Registrar um assinante de newsletter do InstaWP para o Mailchimp

InstaWP permite que visitantes iniciem um site sandbox para testar um plugin, permitindo que se inscrevam na newsletter:

Iniciando um site de teste no InstaWP para testar o Gato GraphQL

Podemos capturar esses e-mails fornecendo um webhook ao InstaWP, na aba "Advanced Options" do template:

O webhook será uma persisted query com a query abaixo. Esta query captura o e-mail dos visitantes e inscreve esse e-mail em uma lista do Mailchimp.

query HasSubscribedToNewsletter {
  hasSubscriberOptIn: _httpRequestHasParam(name: "marketing_optin")
  subscriberOptIn: _httpRequestStringParam(name: "marketing_optin")
  isNotSubscriberOptInNAValue: _notEquals(value1: $__subscriberOptIn, value2: "NA")
  subscribedToNewsletter: _and(values: [$__hasSubscriberOptIn, $__isNotSubscriberOptInNAValue])
    @export(as: "subscribedToNewsletter")
}
 
query RegisterNewsletterSubscribeFromInstaWPToMailchimpList(
  # mailchimpDataCenterCode: Code for the data center of your account on Mailchimp (See: https://mailchimp.com/developer/marketing/docs/fundamentals/#api-structure)
  $mailchimpDataCenterCode: String!
  # Audience ID for the list on Mailchimp to which to subscribe the email
  $mailchimpAudienceID: String!
)
   @depends(on: "HasSubscribedToNewsletter")
   @include(if: $subscribedToNewsletter)
{
  subscriberEmail: _httpRequestStringParam(name: "email")
  
  mailchimpUsername: _env(name: "MAILCHIMP_API_CREDENTIALS_USERNAME")
    @remove
  mailchimpPassword: _env(name: "MAILCHIMP_API_CREDENTIALS_PASSWORD")
    @remove
  
  mailchimpAPIEndpoint: _sprintf(
    string: "https://%s.api.mailchimp.com/3.0/lists/%s/members",
    values: [$mailchimpDataCenterCode, $mailchimpAudienceID]
  )
  
  mailchimpListMembersJSONObject: _sendJSONObjectItemHTTPRequest(input: {
    url: $__mailchimpAPIEndpoint,
    method: POST,
    options: {
      auth: {
        username: $__mailchimpUsername,
        password: $__mailchimpPassword
      },
      json: {
        email_address: $__subscriberEmail,
        status: "subscribed"
      }
    }
  })
}

E definir em wp-config.php:

define( 'MAILCHIMP_API_CREDENTIALS_USERNAME', '{ username }' );
define( 'MAILCHIMP_API_CREDENTIALS_PASSWORD', '{ password }' );

Usando este webhook, ao criar um novo site de teste no InstaWP e o usuário se inscrever na newsletter, o e-mail do visitante é adicionado automaticamente à lista do Mailchimp: