Glossary

SMS glossary

Every entry opens with a one-sentence definition, then shows an example and points to the guide that covers the topic in depth.

Alphanumeric sender ID

An alphanumeric sender ID is text, such as a company name, that the recipient’s phone shows instead of the sender’s phone number. It has up to 11 characters: Latin letters, digits and spaces. A bulk SMS provider sets it, not a phone, and recipients usually cannot reply to it.

SMS API vs SMS gateway vs bulk SMS

An SMS API is the interface your code uses to send or receive a text message. An SMS gateway is the service or device that takes that request and hands the message to a mobile network. Bulk SMS means sending the same or similar text to many recipients at once, usually through a gateway with a sender ID.

SMS character limit

One SMS holds 160 characters when the text uses only the basic SMS alphabet (GSM-7), or 70 characters when it contains even one character outside it, such as an emoji or a Polish ł. Longer messages split into parts of 153 or 67 characters, and the recipient’s phone joins them back into one text.