How to Build a Phone Number Verification Tool

by | Jul 4, 2023

Phone number verification is a process that businesses frequently use in their applications today. Businesses prefer this to keep data security at the highest level and reduce costs. There are many online verification phone number APIs and tools from which businesses and developers can obtain these services.

Verification phone number APIs and tools are web services that provide information on whether phone numbers are valid or not. These services provide detailed information about phone numbers as well as validation processes. This article will introduce you to the most popular phone number validation API that businesses use. Then we will develop an extremely fast and secure phone verification tool using this API.

The numverify API: Verify Phone Numbers Completely Free

home page of the numverify number validation api

The numverify API is a free phone number validator API. It supports phone numbers of 232 countries and provides data in JSON format.

This API provides high-accuracy data for 232 countries to its users. It offers data from international numbering plan databases. Additionally, it provides detailed information about phone numbers. such as carrier, geographical location, and line type data.

Lastly, this API can be easily integrated into all programming languages. In the unique documentation it provides, it is possible to find example integration codes for more than one programming language.

How do Build a Phone Number Validation Tool With the numverify API?

In this part, we will develop a number validation web application using the numverify API. With this application, we will receive the phone number and country code from the user as input. Afterward, we will query this information with the numverify API and print the response we get.

We need an API key to integrate and use the numverify API in any programming language. To obtain this API key, we will sign up for one of numverify’s innovative and flexible subscription plans. After registration, we will obtain our API key from a dashboard screen where we will also see the API usage.

After obtaining our API key, we are ready to develop our web application. Let’s open a file named ‘number-verification-tool-with-numverify.html’ in the file path where we want to develop the application and paste the following codes.

<!DOCTYPE html>
  <title>Phone Number Validation</title>
  <link rel="stylesheet" href="">
    .valid-icon {
      color: green;
    .invalid-icon {
      color: red;
    #validationResultTable {
      display: none;
    } {
      display: table;
  <div class="container">
    <h1>Phone Number Validation</h1>
    <form id="validationForm">
      <div class="form-group">
        <label for="numberInput">Phone Number:</label>
        <input type="text" class="form-control" id="numberInput" required>
      <div class="form-group">
        <label for="countryCodeSelect">Country Code:</label>
        <select class="form-control" id="countryCodeSelect" required>
          <option value="US">United States of America (+1)</option>
          <option value="GB">United Kingdom (+44)</option>
          <!-- Add more options as needed -->
      <button type="submit" class="btn btn-primary">Validate</button>

    <h2>Validation Result:</h2>
    <table id="validationResultTable" class="table">
          <td id="validField"></td>
          <td id="numberField"></td>
          <td>Local Format</td>
          <td id="localFormatField"></td>
          <td>International Format</td>
          <td id="internationalFormatField"></td>
          <td>Country Prefix</td>
          <td id="countryPrefixField"></td>
          <td>Country Code</td>
          <td id="countryCodeField"></td>
          <td>Country Name</td>
          <td id="countryNameField"></td>
          <td id="locationField"></td>
          <td id="carrierField"></td>
          <td>Line Type</td>
          <td id="lineTypeField"></td>

  <script src=""></script>
  <script src=""></script>
    document.getElementById('validationForm').addEventListener('submit', function(event) {
      var number = document.getElementById('numberInput').value;
      var countryCode = document.getElementById('countryCodeSelect').value;

      // Make API request
        .then(response => response.json())
        .then(data => displayValidationResult(data))
        .catch(error => {
          alert('An error occurred while validating the phone number.');

    function displayValidationResult(response) {
      document.getElementById('validField').textContent = response.valid;
      document.getElementById('numberField').textContent = response.number;
      document.getElementById('localFormatField').textContent = response.local_format;
      document.getElementById('internationalFormatField').textContent = response.international_format;
      document.getElementById('countryPrefixField').textContent = response.country_prefix;
      document.getElementById('countryCodeField').textContent = response.country_code;
      document.getElementById('countryNameField').textContent = response.country_name;
      document.getElementById('locationField').textContent = response.location;
      document.getElementById('carrierField').textContent = response.carrier;
      document.getElementById('lineTypeField').textContent = response.line_type;

      var validationResultTable = document.getElementById('validationResultTable');

Before running the above application, let’s paste our own API key into the ‘YOUR-API-KEY’ field. When we run the application, the following screen will meet us.

default page of the phone number verification application

The country code dropdown has ‘US ‘and ‘GB’ values as an example. We can extend this dropdown with 232 country codes supported by the numverify API.

To test the application, let’s click on the validate button after filling in the phone number and country code fields. After this process, we will get the following result table.

result page of the phone number verification application

With this application, we have developed a very fast and secure phone number verification tool using the numverify API.

Sign up free - Numverify phone number verification API


Today, phone number validation processes have become very important for businesses. The increasing importance of data has led to revolutions in data security. The fastest and easiest way for businesses to add a data security step is to use a number verification tool. Businesses can also use the services that provide this tool today, or they can easily use the number verification API on their own systems.

Integrate our free number verification API into your projects, and easily increase the security of your customers’ data


Q: Can I Use Third-Party Services or APIs for Phone Numbers Verification?

A: Yes, you can. Today, there are many third-party services and APIs that provide the phone number and sms verification.

Q: Why Do Businesses Need to Validate Phone Numbers?

A: It is very important for businesses to do phone validation. By doing this, businesses can both increase security and prevent financial loss by detecting invalid phone numbers. Businesses can always keep customer records in databases with high accuracy.

Q: How Does Phone Validation Work with an API?

A: A phone validation API provides businesses with information on whether a phone number is valid or not. For this, it takes the phone number and generally the country code as parameters for the endpoint they provide to their users. Then, it inquires about this phone number from the official telecommunications companies of the countries and obtains the necessary information.

Q: Is the numverify API a Personal and Business Numbers Validation API?

A: Yes, it is. The numverify API is a web service where users can validate both personal and business numbers. Supports 232 country phone numbers.