What Is Email Validation And How It Works

Over 50 percent of all emails are labeled as spam, regardless of whether they actually are spam or not. That’s bad news for all marketers and the digital businesses whose marketing campaigns they manage. To prevent most of their messages from ending up in the spam folder, marketers need to take care of their mailing lists by performing the so-called email validation on a regular basis.

Have you never heard of email address validation? Don’t worry: you’re not the only one, which is why we decided to explain this useful technique in a language even inexperienced marketers and business owners can easily understand. By the end of this article, you’ll be ready to validate your first list of addresses and reap the numerous benefits associated with this practice.

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What Is Email Validation and Who Uses It?

For digital marketers, collected email addresses are everything. Why? Because email is the channel producing the highest return on investment for marketers, generating $38 for every $1 spent. The problem is that lists of addresses degrade at a rate of around 22 percent each year. In other words, 100,000 valid addresses are guaranteed to become less than 80,000 valid addresses within just one year.

There are many different reasons why marketing lists degrade over time:

The result is always the same: low deliverability and open rates, which, in turn, lead to a worse return on investment from your marketing campaigns. What’s more, they also lower your sender reputation. If you allow it to get too low, your service provider may even kick you from their platform.

That’s why it’s paramount to regularly verify that the addresses you’ve spent so much time collecting are still valid. This can be done manually, but it’s far more efficient to use an email validation online service to perform bulk email validation on hundreds and thousands of addresses at the same time.

Such services are used by most experienced marketers, but they are open to anyone who is using email marketing to sell more products and services, raise awareness of a certain issue, or announce an important update.

How Does Email List Validation Work?

Different email list validation services apply different validation techniques, but the general process can be broken down into the following three steps:

Step 1: Syntax Check

When asked to enter their address, users sometimes make a mistake and don’t notice that the address they’ve entered contains a typo or formatting error. Here are some examples of email addresses that contain obvious mistakes:

The good news is that mail addresses follow a relatively simple set of rules that an email validation test can automatically apply to determine whether an address is valid or not. This step alone is often enough to significantly improve the deliverability of large lists of addresses.

Step 2: Domain Verification

After verifying the syntax of collected addresses, most validation services proceed to check the DNS records associated with the domain name of each address. The domain name is the part of the “@” symbol. If you have an address like example@server.com, then the domain name is server.com.

The goal here is to verify whether the domain name actually exists and accepts emails. Without this step, you would almost certainly lower your sender reputation score by attempting to send messages to non-existing addresses, only to have them bounce back.

While this step is technically complicated, validation services automate it from start to finish, so marketers don’t have to worry about how domain names and mail servers work to improve the performance of their marketing campaigns.

Step 3: Mailbox Validation

The last but certainly not least important step of email validation involves mailbox validation. The goal of this step is to validate that the specific mailbox exists and is able to accept messages. As such, it’s similar to the previous step, but instead of focusing on the part of the email address that goes after the “@” symbol, we’re focusing on the part before it.

One way to perform an email validation check of a mailbox is to send a message to it, but that’s not optimal because you risk hurting your sender reputation score. What’s more, sending a message to each address in your list would be time-consuming and inefficient.

That’s why more sophisticated validation services perform mailbox validation without sending a single message. How? By pinging the SMTP server and analyzing its response code. Again, all this technical stuff happens behind the scenes and usually takes less than a second.

Best Email Validation Practices

For email validation to be as effective as possible, it’s necessary to follow certain best practices, which are based on the shared experience and expertise of countless marketers from around the world and include the following:


Email validation is an essential practice for all marketers who want to see the best return on investment possible on their marketing campaigns. While it’s certainly true that there’s a lot that goes into thoroughly validating an address, marketers don’t have to worry about the technical aspect of this process because they can use an online validation service and let it do all the difficult work for them.

What Is Email Validation - FAQs

1. What is email validation?

Email validation is the process of verifying whether an email address is legitimate or not. It can be performed manually, but most marketers use a bulk validation checker to quickly verify hundreds and thousands of addresses at once.

2. What are the validation rules for email addresses?

When performing a syntax validation of an email address, it’s important to check that the recipient name is up to 64 characters long and contains only allowed characters. A valid email address must then include the “@” symbol, followed by a domain name.

3. What are the benefits of email list validation?

The main benefit of list validation is that it helps increase email deliverability, a number that indicates how many messages have been successfully delivered. This, in turn, improves the ROI of marketing campaigns.

4. How can I protect my list with email validation?

To protect your list with email validation, you need to choose a reputable validation service capable of quickly recognizing and flagging all invalid addresses. You then need to use this service on a regular basis because lists of addresses degrade at a rate of around 22 percent per year.

5. What types of emails does email validation check remove?

A comprehensive validation check can remove all invalid email addresses, including addresses with spelling mistakes, syntax errors, as well as addresses that are no longer active.

Clean Email Team Updated on May 8, 2022