Send a single message in one request. The body is a flat object — ideal for transactional, one-off messages. For high volume, use simple_send to batch up to 250 messages per call.

Extras. On WhatsApp, actions turns the message into reply buttons, a link button or a list. check_duplication_time_window skips the send when the same sender already messaged the recipient within that many hours (up to 72).

Set an internal_id to correlate the message with delivery webhooks; it defaults to the recipient phone number.

Response. HTTP 200 with a task_id and one entry per message. status is false when any message failed: failed entries come first and carry error (hex code) and details; accepted entries carry message_uuid (and conversation_uuid on two-way channels). Match entries by internal_id. Final delivery status is sent asynchronously to your configured webhook.

Whole-request errors. Invalid JSON field types return HTTP 200 with status: false, error_code 0x1 and no task_id. 402 (0x41) means the balance is depleted.

Authentication: stream token in the Authorization header (see Authentication in the API Overview).