One API, the same rules for every use case
Each guide above is a complete build: the endpoints involved, a working code sample, the compliance rules that apply to that kind of message, what it costs at the published rates, and the limits to plan around. They share a foundation.
The same primitives. Messages (POST /v1/messages), verification (POST /v1/verify and /v1/verify/check), batches for lists, webhooks for delivery status and replies, and scheduled sends. The API reference documents every endpoint.
The same price list. $0.009 per outbound message with carrier fees included, and $0.025 per successful verification. See pricing.
The same guardrails. Opt-out keywords are handled on every number, a suppression list gates every send, and a US local number can text the public only after its A2P 10DLC registration is approved. Marketing messages need the recipient's prior express written consent; transactional messages still need consent and a way to opt out. Opt-out and consent and compliance and registration explain what the platform enforces and what stays your responsibility.
The same sandbox. Every use case can be built and tested end to end with a free test key: simulated delivery, forced failures, signed webhooks and simulated replies. The free tier adds 100 live texts a month to numbers you have verified.
What SimpleSMS is not for
SimpleSMS sends SMS in the United States and Canada. It does not do voice calls, WhatsApp or outbound MMS, and it does not deliver to other countries. Messaging that the Messaging Policy prohibits is blocked whatever the use case.