Text messaging, or texting is the common term for the sending of "short" (160 characters or fewer) text messages from mobile phones using the Short Message Service (SMS). But if a text message that surpasses the 160 characters limit and goes on to another page, it could be referred as an epic text; after the style of lengthy poetry. It is available on most digital mobile phones and some personal digital assistants with on-board wireless telecommunications. The individual messages which are sent are called text messages, or in the more colloquial text speak texts.

SMS gateways exist to connect mobile SMS services with instant message (IM) services, the world wide web, desktop computers, and even landline telephones (through speech synthesis). Devices which can connect to mobile phones and PDAs through protocols such as Bluetooth can also sometimes use that link to send SMS messages over the wireless network. SMS arose as part of the widely deployed GSM protocol, but is now also available with non-GSM systems.

The most common application of the service is person-to-person messaging, but text messages are also often used to interact with automated systems, such as ordering products and services for mobile phones, or participating in contests. There are some services available on the Internet that allow users to send text messages free of direct charge to the sender, although users of all North American networks do not have to pay to receive any SMS text message.