Discover how to validate phone numbers using Joi with practical code examples for your website`s success

Table of content

  1. Introduction
  2. What is Joi?
  3. Why validate phone numbers?
  4. Setting up Joi for phone number validation
  5. Joi phone number validation rules
  6. Practical code examples for phone number validation
  7. Common errors and how to troubleshoot them
  8. Conclusion


If you're creating a website that involves collecting phone numbers from users, you probably want to ensure that the phone numbers they provide are valid. There's nothing more frustrating than trying to contact someone only to find out that the phone number you have is incorrect or incomplete. Thankfully, there are tools available that can help you validate phone numbers and ensure that they're formatted correctly.

One such tool is Joi, a JavaScript validation library. Joi makes it easy to validate a variety of data types, including phone numbers. With Joi, you can specify the format and requirements for the phone numbers you're looking for, and Joi will ensure that any phone numbers submitted by users meet those requirements. This can help you avoid issues with incorrect or incomplete phone numbers and make it easier for you to contact users when necessary.

In this article, we'll explore how to use Joi to validate phone numbers, and we'll provide some practical code examples to help you get started. We'll also discuss some best practices for validating phone numbers, including common formats and requirements you may want to consider. By the end of this article, you'll have a better understanding of how to use Joi to validate phone numbers on your website, and you'll be well on your way to building a more effective and efficient user experience.

What is Joi?

Joi is a powerful data validation library for Node.js. It allows users to easily validate and sanitize input data when building web applications. Joi's syntax is easy to use, and its features include support for complex validation requirements such as nested objects and arrays, custom validators, and conditional validation.

One of the most useful features of Joi is its ability to provide detailed error messages that pinpoint exactly where validation errors have occurred. This makes debugging and troubleshooting much easier than trying to sift through verbose error messages or parsing tons of logs.

Joi has gained a lot of popularity due to its ease of use and the strong ecosystem around it. It's widely used in various frameworks such as Hapi and Nest.js, and it's also compatible with various types of data, including JSON, forms, and query strings.

Overall, Joi provides a flexible and powerful way to validate input data in your web application. Whether you're building a small pet project or a large-scale application, Joi can help you ensure that your data is consistent and error-free.

Why validate phone numbers?

Validating phone numbers is an important aspect of web development, especially when it comes to user input. Phone numbers can come in various formats, including international formats, and can include additional or missing digits. Failing to validate phone numbers can lead to inaccurate data, bad user experience, and even security risks.

Validating phone numbers can also benefit your website's success. Accurate phone numbers can be used for various purposes, such as sending text messages or making phone calls directly from the website. Additionally, phone numbers can be used to provide location-based information, which can enhance the user experience and make the website more user-friendly.

By using the Joi validation library, you can validate phone numbers and ensure that they adhere to a specific format. This can be done easily with practical code examples and can save time and resources in dealing with inaccurate or incomplete data. In summary, validating phone numbers is a crucial step in web development that can improve user experience, data accuracy, and website success.

Setting up Joi for phone number validation

Joi is a powerful, easy-to-use validation library for JavaScript. With Joi, you can easily validate user inputs and ensure that they meet the requirements you set. is simple and straightforward. Here's how you can do it:

  1. Install Joi: First, you'll need to install Joi using NPM or Yarn. Open your terminal or command prompt and run the following command:

npm install joi

  1. Create a validation schema: Once you have installed Joi, create a validation schema for the phone number. In this schema, you can set the rules for the phone number validation, such as the minimum and maximum length, the allowed format, and more. Here's an example:
    const phoneSchema = Joi.string().min(10).max(15).pattern(/^[\d()-\s]+$/); ```

In this schema, we have defined that the phone number should be a string with a minimum length of 10 and a maximum length of 15. We have also set a pattern using a regular expression to allow only digits, spaces, dashes, and parentheses.

3. Validate the phone number: Using the created schema, you can validate the phone number. Here's an example:

``` const phoneNumber = '123-456-7890';
    const { error, value } = phoneSchema.validate(phoneNumber); ```

In this example, we have passed a phone number to the `phoneSchema.validate()` method, which will return an object with an `error` property if the phone number is invalid, and a `value` property if it is valid.

By , you can ensure that your user inputs are accurate and meet your requirements. With Joi, validating user inputs has never been easier!
<h3 id="joi-phone-number-validation-rules">Joi phone number validation rules</h3>

Joi is a powerful validation package that can be used to validate phone numbers in JavaScript. It provides several out-of-the-box rules that can be used to ensure that phone numbers entered by users are formatted correctly and follow certain patterns.

One of the most common rules that can be used with Joi for phone number validation is the "pattern" rule. This rule can be used to match a phone number against a regular expression, ensuring that it follows a specific format. For example, a common pattern for US phone numbers is "###-###-####", where each "#" represents a digit.

Another useful rule is the "length" rule, which can be used to ensure that a phone number is a certain number of digits long. For example, a US phone number should be 10 digits long (including the area code). By using the "length" rule with a value of 10, we can ensure that all phone numbers entered by users are the correct length.

Joi also provides several other useful rules for phone number validation, such as "min" and "max" for numeric values, and "allow" and "deny" to allow or disallow certain characters in the phone number.

By using these rules with Joi, we can create a powerful validation system for phone numbers in our websites and applications. This can help us ensure that user input is accurate and consistent, improving the overall user experience and reducing errors and confusion.
<h3 id="practical-code-examples-for-phone-number-validation">Practical code examples for phone number validation</h3>


When it comes to validating user input on your website, one of the most common fields that requires validation is the phone number field. Validating phone numbers can be tricky due to the different formats and conventions used in different countries. However, with Joi, a schema validation library for JavaScript, validating phone numbers is a breeze.

Joi provides a `phone()` method that allows you to validate phone numbers based on their format in different countries. For example, to validate a phone number in the United States, you can use the following code:

const Joi = require('joi');

const schema = Joi.object({
phone: Joi.string().phone({
format: '###-###-####',
country: 'US',
strict: true,

In this example, the `phone()` method is called on a string schema to validate the phone number field. The `format` option specifies the format of the phone number, which in this case is `###-###-####`. The `country` option specifies the country code for the phone number, which in this case is `US`. The `strict` option ensures that only valid phone numbers are accepted.

Joi also allows you to validate phone numbers using regular expressions. For example, to validate a phone number that starts with `+1` (the country code for the United States), you can use the following code:

const Joi = require('joi');

const schema = Joi.object({
phone: Joi.string().regex(/^+1\d{10}$/),

In this example, the `regex()` method is called on a string schema to validate the phone number field using a regular expression. The regular expression `/^\+1\d{10}$/` matches phone numbers that start with `+1`, followed by 10 digits.

In conclusion, using Joi to validate phone numbers can help ensure that your website's user input is accurate and consistent. By providing , you can improve the user experience on your website and reduce errors and inconsistencies in your data.
<h3 id="common-errors-and-how-to-troubleshoot-them">Common errors and how to troubleshoot them</h3>

One common error when validating phone numbers using Joi is not accounting for country codes. Phone numbers can vary greatly depending on the country they originate from, and validation should be tailored accordingly. For example, a common practice is to add a "+" sign before the country code, which can be achieved using the Joi.string().regex() method.

Another common error is not checking for common formatting differences between phone numbers, such as dashes, spaces, or parenthesis. To troubleshoot this, use the Joi.string().replace() method to remove any non-numeric characters before validation.

It is also important to ensure that the validation rules are not too strict or too loose. If the rules are too strict, valid phone numbers may be rejected. If they are too loose, invalid phone numbers may be accepted. To troubleshoot this, adjust the validation rules accordingly based on the specific requirements and use cases for the phone numbers being validated.

By being aware of these common errors and troubleshooting them effectively, you can ensure that your phone number validation using Joi is accurate and reliable for your website's success.
<h3 id="conclusion">Conclusion</h3>


Validating phone numbers is a crucial aspect of website development and user experience. Joi is a powerful tool that provides an easy and efficient way to validate phone numbers for websites. With Joi's reliable validation features, developers can ensure that phone numbers submitted on their website are correct and accurate.

In this article, we have seen how to validate phone numbers using Joi with practical code examples. We walked through the process of installing Joi and implementing it in our codebase. We also explored the different types of validation rules that Joi provides, such as regex patterns, custom error messages, and more.

Validating phone numbers using Joi can be a game-changer for your website's success. By ensuring that users provide valid phone numbers, you can develop better user experiences, avoid incorrect data, and create a more efficient communication process. With the power of Joi, developers can take their website's validation capabilities to the next level.
I am a driven and diligent DevOps Engineer with demonstrated proficiency in automation and deployment tools, including Jenkins, Docker, Kubernetes, and Ansible. With over 2 years of experience in DevOps and Platform engineering, I specialize in Cloud computing and building infrastructures for Big-Data/Data-Analytics solutions and Cloud Migrations. I am eager to utilize my technical expertise and interpersonal skills in a demanding role and work environment. Additionally, I firmly believe that knowledge is an endless pursuit.

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