Send an SMS message

POST /sms

Send a single SMS text message. Supports subscriber preference checks and scheduling.

TCPA compliance — actions required from you:

Configure the inbound webhook. Zyphr only processes STOP/opt-out replies if your SMS provider is pointed at our inbound endpoint. Until you do this, opt-outs never reach us and we will keep delivering. See Compliance Requirements.
Pass recipient_timezone (IANA, e.g. America/New_York) so quiet hours (8am-9pm recipient-local) can be enforced. Without it we send and record that quiet hours could not be evaluated. We deliberately do not infer a timezone from the area code — people keep numbers when they move.
Record consent for marketing sends. Marketing requires prior express written consent; express consent covers transactional only. With no record on file we deliver and flag it, which is a gap in your evidence, not permission.
Set classification. Unclassified messages are treated as marketing, the stricter reading.

Request

SMS message created