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Trigger flows with webhooks

You can use the Webhook component to start a flow run in response to an external event.

With the Webhook component, a flow can receive data directly from external sources. Then, the flow can parse the data and pass it to other components in the flow to initiate other actions, such as calling APIs, writing to databases, and chatting with LLMs.

The Webhook component provides a versatile entrypoint that can make your flows more event-driven and integrated with your entire stack of applications and services. For example:

  • Use an LLM to analyze the sentiment and content of customer feedback or survey responses.
  • Receive notifications from a monitoring system, and then trigger automated responses based on alert type and severity.
  • Integrate with e-commerce platforms to process orders and update inventory.

Configure the Webhook component​

To use the Webhook component in a flow, do the following:

  1. In Langflow, open the flow where you want to use the Webhook component.

  2. Add a Webhook component and a Parser component to your flow.

    The Parser component extracts relevant data from the raw payload received by the Webhook component.

  3. Connect the Webhook component's Data output to the Parser component's Data input.

  4. In the Parser component's Template field, enter a template to parse the raw payload into structured text.

    In the template, use variables for payload keys in the same way you would define variables in a Prompt component.

    For example, assume that you expect your Webhook component to receive the following JSON data:


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    {
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    "id": "",
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    "name": "",
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    "email": ""
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    }

    Then, you can use curly braces to reference the JSON keys anywhere in your parser template:


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    ID: {id} - Name: {name} - Email: {email}

  5. Connect the Parser component's Parsed Text output to the next logical component in your flow, such as a Chat Input component.

    If you want to test only the Webhook and Parser components, you can connect the Parsed Text output directly to a Chat Output component's Text input. Then, you can see the parsed data in the Playground after you run the flow.

  6. From the Webhook component's Endpoint field, copy the API endpoint that you will use to send data to the Webhook component and trigger the flow.

    Alternatively, to get a complete POST /v1/webhook/$FLOW_ID code snippet, open the flow's API access pane, and then click the Webhook cURL tab. You can also modify the default curl command in the Webhook component's cURL field. If this field isn't visible by default, click the Webhook component, and then click Controls in the component's header menu.

  7. Send a POST request with data to the flow's webhook endpoint to trigger the flow.

    The following example sends a payload containing id, name, and email strings:


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    curl -X POST "http://localhost:7860/api/v1/webhook/FLOW_ID" \
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    -H "Content-Type: application/json" \
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    -H "x-api-key: LANGFLOW_API_KEY" \
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    -d '{"id": "12345", "name": "alex", "email": "alex@email.com"}'

    A successful response indicates that Langflow started the flow:


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    {
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    "message": "Task started in the background",
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    "status": "in progress"
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    }

    The output for the entire flow isn't returned by the webhook endpoint.

  8. To view the flow's most recent parsed payload, click the Parser component, and then click Inspect output. For the preceding example, the parsed payload would be a string like ID: 12345 - Name: alex - Email: alex@email.com.

Troubleshoot Parser component build failure​

The Parser component can fail to build if it doesn't receive data from the Webhook component or if there is a problem with the incoming data.

If this occurs, try changing the Parser component's Mode to Stringify so that the component outputs the parsed payload as a single string.

Then, you can examine the string output and troubleshoot your parsing template, or work with the parsed data in string form.

Trigger flows with Composio webhooks​

Typically, you won't manually trigger the webhook component. To learn about triggering flows with payloads from external applications, see the video tutorial How to Use Webhooks in Langflow.

See also​

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