Home Location Register

What Is the Home Location Register?

The Home Location Register (HLR) is a database that stores details relating to every cellphone number connected to the Global System for Mobile Communications (GSM) network across the world. With over 5 billion unique mobile phone users, it’s an extensive source of data.

The Home Location Register stores data including:

• network provider details
• location (country)
• country code
• telephone number(s)
• whether the number is active or invalid
• whether the number is in roaming
• the International Mobile Subscriber Identity (IMSI)
• the Mobile Station International Subscriber Directory Number (MSISDN)

Some of the data flowing to and from the HLR makes use of the SIM card in the device.

Various companies offer services that give people the ability to query the HLR database, for purposes including fraud prevention, data cleansing, marketing and compliance.

How Does HLR Lookup Work?

HLR lookup works as follows:

1. A company requests a lookup on a specific number. This would usually be via a third-party company or provider.
2. The provider queries the HLR database, via a mobile network operator.
3. The database returns the available information.
4. The information is provided to the original requestor.

The process takes just seconds for an individual lookup. Depending on both local privacy laws and the nature of the service being provided to the end-user, the requesting party may receive all available HLR data or just a subset of it.

While some services offer Home Location Register lookup for one number at a time as part of a reverse phone lookup, others provide more sophisticated solutions. These can include:

• bulk lookups for large batches of numbers at one time – which is especially useful for marketing and data clean-up and validation
• API integration used to automate the checking of the HLR database alongside other business processes

Who Maintains the Home Location Register?

The Home Location Register is collectively maintained by every global mobile operator that provides 2G and 3G cellular services in particular. In turn, these companies also play a part in facilitating lookups, usually charging a nominal fee to third parties for each call. Different services exist for 4G and 5G.

HLR Lookup Examples and Use Cases

Let’s take a look at some examples of HLR lookup while exploring various use cases:

Data Cleansing

Marketing via mobile devices, with cold calls and SMS messages, is popular but can be costly. Many cellphone numbers are not actively used or they have been allowed to go dormant – and many more are never activated and used once they’re issued. One study, for example, found that only two-thirds of issued numbers had been activated in India.

By performing bulk HLR lookups against their marketing lists, companies can filter out inactive numbers, ensuring budget isn’t wasted on text messaging or calling unused numbers.

Fraud Prevention

HLR lookups can help companies verify that people are where they say they are and that they’re providing legitimate and active mobile numbers.

In fact, the Home Location Register can even enable fraud investigators and other interested parties to determine whether a SIM card has been swapped. SIM swapping is a common practice among fraudsters.

Spam Prevention

Companies offering online signups can use an HLR lookup to help validate the details of people provide. They can also identify when someone attempts to use fake numbers instead of providing their own.

It’s worth noting that while there are plenty of legitimate uses for HLR lookups, they can also be abused. Spammers and fraudsters, for example, use HLR functionality to build their own lists of potential targets.

Why Is HLR Lookup Important?

The Home Location Register database provides a rich source of data on cellphone numbers across the world. It allows companies to access a comprehensive set of information from a single data point and a relatively simple and straightforward way to validate and cleanse other databases.

How Does HLR Lookup Fight Fraud?

HLR lookups can help to fight fraud, especially when it’s used alongside other data enrichment techniques, device fingerprinting, velocity checks and behavioral analysis. It can be invaluable in assessing the overall risk level of a customer.

For example, HLR lookup can answer questions such as:

• Is this customer in their normal location (or roaming overseas)?
• Is this an established number, connected to a normal network, or a virtual throwaway number?
• Is the mobile number this customer has provided active and current?

Using API integrations and automation, HLR lookups can be incorporated into fraud prevention techniques in a transparent way, with checks taking place near-instantly.