Webhooks are user-defined HTTP callbacks that are triggered by specific events. Whenever that trigger event occurs, the WhatsApp Business API client sees the event, collects the data, and immediately sends a notification (HTTP request) to the Webhook URL specified in the application settings updating the status of sent messages or indicating when you receive a message.
WhatsApp API Gateway supports webhooks. The webhook documentation is available here: https://developers.facebook.com/docs/whatsapp/api/webhooks/
To know more about WATI webhooks, please click here: https://docs.wati.io/webhooks/webhooks