Email Validation: How to Keep Your Email List Clean and Safe

Mike Arsenault
July 20, 2021
minute read

Your email list is one of your most valuable business resources. You depend on your list for email marketing, customer outreach, and transactional emails. Your email list is even valuable for other marketing channels, like social media and paid advertising.

But, email addresses are extremely easy to falsify. And, people often give fake email addresses to avoid email marketing. Moreover, sending emails to spam traps and bots hurts your sender reputation even more than sending to an incorrect or misspelled email address.

Additionally, having unusable emails on your list negatively impacts almost every email marketing metric and decreases the efficiency of your email marketing.

So, what can you do?

Implement email validation into your email program. It’s also called email verification, and adding email validation to your email system immediately reduces your bounce rates and protects your sender reputation.

To demonstrate the importance of this issue, we took a random sample of 1,163,174 email addresses that were validated by Rejoiner clients over the last 60 days.

12% of them were too risky to send to. Imagine that. 12% of your net new email subscribers may, in fact, be damaging your sending reputation.

The good news is that there is an effective way to eliminate this problem.

Email validation tools are extremely easy to setup and use. So, it won’t take long to cover all the bases and show you how to use email verification to protect your email lists and improve your email program.

What is Email Validation?

As you know, email addresses can be extremely transient. They’re very easy to create, and many people dislike a crowded inbox. So, there’s a lot of temptation to use a fake email address or a disposable email address. The demand for disposable email addresses is so high that there are tools to automate dummy email creation.

Then there are bots and spam traps. People misspell email addresses. Many email inboxes aren’t monitored. The land of email marketing is a minefield of invalid email addresses.

Email validation is an automated process that verifies newly acquired email addresses in real time, before your email program sends them any emails, marketing or otherwise. If an email address is verified, you know it’s not a bot, spam trap, known complainer, or anything else that might hurt your sender reputation and reduce email deliverability.

Email validation benefits

Email verification ensures that only usable emails are added to your email list. That way you know that every email you have is attached to a real inbox.

This reduces your bounce rate, and simultaneously helps you maintain a healthy sender reputation. A quality email validation tool imposes filters for almost every type of bad email address. Email verification removes:

  • Disposable emails.

    This filter removes dummy and temporary email addresses.
  • Invalid emails.

    This removes any email address with an invalid format or that doesn’t link to an active inbox.
  • Misspelled emails.

    Catches invalid emails that were unintentionally submitted.
  • Spam trap emails.

    These are addresses that are specifically designed to catch spammers, since spammers rarely validate email addresses before sending blasts, and usually send emails without getting permission first.
  • Catch-all emails.

    This weeds out emails that start with “sales,” “support,” “admin,” and similar prefixes, so you don’t send emails to unmonitored inboxes.
  • Emails from new domains.

    Prevents fraud by eliminating emails that are hosted on brand new domains.
Email validation issues

Using these filters to clean your email lists reduces both your soft and hard bounces, and minimize complaints and unsubscribes. That way, fewer of your emails are wasted, and you won’t get blacklisted or marked as a spammer.

Email Deliverability: The Ultimate Guide to Keep Your Emails Out of the Spam Folder
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How to Validate Email Addresses

As we mentioned earlier, email verification is best accomplished with validation tools. There are two major categories of email validation tools:

  • APIs. An API enables you to link your email program directly to an email verification database.
  • Manual validation tools. These give you access to an email validation database through a self-service portal for uploading email lists.

Both tools validate email addresses in real time. However, manual email verification tools are not entirely automated.

Manual validation tools require you to export your email list to a .csv, .txt, or Excel file and upload it to their email processor. This is known as “email list cleaning.” Depending on the size of your list, it usually takes a few minutes to the validate email addresses and return your results. If you have a lot of emails to check, it will take longer.

Email verification services verify emails using the same method, regardless of whether you manually upload your lists or connect via their API.

How Does Email Validation Work?

Most email validation providers validate emails using a three-step process.

Email Validation Process

Step 1: Syntax and Formatting

The first thing your email validation service checks is the format of an email address. This simply ensures that the email has all the right information in the right places. It checks for things like missing @ symbols, invalid characters, and out of place domain names.

This check eliminates entries that are just not actual email addresses due to intentional falsification or misspelling. If you have it configured to do so, this stage is also where unmonitored inboxes like admin and sales emails get filtered out.

Step 2: Domain Verification

Next, the email validator will check to make sure that the domain is valid and active. This is a matter of looking at the DNS and MX records to ensure that the domain is properly setup and activated, and that the mailbox can receive messages.

This is where the correctly formatted, but invalid, emails are removed from your list.

Step 3: Mailbox Check

This last stage is where the rest of the bad emails get caught.

Your email validator will contact the mail server through SMTP and find out if the mailbox really exists. This filters out most disposable email addresses.

None of these three checks require your email validator to send an email. It takes a second or two to check an email address.

There are two ways to run emails through this validation process: data integration and list cleaning.

Implementing Email Validation

Using an API—often called “data integration”—enables you to automate the email validation process. Whenever an email is added to your list, your email system will automatically send it out for verification before sending any emails to that address.

Additionally, an email validation API can help deter people from entering disposable or false emails in the first place. You can use the API for inline email validation on your email collection forms. That way, if someone enters an invalid email address, it will prompt them to correct it before they can proceed.

This helps keep unusable email addresses out of your database in the first place, rather than collecting and then removing them. It can also help reduce fraud, since most fraudsters prefer not to commit fraud using a valid email address.

If you need an external email validation service, check out these providers:

Most email checkers offer a bit of free email validation, so you can test drive their service. However, at some point you’ll need to pay.

All of these providers offer APIs, and a few have manual upload processing services. Both methods are simple to setup and use. Using an API may seem scary. But, most email validators use a simple, unique web URL to connect to their system. It takes a matter of minutes to complete the integration.

On the other hand, you can have your email service provider take care of the email validation for you. That way, the email validation process is integrated into your email provider’s software, and all you have to do is add email addresses and send emails.

Your email service provider will automatically verify email addresses in real time, before any emails are sent to newly collected emails. The process is entirely transparent to you.

For example, email address validation is baked into every Rejoiner subscription. Our platform is already connected to an email validation service, and we conduct real-time email verification on every email address before emails go out.

You’ll see the verification status on all customer profiles. So, you know which emails are bad. We don’t just toss them. Sometimes, you may want to send to certain email addresses—like a customer support email address—even though the validation system flagged the address.

These are the nuts and bolts of email validating email addresses. Even if you do it yourself, adding email validation to your email system will greatly improve your email marketing program and help you get more return from every email you send.

What to Do Next

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Mike Arsenault

Founder & CEO

For the last 10 years, Mike has worked with brands like Moosejaw, Hydroflask, Peak Design, Triumph, Hearst & Guthy Renker to provide the strategy & technology with which they use email to drive revenue growth. He's also the Founder of Rejoiner, a SaaS marketing platform built for ecommerce businesses.

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