How do I use additional custom fields in HTML templates for Opensend Postal?

In order to utilize additional custom fields in HTML templates, you will need to:

• Include additional custom fields (variables) in your HTML templates
  
• Add additional custom fields in your Postal configuration
  
  
  • If you use custom fields please add value for those custom fields to make sure test custom field values are generated properly in your postcard preview
    
    Note: If the preview of your postcard contains test values that you provided for custom fields, it means that your mapping is correct and you can proceed to the next step.
    
    
• Send Custom Fields to Opensend Postal Webhook
  

  {
  "integration_id": "Integration ID you copied from the dashboard",
  "email": "email address of the contact"
  "custom_fields": 
  { 
  "customfield1": "Value of custom field 1",
  "customfield2": "Value of custom field 2" 
  }
  }