> ## Documentation Index
> Fetch the complete documentation index at: https://developers.luccasoftware.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Respond to Activation

> How to respond to the challenge required for your webhook-endpoint activation.

Once your webhook-endpoint is declared in your Lucca account, our servers
will send a GET request to your endpoint with an `echo` string in query
parameters. You must respond with the challenge value in the response body.

<Note>Some domains are whitelisted and won't need to pass a confirmation challenge
(e.g. Zapier)</Note>

```http theme={null}
GET /your-webhook-endpoint HTTPS/2
?echo=iusiof24dsfxvcç834
Host: yourdomain.com

> Response
Content-Type: plain/text

iusiof24dsfxvcç834
```


## OpenAPI

````yaml webhook-client-api GET /{webhook-endpoint}
openapi: 3.1.0
info:
  title: webhook-client
  description: |-
    API reference for a webhook-client implementation, i.e. a endpoint
    that receives events from the Lucca API.
  version: '1.0'
  contact:
    name: API Support
    url: https://support.lucca.fr
    email: contact@luccasoftware.com
  license:
    name: Unlicensed
    url: https://www.luccasoftware.com
servers:
  - url: https://{domain}
    variables:
      domain:
        default: your-domain.com
security: []
tags:
  - name: Webhooks
    description: Webhooks.
paths:
  /{webhook-endpoint}:
    parameters:
      - in: path
        name: webhook-endpoint
        description: Name of the webhook-endpoint on your server.
        required: true
        schema:
          type: string
          maxLength: 500
    get:
      tags:
        - Webhooks
      summary: Respond to challenge
      description: Respond to the challenge in order to activate your webhook-endpoint.
      operationId: challenge-webhook-endpoint
      parameters:
        - name: echo
          description: The challenge value you must return
          in: query
          required: true
          schema:
            type: string
      responses:
        '200':
          description: OK
          content:
            text/plain:
              schema:
                type: string
                description: >-
                  When responding to the activation challenge workflow, return
                  the challenge value as a simple string. When receiving a
                  regular event, simply return an empty "200 OK". Refer to the
                  documentation for [all status codes and their
                  meaning](./spec-receive#response-status-codes).
      security: []

````