Using Phone Number Lookup Free to Autofill Web Forms

by | May 9, 2024

Users today want to get things done quickly on websites, be it navigating to their desired web page or filling out a web form. Especially, when it comes to filling web forms, many users find it a time-consuming and boring task. This is where auto-filling web forms and phone number lookups come in. Auto-filling web forms means populating the fields within forms with relevant data automatically without manual input from the user. This data can include information such as name, address, phone number, email, etc. A free phone number lookup tool makes it easier to integrate the autofill web forms functionality into your website or web app. It also serves as a powerful tool to prevent fraud by verifying and validating numbers. 

No matter what purpose you’re using the phone number lookup tool for, it’s essential to choose a reliable number lookup tool that provides accurate results. 

In this article, we’ll show you how you can easily use a phone number lookup free to autofill web forms. We’ll be using numverify global phone number validation and lookup API in our coding examples. The reason for choosing numverify is that it is widely recognized for its high data accuracy, be it for number verification, line and carrier detection, or location data associated with the provided number. 

What Does Phone Number Lookup Mean?

Phone number lookup means finding the information associated with a given phone number. This information can include line type, carrier, and location data. However, some tools also show the owner’s name.

Some of the use cases that businesses perform with this data are as follows:

  • Obtaining User Information Automatically: This is the most common use case of phone number lookup free. With a phone number lookup tool, businesses can access detailed information from the phone numbers of their users. For example, companies can automatically obtain a user’s country and location data from the phone number they provided during the registration process in a web app. 
  • Number Verification: Advanced tools like numverify also allow users to verify and validate phone numbers. This helps maintain a clean database for marketing purposes and prevent fraud. For instance, e-commerce businesses can verify if a customer has provided a genuine phone number to identify fake orders and prevent scams.
  • Extra Cost Prevention: With a reverse phone lookup service, businesses can easily reduce their costs, such as those associated with calling or sending SMS. With this service, businesses can detect non-valid cell phone numbers in bulk SMS sending and exclude these cell phone numbers from the list. 

Using a Phone Number Lookup Free API to Autofill Web Forms

A graphic showcasing the use of reverse lookup to autofill web forms

In this section, we will show you how to autofill web form fields with a phone number lookup free API. We’ll use the numverify API in our coding example as it’s the leading and most accurate number lookup API today. 

Here, we’ll create a simple registration form that will ask for the user’s name and number. Then based on the number provided by the user, the rest of the form will be filled automatically. This will include the location, country name, country code, and line type associated with the provided phone number. 

You can use this functionality in different types of web forms, such as registration forms, order forms, survey forms, etc. Auto-filling web forms significantly enhances the user experience and saves time. 

Let’s get started!

Get a Free API Key

Before we start developing the application, we need an API key to use the numverify number lookup API. To get your API, you need to sign up with numverify and create an account. You’ll then find your unique numverify API key and API usage information in your dashboard. 

Numverify offers a free plan and various paid subscription plans. You can choose any of these plans based on your app’s requirements.

subscription plans of the numverify phone number lookups API

Writing the Code

Now, let’s develop our application. First, let’s create a file named ‘autofill-web-forms-with-numverify.html’ in the file path where we will develop the application. Then, put the following codes in the file:

<!DOCTYPE html>

<html lang="en">


  <meta charset="UTF-8">

  <meta name="viewport" content="width=device-width, initial-scale=1.0">

  <title>Autofill Web Forms App</title>

  <link rel="stylesheet" href="">


    body {

      background-color: #f8f9fa;


    .container {

      margin-top: 50px;





  <div class="container">

    <div class="row justify-content-center">

      <div class="col-md-6">

        <h2 class="mb-4">User Registration</h2>

        <form id="verificationForm">

          <div class="form-group">

            <label for="firstName">First Name:</label>

            <input type="text" class="form-control" id="firstName" required>


          <div class="form-group">

            <label for="lastName">Last Name:</label>

            <input type="text" class="form-control" id="lastName" required>


          <div class="form-group">

            <label for="phoneNumber">Phone Number:</label>

            <input type="tel" class="form-control" id="phoneNumber" required>


          <button type="button" class="btn btn-primary" id="continueBtn">Continue</button>





  <div class="container mt-5 d-none" id="registrationForm">


      <div class="form-group">

        <label for="location">Location:</label>

        <input type="text" class="form-control" id="location">


      <div class="form-group">

        <label for="countryName">Country Name:</label>

        <input type="text" class="form-control" id="countryName">


      <div class="form-group">

        <label for="countryCode">Country Code:</label>

        <input type="text" class="form-control" id="countryCode">


      <div class="form-group">

        <label for="lineType">Line Type:</label>

        <input type="text" class="form-control" id="lineType">


      <button type="button" class="btn btn-success">Save</button>




    document.getElementById('continueBtn').addEventListener('click', function () {

      const firstName = document.getElementById('firstName').value;

      const lastName = document.getElementById('lastName').value;

      const phoneNumber = document.getElementById('phoneNumber').value;


        .then(response => response.json())

        .then(data => {

          document.getElementById('location').value = data.location;

          document.getElementById('countryName').value = data.country_name;

          document.getElementById('countryCode').value = data.country_prefix;

          document.getElementById('lineType').value = data.line_type;





        .catch(error => {

          console.error('Error fetching data:', error);

          alert('An error occurred during phone number validation. Please try again.');






When we run the application with this code, we will get the user’s name, surname, and phone number information from the user at the user registration stage. After entering this information, the user will press the ‘Continue’ button and will see that the fields in the other form that opens are automatically filled.

Remember to replace ‘YOUR-API-KEY’ with your actual API key before running the application.

Learn how to build a phone validator app using the numverify API with PHP!

Testing the App

When we run the application, it’ll show the following default:

demo of user registration app created using a free phone number lookup API

Let’s fill out this form:

demo of user registration app created using a reverse phone number lookup API

After pressing the ‘Continue’ button, we see that the fields such as location, country name, country code, and line type are automatically filled in the new form opened. This means the user doesn’t have to enter this information manually.

auto-filled form of the user registration app

Why We Chose numverify Number Lookup API

home page of the numverify  number validator and phone number lookup free API

Numverify is one of the leading phone validator and number lookup APIs on the market today. The API is known for its high accuracy in phone number validation, line type detection, carrier detection, and location data. Thus, it’s a dependable phone number lookup free source.

Here are the key features of numverify:

  • It supports phone numbers from 232 countries.
  • Numverify supports both local and international phone numbers and provides real-time responses.
  • The numverify API has extensive documentation containing detailed usage instructions and code examples in different programming languages. 
  • Numverify is a free phone number lookup API.  Its free plan offers 1000 monthly API requests. Numverify also has multiple paid subscription plans with more monthly calls and advanced features.
  • Numverify also provides accurate location data associated with a given phone number. The API offers an incredible dashboard to its users. With this dashboard, users can track their API usage on a daily or monthly basis. They even receive automatic notifications if their API usage decreases.

How to Use the numverify Phone Number Lookup Free API to Autofill Web Forms?

Numverify provides accurate location data associated with a given phone number. This includes the country name, country code, and city. As we did in our example application, you can use numverify free reverse phone lookup to automatically populate location-related fields in registration, order, and survey forms based on the phone number provided by the user. Auto Filling forms not only saves time but also enhances the user experience. 


Auto-filling web forms is a common practice that helps save users’ time and enhance the user experience. A phone number lookup free tool like numverify can help with that. For example, numverify provides location data associated with a phone number. This means you can use numverify to populate location-related data automatically in forms based on the phone number provided by the user. We’ve created an app with similar functionality in this article.

Use the best phone number lookup API and get detailed information on phone numbers of 232 countries in JSON format!


Is there a free way to look up a phone number?

There are various online tools that offer phone number lookup free features. However, if you’re looking to integrate the functionality into your website or web app, you can use the numverify API to get phone carrier, line type and location data associated with a phone number for free.

How do I get details of a number?

You can use a phone number lookup free tool like Truecaller or an API like numverify to get details associated with a phone number.

How to check the phone number owner?

Apps like Truecaller show the name of the owner associated with an unfamiliar phone number. However, always remember to respect privacy laws and use phone number lookup free responsibly.

What are the differences between the numverify API and other reverse phone lookup services?

The numverify API has many important features that distinguish it from its competitors. First of all, it supports phone numbers from more than 230 countries. It also provides detailed information such as line type, carrier, country name, and country code for valid phone numbers. Finally, it has a free subscription plan offering 1,000 API calls per month.

What are the best use cases of the numverify API?

Some prominent use cases of the numverify API are as follows:

  • Phone Number Verification
  • Auto filling Web forms
  • Spam Detection
  • Analysis and Marketing
  • Developing Marketing Strategies