: 
{
  "http": {
    "disable_webhooks": true
  }
}
This feature is primarily intended for self-hosted deployments, where platform administrators or developers may prefer to disable webhooks to simplify their security posture—especially if they are not configuring firewall rules or other network controls. Disabling webhooks helps prevent untrusted payloads from being sent to internal endpoints. For full configuration details, refer to the configuration file reference.

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Test webhooks

You can test your webhook using online services like:
  • Beeceptor – Quickly create a test endpoint and inspect incoming webhook payloads.
  • Webhook.site – View, debug, and log incoming webhook requests in real time.
These tools help you verify that LangGraph Platform is correctly triggering and sending webhooks to your service.