Send one or more SMS messages in a single request. Each message is queued and delivered independently, so a batch can partially succeed — always inspect every item in the response.

Sender modes — pick one:

• Batch: set one top-level sender for the whole request and omit sender on each message.

• Mixed: omit the top-level sender and set a sender on every message.

• Batch size: up to 250 messages per request.

• Correlation: set a unique internal_id per message; it is echoed back in the response and in delivery webhooks, and it keys any per-message error.

• Response: a batch task_id plus, per message, a message_uuid and conversation_uuid. Final delivery status is sent asynchronously to your configured webhook.

• Partial failures are reported inline on the offending message (error code + details).

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