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Number Lookup, also known as Home Location Register (HLR), determines the country of origin and the home network of a mobile subscriber. It can also be used to find the country a subscriber is currently roaming. The service supports all GSM networks worldwide. Number Lookup is normally used together with SMS Delivery and SMS Billing to check what network you should send the messages to. It can also be used to check if a subscriber is reachable or if the user is not available (i.e., has switched off the phone).

The benefits of a number lookup service for a business that manages a customer or subscribers database are invaluable. Number Lookup offers instant insight on subscribers’ information, with fast queries in real-time, without the need for any application implementation. Not to mention that it holds a low cost per query. Number lookup when efficiently used can even upgrade a company’s verification and fraud detection services, providing subscribers’ identification data (IMSI).

There are two ways to perform a successful Number Lookup, synchronous and asynchronous. Let us further examine both types to assess which one can fit better for your dev projects.

Synchronous vs. Asynchronous Number Lookup

Synchronous Number Lookup functions over HTTP API as soon as a client sends a number lookup query, single or multiple. If you make many simultaneous synchronous number lookups you will have to wait until every single lookup is completed. This may lead to a queue if you have to check a big list of numbers. Make note that the synchronous REST HTTP API responses that you receive by looking up numbers are sent after each single or bulk request. Responses are visible in just a matter of seconds.

However, the period between sending a request and receiving a response can be extended due to various issues (e.g., the limited number of requests that mobile operators can process in a fixed period). This does slow down the response delivery for the entire lookup request, as every query gets completed as soon as the last number of the specific query is processed.

Asynchronous Number Lookup is performed over a dedicated notify URL set by a client and operates differently from the synchronous number lookup. With asynchronous Number Lookup, you can send as many requests as you want, without having to wait for all of them to complete. You receive a notification on your notifyURL as soon as every request is obtained. Depending on the mobile operator, you may receive the entire bulk list of requests all at once or every number by itself. A quite convenient procedure especially if you have a large phone number database or multiple databases.

Asynchronous API improves the delivery speed because you receive real-time notifications. Apart from speed, the asynchronous type of number lookup is also more complicated to integrate than the synchronous. The client is required to have a call-back server to parse the response with the particular request. In this case, security is highly important, so we strongly advise that your customer sets up a secure firewall for data protection.


Integrating Number Lookup with your dev projects

Depending on the project you want to design and implement, Number Lookup will help you clean and preserve a valid number database. Especially if you have a multitudinous database, you will be able to instantly identify unused or inactive numbers, saving valuable implementation time.

Besides, you can easily resolve portability issues of any phone number regardless of the company type you build your project for and optimize the messages and voice routing. Last but certainly not least, number lookup will provide you with invaluable roaming information for optimized routing. If you build projects for the financial sector, this functionality will immensely contribute to fraud prevention and secure verification of users.

Leverage the failover functionality of an intelligent omnichannel solution that comprises several number solutions that you can use in combination with your number lookup service to build a complete number authentication process. In case your SMS flow is unable to complete the process, you can harness the failover functionality. Complete a number verification using an interactive voice response (IVR) system, any messaging app, a missed call service, push notification, and so on.

Especially for newly developed projects that have a progressive growth rate, even a small rate of wrong numbers could translate into millions of failed verifications and lost users. It goes without saying that verified users are easier to reach, easier to support, and offer a sense of security on the app or service. For projects that involve SMS-based 2-factor authentication (2FA) solutions for security or account validation, effective number lookup can help maximize conversion rates and provide the best possible customer experience for users.

3 different ways to perform Number Lookup

You can use three different methods to perform Number Lookup for phone numbers. One by one using a business phone number lookup tool, bulk upload of numbers via CSV, or through a simple and powerful API. With an API integration like Routee’s Number Lookup, you can even incorporate the carrier lookup into your own system and validate contact information without having to log in to your Routee account. Also, you can easily perform a bulk

How to perform mass HLR lookup via Routee?

1. Log in to your Routee account and go to the “Look Up” Section.
2. Click “Send Request" and upload your .xls or .csv file.
3. Click the checkbox “ported” if your client wants ported info, if not proceed to step 5.
4. Click “Proceed".
5. On “additional email", add your email address so you can receive the results and be able to share them with the client.
6. Click “Proceed" and you are all set.

Final thoughts

First things first, planning is everything. To decide the most fitted number lookup solution (synchronous vs asynchronous) for your project you need to lay down the project’s specifics first. Will you be using number lookup only to check the status of mobile numbers, to see which numbers are active, switched on, and which ones are unavailable?

Will the service be used to increase sales conversions of a company’s sales department or to provide better customer service to existing clients? Maybe the company wants to make its SMS marketing campaigns more cost-effective by not sending text messages to inactive phones that will only increase the company’s expenses.

Will you need to integrate the service with the company’s SMS platform to comply with GDPR regulations? Or does the company need this service to check in real-time the validity of a number entered on its website? Maybe the company needs to integrate the Number Lookup service with a verification flow.

You need to address all these questions and then decide on which road you will choose to implement your project. If you need further expert assistance, Routee’s experts are always available to help you out with the best possible workflow for your own project. Make sure to visit Routee’s API docs section for more interesting information about Number Lookup.

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