Definition
An SMS API is a web interface, usually REST over HTTPS with JSON, that lets software send SMS, receive replies and get delivery statuses programmatically, without managing telecom connections directly.
A typical call posts the recipient in E.164 format, the sender ID and the text to an endpoint with an API token, and gets back a message ID. Delivery statuses and inbound replies arrive later via webhooks.
Compared with SMPP, an HTTP API is easier to integrate, works through standard firewalls and fits serverless and web applications. SMPP is more efficient for very high sustained volume.
Good practice: keep tokens server-side, make sends idempotent so retries do not double-send, handle 429 rate-limit responses, and verify webhook requests.
The OmniChannels.ai REST API at api.broadnet.me uses Bearer-token authentication and covers SMS alongside WhatsApp, RCS and other channels.
Example
POST /sms {"to":"+971501234567","from":"AcmeBank","text":"Your code is 482913"}