New users receive a bundle of free credits to try SMS.to from the web app (UI). These credits are intended for test messages to your own phone number so you can confirm delivery and see the flow. They are not a free, unlimited API allowance. To send via the API, you’ll need an active balance or plan after sign-up. If you’re evaluating the API, we’ll show you how to send a quick test to your number and what’s needed for production sending.