2.1. The following are the definition of terms and abbreviations that are used all throughout this document:
| Term | Description |
| API | API Application Programming Interface. |
| API Client | It refers to the User’s API client program; more specifically, the HTTP user-agent meant to use the API. Every API Client is provisioned and provided with a unique id for authentication / authorization. |
| Endpoint | An HTTP URL to which a user-agent will invoke one using one of the many HTTP methods; |
| HTTP | Hypertext Transfer Protocol
See http://www.ietf.org/rfc/rfc2616.txt |
| HTTPS | Hypertext Transfer Protocol Secure |
| Messaging Gateway (MGW) | The system responsible for sending and receiving messages (SMS).
This system enables Users, using an API Client, to be able to send (MT) documents and/or receive (MO) documents via the assigned VirtualShortcode. |
| MO Document | It refers to messages sent from the Subscriber’s mobile phone. |
| MT Document | It refers to messages sent to the Subscriber’s mobile phone. |
| REST | Representational State Transfer, an architectural style. |
| Subscriber | It refers to a unique mobile subscriber identified by an MSISDN. |
| Telco | It refers to the mobile carrier / operator. |
| User | The person / organization / entity intending to use the Messaging Gateway. |
| VirtualShortCode | A unique, Telco-agnostic shortcode resource provisioned in the Messaging Gateway;
This is provisioned and provided per User basis |
