Definition
A REST API is a web interface that exposes resources, such as messages, contacts or templates, at URLs and lets programs create, read, update and delete them with standard HTTP methods (POST, GET, PATCH, DELETE), usually exchanging JSON.
REST (representational state transfer) is an architectural style described by Roy Fielding in 2000. In practice, a messaging REST API means sending an authenticated HTTPS request, for example POST /messages with a JSON body, and receiving a JSON response with an ID and status. HTTP status codes signal the outcome: 2xx success, 4xx client errors such as invalid numbers or missing authorisation, 5xx server errors.
Typical patterns: bearer-token authentication in the Authorization header, idempotency keys so retries do not send duplicates, pagination for lists, rate limits with retry-after headers, and webhooks for asynchronous results such as delivery reports.
REST suits most integrations: CRMs, e-commerce platforms and back-office systems. For very high-volume SMS, carriers and aggregators often use SMPP instead, which keeps a persistent connection open.
An OpenAPI specification describes the endpoints in a machine-readable way, so client SDKs, documentation and tests can be generated from it.
OmniChannels.ai provides a REST/JSON API at https://api.broadnet.me with bearer-token authentication, an OpenAPI 3.1 specification and a TypeScript SDK.
Example
POST https://api.broadnet.me/… with header "Authorization: Bearer <token>" and a JSON body; the response returns a message ID.