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How to use the HLR mobile number verification service

10 minutes of reading
Publication: 05.26.2023
Última modificación: 06.30.2023


HLR or Home Location Register is a telephone database validation service. It lets you know if a mobile number exists, which telecom operator it belongs to and if it is connected to the right subscriber. 

HLR queries help you analyze your database and identify inactive or invalid numbers. That is, it is possible to find out which mobile numbers correspond to current mobile subscribers.

Checking a phone number in HLR is legal, because the information contained in this registry is publicly accessible and does not contain personal data. Of course, the HLR system also complies with the provisions of the GDPR and data privacy directives. 

This will make your SMS campaigns and sendings 100% effective, as you will only send SMS messages to valid recipients. You will get better results in your sendings (more openings and clicks) and you will save unnecessary expenses in messages that would generate errors due to inactive or non-existent numbers.

Benefits of the HLR service

The benefits of using this service are multiple. Here are some of them:

  • Increased effectiveness of the marketing strategy 
  • Optimization of SMS traffic
  • Decreased typing or data entry in cell phone fields
  • Updating of invalid numbers
  • Optimization of SMS cost if you have providers with different prices per carrier
  • Reducing the cost of sending SMS messages

Therefore, the HLR service is a highly recommended tool to maximize the efficiency of communications and reduce associated costs. The result is an updated and accurate database of numbers.

Use cases

The HLR service can be used in two areas:

  1. To clean up contact databases: discarding invalid, incorrectly formatted, inactive, duplicate or deactivated numbers. Even those that have been inactive for a long time can be discarded. Each HLR query has a cost and therefore it is necessary to calculate the benefit of performing this check especially in very outdated databases.

            The HLR check can be performed:

    1. When you receive data from a new database and want to check if the cell phone data is current and active. This applies to both SMS and phone calls.
    2. It is also advisable to perform this action from time to time (every 2-3 years) to detect those numbers that are not active in a database and in that case ask the recipients to update their mobile number through other channels. It is estimated that between 2% and 5% of numbers change every year. Therefore, in this way we are preserving the validity and updating a database of maximum efficiency.

  1. On-the-spot online check: you will be able to know the status of the number and its carrier. This information is very useful to perform an HLR query after a user has entered a mobile number. Otherwise the user should be asked to enter a valid number because he/she has probably made a mistake. This usage can be used:

    1. Authentication processes before sending the OTP code.
    2. Before verifying a cell phone associated with a user account.
    3. In any data form that accepts a cell phone (such as in an online order).

Cost of the HLR service

HLR queries have a reduced and unique cost regardless of the country of the mobile number. Therefore, it is necessary to calculate whether the cost of an HLR check is higher than the cost of an SMS and thus discard the number if the SMS generates an error due to the wrong destination number.

Moreover, it is necessary to estimate if a database or a use case has a number of wrong phones to apply a massive HLR check. In many cases it is enough to obtain the results of a first SMS sending and update the database with the errors obtained.

In general, it is advisable to perform a previous HLR check if the number of errors or incorrect numbers is estimated at 15% or higher.

However, in cases where it is decided to send an SMS and update the database or registry with the result (error or delivery confirmation). We recommend not to discard the numbers in the first error as it may be due to multiple reasons (such as temporary network errors, device errors, etc.) and valid numbers would be discarded. In this case we recommend performing an HLR query only to those SMS messages that have generated an error to confirm that they are inactive numbers.

How does the HLR service work?

The first step is to register an account on the LabsMobile platform. Once the account is created, it is possible to access the HLR service from the WebSMS application or through the LabsMobile API.

  • HLR in the WebSMS application. By means of a simple form where you can enter numbers you can know who are active and all the related information. This option is recommended in case you want to check a database because it can be imported into the WebSMS account and perform the HLR check of a whole group of contacts by downloading the results.
  • The LabsMobile HLR API allows immediate querying and thus integrating this service with any application or system. This method is the most suitable when you want to perform the query in OTP processes, data validation of a form or when you want to interact with the user when he enters his mobile number.

In conclusion, the HLR service is highly effective for all companies or entities that send SMS or make phone calls and want to increase the efficiency of their actions and communications.

Our team advises you

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