Send message
Sends a WhatsApp message to a recipient. The type field determines the structure of the body and which additional object must be included (for example, text, image, template).
Authentication
Request
Recipient. Two alternative formats: a number in E.164 format (^\+[1-9]\d{1,14}\$, e.g. +5215512345678) or a BSUID (^[A-Z]{2}\.[A-Za-z0-9]{1,128}\$, e.g. MX.1264908862298277) — the anonymous contact id Meta assigns on “Click to WhatsApp” flows, carried by inbound webhooks in message.from_user_id. If neither format matches, the API rejects with 400. Note: a BSUID has no real phone number behind it, so if the send fails and an SMS fallback was requested, the chain is marked exhausted directly without attempting the SMS.
Optional. message_id (wamid) of a previous message this one replies to; the recipient sees it quoted.
Provide link or id, but not both.
Provide link or id, but not both.
Provide link or id, but not both.
Provide link or id, but not both.
Provide link or id, but not both.
Dynamic values for sending a template. carousel and buttons cannot coexist at the root.
Optional SMS fallback for this send: if the WhatsApp message fails definitively (synchronously or through a status webhook), the API automatically retries the same recipient over SMS with this content. It fires only once per message (atomic lock: if the synchronous failure and a late webhook arrive almost simultaneously, only the first one triggers it) and it is a single hop — no further cascade. Requires the multichannel fallback to be enabled for the account (errorCode 380/381 otherwise). If fallback is not sent, behavior is exactly the current one.
Response
Message identifier in Meta (wamid.xxx). Comes empty ("") when the send failed synchronously and the SMS fallback was activated.
Indicates that Meta accepted the send request (accepted), or queued when the send failed synchronously and the request included fallback.sms (the backup SMS was queued).
Only present when the send failed synchronously and the request included fallback.sms: identifier to correlate the backup SMS in the webhooks (its status events arrive as SMS webhooks carrying this id as message_id, plus origin_identifier pointing back to the WhatsApp send). When the fallback fires later through a status webhook instead, correlate through origin_identifier.