Connect a WhatsApp Business number through the Meta Cloud API.
Relay receives WhatsApp messages through Meta's Cloud API webhook and replies on the same thread, so a customer messages the number they already have saved.
What you need from Meta
| Value | Where it comes from |
|---|---|
| Verify token | You choose it; Meta echoes it back during webhook setup |
| App secret | Your Meta app's settings, used to verify signatures |
| Phone number ID | The WhatsApp Business number you are connecting |
| Access token | Grants Relay permission to send on that number |
Set up the webhook
Point Meta at Relay
In your Meta app's WhatsApp configuration, set the callback URL to Relay's WhatsApp webhook endpoint and supply your verify token.
Complete verification
Meta issues a GET with a challenge. Relay answers it if the verify token matches, and the subscription goes live.
Subscribe to messages
Subscribe the app to the message webhook field so inbound messages are delivered.
Signature verification
Every inbound payload is checked against the app secret before it is processed. A request with a missing or wrong signature is rejected, which is why the app secret must be configured, not left blank in development and forgotten.
In the inbox
WhatsApp conversations land in the same inbox as widget conversations, and a human reply routes back out over WhatsApp automatically.