How To Build A Phone Number Validator In Javascript

by Business 07 June 2023

Build A Phone Number Validator In Javascript

Do you want to avoid using incorrect or invalid phone numbers in your web applications? Building a phone number validator in JavaScript can be the solution you’ve been searching for. In this blog, we will explore what a phone number validator is and why it’s beneficial to build one using JavaScript. Moreover, you will also learn about the importance of phone number validation.

A phone number validator is a tool that verifies whether a given phone number is valid or not. It helps ensure that users enter correct and properly formatted phone numbers, preventing issues down the line. A phone number validation can improve user experience and data accuracy for businesses.

But can we make use of APIs to simplify the process? We’ll delve into this question and examine the possibilities of using APIs to build a phone number validator in JavaScript. APIs can provide valuable services for validating phone numbers, making the development process more efficient and effective.

Join us on this journey as we explore the world of phone number validation in JavaScript and empower you to create robust and user-friendly web applications.

What Is A Phone Number Validator?

A phone number validator is a tool or function that checks the validity and correctness of a phone number. It ensures that the phone number a user enters follows the required format and is an actual, reachable number. Here are a few examples of what a phone number validator can do:

Format Validation.

It verifies whether the phone number adheres to a specific format, including country codes, area codes, and proper number lengths. For instance, a validator might ensure that a U.S. phone number begins with “+1” and consists of 10 digits.

Syntax Validation

It checks for the correct syntax and character usage in a phone number. This includes validating the presence of dashes, parentheses, or spaces in the appropriate places.

Region-Specific Validation

Some validators can determine if a phone number is valid for a specific country or region, which involves checking against known numbering plans and rules.

Reachability Validation

Advanced validators may further verify if the phone number is active and reachable by making API calls to telecom providers.

Using these validation techniques, a phone number validator can help ensure data integrity. Hence, it can prevent user errors and enhance the user experience when working with phone numbers in web applications.

What Are The Benefits Of Building A Phone Number Validator In Javascript?

Building a phone number validator in JavaScript offers several benefits for web developers. Here are some of the advantages:

A phone number validator helps maintain accurate and reliable data by ensuring users enter valid phone numbers. This eliminates errors and inconsistencies in the data collected through forms or user inputs.

By validating phone numbers in real time, you can provide immediate feedback to users if they enter an incorrect or improperly formatted number. This improves the user experience by reducing frustration and streamlining the data entry process.

Validating phone numbers helps prevent errors and avoids issues arising from incorrect or invalid numbers. This can include failed communications, undelivered messages, or issues with phone number-dependent functionalities.

By validating phone numbers upfront, you save time and resources that would otherwise be spent manually verifying or correcting data later. This is particularly beneficial when dealing with large datasets or integrating third-party services requiring accurate phone numbers.

You can control the validation rules and customization options when building your phone number validator in JavaScript. You can tailor the validator to specific formatting requirements, regional standards, or any additional validation criteria relevant to your application.

A phone number validator can be seamlessly integrated into other features or functionalities within your web application. This includes user registration, contact forms, phone number verification, or any other process that relies on accurate phone number inputs.

Can We Use Apis For Building A Phone Number Validator In Javascript?

Yes, you can leverage APIs to build a phone number validator in JavaScript. APIs provide a convenient way to validate phone numbers by utilizing external services and databases. Here are a few popular APIs that you can use for phone number validation:

Numverify API

Numverify offers a simple RESTful API that allows you to verify phone numbers worldwide. It provides data such as the country, location, carrier information, and line type of a given phone number. You can request HTTP to their API endpoint and receive JSON responses with the validation results.

Google’s libphonenumber API

Google’s libphonenumber is a powerful library for parsing, formatting, and validating phone numbers. It is available in various programming languages, including JavaScript. You can utilize the library’s JavaScript version or use Google’s libphonenumber API, which provides an HTTP-based API for phone number validation.

Twilio Lookup API

Twilio is a widely used platform for communication services, and its Lookup API offers phone number validation as one of its features. It provides information about the carrier, line type, and country of a given phone number. You can make API requests to Twilio’s Lookup API and receive JSON responses containing the validation details.

Twilio Lookup API

Nexmo Number Insight API

Nexmo, now part of Vonage, offers a Number Insight API that provides phone number validation and intelligence. It provides data such as carrier information, line type, and real-time phone number validation. The API supports multiple programming languages, including JavaScript, making it suitable for building phone number validators.

Nexmo Number Insight API

How To Build A Phone Number Validator By Using Javascript API?

Building a phone number validator using a JavaScript API such as Numverify is simple. Here is an example request by Numverify to build a phone number validator.
    ? access_key = YOUR_ACCESS_KEY
    & number = 14158586273

Here is the JavaScript code for building a phone number validator:

// set endpoint and your access key
var access_key = ‘YOUR_ACCESS_KEY’;
var phone_number = ‘14158586273’;

// verify phone number via AJAX call
    url: ‘’ + access_key + ‘&number=’ + phone_number,  
    dataType: ‘jsonp’,
    success: function(json) {

    // Access and use your preferred validation result objects



Building a phone number validator in JavaScript can greatly enhance your web applications’ accuracy and user experience. You can easily integrate phone number validation capabilities into your JavaScript code by leveraging APIs such as Numverify, Google’s libphonenumber, Twilio Lookup, or Nexmo Number Insight.

Whether it’s ensuring correct formatting, verifying region-specific rules, or checking reachability, a phone number validator helps maintain data integrity and prevents errors. With step-by-step guidance and the flexibility to customize the validation rules, you can create a robust and user-friendly phone number validator that streamlines data entry and enhances the functionality of your web applications.


Can A Phone Number Be Verified?

A phone number can be verified using various methods and services, including phone number validation APIs.

Is The Phone Validator Free?

The availability and cost of phone validators vary. Some APIs offer free tiers, while others may have paid plans.

How Do You Check Phone Numbers?

To check phone numbers, use a phone number validator or API service for validation and verification.

How Do You Check If A Number Is Real?

You can use APIs like Numverify, Twilio Lookup, or Nexmo Number Insight to check if a number is real.

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Author Bio: Abdul Aziz Mondol is a professional blogger who is having a colossal interest in writing blogs and other jones of calligraphies. In terms of his professional commitments, he loves to share content related to business, finance, technology, and the gaming niche.

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