It’s obvious that the cost of an SMS is the main expense when it comes to sending messages globally. And you probably want to keep the costs to a minimum, but sometimes the price is already as low as it can get. So, you might think that you’re stuck with what you got. But there’s one option - phone number validation (also sometimes called number lookup).  

In this article, we’ll go over what exactly phone number validation is, how to use it, and how it will save your company money.  

What is phone number validation? 

Let’s say that your company has collected 10 000 phone numbers from customers and people who have opted-in to your messages. How do you know that these numbers are correct or haven’t been disabled later on?  

This is where phone number validation comes in. It validates each number to see if it’s still in use, what country it is in and what operator is used. It’s that simple, really.

How does it work?

When a phone number is put through the validation process, the API performs a “ping” at the operator’s database to see if the number is correct and live. The owner of the number doesn’t get any messages or notifications that this has been done, so it’s very incognito. 

Why should you use number validation? 

Keeping the contact database up to date is a constant struggle for most companies in the world. 77% of companies believe that false contact information affects their bottom line negatively, which I’m sure you can relate to. So, keeping an eye on the list of your customer’s phone numbers should be a priority. 

A high-quality phone number database can positively affect many parts of your business: 

  • It decreases your messaging costs - by filtering out the invalid numbers, you won’t waste money on sending them a message.

  • It prevents unexpected business costs - for example, when a package arrives at the parcel machine, the customer usually gets an SMS notifying them of the delivery. But when the number is invalid, two problems arise - first, the customer might get angry thinking that their package hasn’t arrived, although it’s in the machine. So, the support team must solve it.

Secondly, if a package stays in the machine for too long, the company has to move it back to the warehouse, which means more costs. Similar issues can be prevented with number validation in other industries, too.

  • Increases marketing ROI - your SMS marketing efforts will reach every customer in the database without wasting money on invalid numbers. 

How to use it? 

You have two options. Firstly, you can use your SMS service provider’s online platform to validate the numbers. It’s easy to do, but it can take some time to import the list and then export it.  

The second option, which we recommend, is to use an API (e.g. Messente's Number Lookup API, wink-wink) that you integrate with your own CRM. This way, the numbers are validated automatically, saving you time.  

Here’s an example of how to integrate it:

  1. User enters the phone number on your website
  2. Make an API call to Messente’s Number Lookup API
    1. Phone number is invalid
    2. Phone number is valid
  3. If the phone number is invalid (2.a) - show an error (save money!)
  4. If the phone number is valid (2.b) - send the SMS 

What is the cost of phone number validation? 

It’s low - about 1/10 the cost of an SMS per request. So, if you have 10 000 phone numbers and the average cost of validation is 0.002€ per number, the cost to validate all the numbers is 20€. 

What are the limits? 

As great of a tool that phone number validation can be, it has its limits. And there are two of them. First is GDPR - depending on the national regulator’s translation of the legal norms, number validation might be disabled for providers and used only by the operators themselves. 

On the other hand, it is more reliable in Europe. This is because most of Europe has national regulators, database handlers, etc. and the European operators are in close communication with them. Some countries outside of Europe might not have a portability database, and the information is out of date. Thus, when using the number validation tool, you might not get the correct information.  


Phone number validation is a valuable tool for any businesses who send SMS messages to their customers. It helps fight low-quality number databases and decreases business costs while being cheap to use. If your company’s customers are mainly based in Europe, it is a wise decision to start using it right away. You will be surprised how something as simple as that can have a significant impact on how you run things.