What is HLR and why is it important for SMS routing?


The Home Location Register (HLR) is the main database of the permanent subscriber information for a mobile network. This information includes the validity of a phone number, which network it is operating on, confirming whether or not the number has been ported, the network that originally issued the number, and information on whether or not the number is roaming.

The HLR plays an important role in SMS (as well as voice) routing, because it provides information to where the text message should be routed. To gather this information in A2P messaging, SMS providers like tyntec look up the HLR prior to sending the message to find out how to best route it. This is the “number lookup” (also known as HLR lookup, number query, etc.).

Enterprises that work with several communications providers may need to look up the phone numbers with a specialist like tyntec, making sure that SMS messages are routed and delivered appropriately.

Check our Number Information product page for more information.