Developer API

Messaging infrastructure without the carrier complexity.

Send, track, and automate SMS through a clean REST API with sandbox testing and delivery webhooks.

Built for production

Separate send-only and read-only access for every integration.

Predictable limits and usage records per API key.

Receive status changes in your system as they happen.

POST

/v1/messages

Send to one number or a recipient list.

GET

/v1/balance

Read the account credit balance.

GET

/v1/messages/:id

Check campaign and delivery status.

Authorization: Bearer sts_live_••••••••
Content-Type: application/json

Sandbox mode is available before you use live credits.