Webhook
A webhook is a mechanism by which one system automatically notifies another of an event, sending an HTTP call to a predefined address the moment the event occurs. Unlike polling, where the software continuously queries the server, the information travels as push: in messaging, webhooks carry incoming messages, status updates and delivery confirmations in real time.
Technically, a webhook is a URL on your system that the external service calls with an HTTP request, usually a POST with a JSON body, when something happens: a message received, a delivery status changed, a payment completed. The receiver must respond quickly with a success code and process the content, because many providers retry the delivery on error and duplicates must be handled.
In WhatsApp marketing, webhooks are everywhere: Meta's API delivers inbound messages and status updates this way; messaging platforms expose webhooks towards your systems to notify new contacts or keywords; e-commerce sends webhooks on orders and carts to trigger messages. The essential practices: verify the signature of requests, respond immediately while moving the work to a queue, and handle idempotency on repeated events.
SendApp receives messages and statuses from WhatsApp, Telegram and Instagram via webhook, and exposes APIs and webhooks so you can connect your systems and automate sends when events occur.
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