Product
SMS API
Send a single message with POST /v1/messages. Include an Idempotency-Key. Authenticate with a Bearer API key. The dashboard composer uses the same send pipeline.
Idempotent send
Replay the same key and body; a different body with the same key is a conflict.
Inspect later
GET /v1/messages/:id returns status, segments, and failure reason — not a fake delivered flag.
TEST vs LIVE
sms_test_ keys cannot send LIVE traffic. Sandbox sender TAYSEND is for TEST.
Encoding
GSM-7 vs UCS-2 is computed from the body. Unicode characters increase segments.