To use the Cloud API, businesses make calls to Meta’s Graph API to send messages and Webhooks to receive events, such as messages and status updates. The Graph API is a form of Remote Procedure Call expressed over HTTP, where operations and their parameters are expressed using a combination of URL parameters, headers, and request body.

A call to the Graph API from UNIX-based command lines looks like this:

curl -X POST \
https://graph.facebook.com/{{Version}}/{{Recipient-Phone-Number}}/messages \
  -H "Authorization: {{User-Access-Token}}" \
  -d '{
    "messaging_product": "whatsapp",
    "to": "1650XXXXXXX",
    "text": {"body" : "hi"}
 }'

Compared to the On-Premises implementation, a Graph API integration relies on a different authentication mechanism (see User Access Token), a different Webhook setup process (see Setup Webhooks), and has different latencies and error rates. For more information on how to use the Graph API, see the Graph API Developer Documentation.