A to Z Glossary

The table below details specific terminology and slang commonly used in the telecom industry. You may well come across them now and again so we’d like to help you get to grips with what they actually mean!

Term  Description

Application Programming Interface. MessageBird has different APIs to suit your needs! Use our APIs to connect your application to us and send SMS and Voice messages automatically.

ASP An Application Service Provider typically builds the system (the 'application') that enables brands to communicate with their customers via SMS, or another mobile channel.
Batch import See “Bulk SMS”.
Bulk SMS

A term used to describe the mass submission of SMS messages, at the same time. Also known as a "Batch Import".


The number of letters, numbers, spaces and symbols in an SMS message.

Concatenated SMS

Overcomes the limitations imposed by the maximum number of characters that can be sent in a single SMS message, which is usually 160. A message longer than 160 characters is split into a number of smaller messages, sent and then received as one long message by your recipient.

Dedicated Short Code

Also known as “Unique” – this code is owned solely by you and all traffic received by the code is directed to your application.


Delivery Receipts: confirmation of successful or failed message delivery to an end user handset.

HLR Lookup

Provides information from the Home Location Register database, which holds vital information, including addresses, a list of active mobile numbers and whether or not the subscriber or device is roaming.

Keyword A short word that a user places at the beginning of an SMS message when responding to a Short Code. The keyword will trigger a particular response from the application that receives the response.

MNP (Mobile Number Portability)

Mobile Number Portability: users can retain their mobile number when switching between one mobile operator and another. In the countries where MNP is supported, MessageBird is able to determine and route the message through to the appropriate operator.


Mobile Subscriber Integrated Services Digital Number: the telephone number associated with the SIM card in a mobile phone.

One-way messaging

Messages that are only sent to the mobile phone (outbound only).

Shared Short Code

A Short Code that is shared with other content providers. “Keywords” are used to differentiate traffic.

Short Code 

Abbreviated mobile phone number, usually 4 to 6 digits, used as a destination address for 2-way messaging programs. Short codes can be “Dedicated” or “Shared”.


Short Message Service: also known as a ‘text message’, one SMS is made up of 160 characters maximum.

Two-way messaging Outbound messages with an inbound reply path to enable a 2-way conversation between application and person.


Virtual Mobile Number: also known as a ‘Long Code’ or a ‘Long Number’. This is a standard mobile telephone number that conforms to the numbering system in the relevant country and can be used for 2-way messaging.


Extensible Markup Language: MessageBird has an XML API to connect your application to our platform.