How email verification can optimize your transactional email sending

There are a few reasons why your database might contain invalid email addresses. Sometimes, they are old and become inactive; sometimes, people use disposable domains, enter a fake email, or simply type it incorrectly. Sometimes, the reason can be more nefarious, such as in the case of bot activity. It’s more or less impossible to avoid invalid emails completely, and that’s why you need to take steps to clean your lists.

In this article, we’ll explain why email verification is crucial for any business sending emails and give you tips on how to maintain good email list hygiene.

What is email verification?

Email verification is the process of checking email address validity. This involves verifying that an email address is properly formatted, actually exists, and belongs to an active and deliverable mailbox.

Email verification is slightly different from email validation as it can also identify specific types of email addresses, such as those that are role-based or belong to a catch-all domain. Email validation, on the other hand, simply validates that the email address format and characters used follow the necessary standards.

By verifying emails, you can exclude invalid email addresses from your sendings to reduce bounce rates and improve deliverability.

How does email verification work?

The email verification process involves performing multiple types of checks to validate the email address. 

1. A syntax check verifies that the email address is properly formatted and includes a prefix or username, the @ symbol, a domain, and a top-level domain (TLD).

2. A domain verification check via DNS (Domain Name System) lookup to verify that the domain exists and has valid MX (Mail Exchange) records.

3. An SMTP check connects to the mail server to see if the email address exists, accepts mail, and whether the domain is configured to accept all emails, even if the email address doesn’t exist. 

4. A disposable email check checks the domain against known disposable or temporary email domains.

Who needs email verification?

Anyone sending emails to customers, users or subscribers needs email verification. An unverified email list can harm your sending reputation and deliverability rates if it contains invalid emails. 

The longer you leave your recipients’ emails unchecked, the more likely it is that some of them will become inactive—you might even end up with a few spam traps. The larger the number of bad email addresses you send to, the more impact it will have on your sender reputation. As a result mailbox providers will be less likely to deliver your emails to the inbox, instead sending them to the spam folder or rejecting them completely. You could also land your IP address or domain on an email blocklist. 

This means that your customers or users might not receive important emails.

How you can benefit from email verification

Email verification is a crucial step in maintaining healthy sending practices for your transactional email. With a clean and up-to-date list, you will improve deliverability, enhance the customer experience, and optimize email sending for better cost efficiency and use of resources. 

Correct customer information 

Your customers expect to hear from you, whether that’s with important updates, account activity, or order confirmations. Equally, there may be times when you need to communicate something urgent to them. Having the correct customer information is essential for transactional messaging, and email verification can help you combat instances of human error when incorrect information is provided.

Increased conversions 

When people enter a valid email address, you get the opportunity to convert them into customers. For example, an app could send people emails with help setting up their account, or an e-commerce store could send abandoned cart messages.

Lower bounce rates 

Email checkers help to identify email addresses that are likely to hard bounce. By removing these from your email list or excluding them from your sendings, you’ll deliver a higher percentage of emails and improve your deliverability.

Reduced sending costs 

Most transactional ESPs (Email Service Providers) charge based on email sending volume. By only sending messages to real, valid recipients, you could potentially lower the amount you spend each month on sending transactional emails. What’s more, you’ll preserve your sending resources, such as daily API requests, making it easier to stay within limits.

More accurate results 

If you eliminate fake or invalid email addresses, your analytics will reflect more accurate results, enabling you to make better-informed decisions about your sending strategy. What’s more, your engagement metrics, such as click rate, open rate, and conversion rate will increase.

How to verify email addresses

There are manual methods of verifying email addresses, but they involve carrying out the multiple types of checks individually, some of which are generally quite a cumbersome process. Here are 4 ways to verify emails, starting with the easiest and most accurate:

1. Use an email verification service

Whether you have 1 email address or 1 million, an email verification service allows you to submit a whole list of emails to verify them in bulk. This usually involves uploading the list as a CSV file so the email verifier can get to work validating each email address. It will then return the results with a breakdown of the types of emails that appear on your list and allow you to download the results as a CSV file, so you can remove or exclude invalid emails. 

These services usually also have an email address checker that lets you submit a single email address at a time. This is useful if you only need to verify one or a few emails.

MailerSend has an inbuilt email verification tool that you can access in-app to upload and verify your email lists. You can also verify email lists or a single email address with the API using the email_verification endpoint.

2. Use real-time email verification

Real-time email verification involves using an API integration to check email addresses as they are submitted to your app or website during the sign-up process or anywhere else you want to validate emails. 

It works like this:

1. A user submits their email through a signup form (or other collection point), which is configured to send the email to the backend for verification.

2. The backend receives the email address and sends it via the API to the email verification service you are using to be verified, which returns the results.

3. You can then configure your signup form to provide a response to the user based on the results, for example, if the email is invalid: “Please enter a valid email address”. You can also use the results to update your database or share the data across apps like your CRM or other marketing tools.  

Real-time email verification is useful because it prevents invalid emails from entering your database in the first place. It also improves the user experience by letting people know when they’ve entered an incorrect email address, giving them the chance to correct it. Combining real-time verification with regular bulk email verification is a solid approach to maintaining a healthy, clean recipient list. 

3. Ping an email address

Email pinging (or SMTP authentication) relies on SMTP to connect to the email server and check for email address validity. This involves using Telnet and command prompts to simulate sending an email and seeing how the server responds. 

Pinging an email can be useful for verifying that a mail server exists but it’s not 100% reliable. The results lack context, for example, a catch-all email address will be verified as valid even if it doesn’t belong to a real email account, and other types of emails won’t be given any kind of categorization. Plus, you can be met with other limitations, such as your request being blocked.

4. Use email validation methods

Although often used interchangeably, email validation is not the same as email verification. Email validation validates that an email address follows email standards in regard to syntax and allowed characters. But, it can still be a useful way to filter out some invalid emails. 

There are functions, such as PHP’s FILTER_VALIDATE_EMAIL and FILTER_SANITIZE_EMAIL that allow you to detect whether an email address follows these standards and then sanitize them by removing invalid characters if necessary. It’s also possible to validate emails using regex (regular expressions) to customize the specifications for a valid email. 

Again, these methods can be useful but they won’t be able to tell you if an email address is real and belongs to a deliverable mailbox.

Understanding email verification results

Different email verification tools provide different results, with some identifying more types of emails than others. Below is an overview of email types and whether or not they are okay to send to, risky to send to, or shouldn’t be sent to at all. 

These statuses and categorizations are based on MailerSend’s email verification tool, so keep in mind that other tools' results may differ.

Valid 🥳

Email addresses with this status are safe to send to—awesome!

Risky ⚠️

You should only send to these email addresses with caution as they may be undeliverable or be attached to an inbox that isn’t checked frequently or at all. 

• Catch_all: The recipient’s mail server can accept incoming messages, however, it’s not guaranteed that the email address belongs to a real person

• Mailbox_full: The recipient’s inbox is full and may not be able to accept new incoming emails

• Role_based: The email address is role-based (for example, admin@example.com) and therefore may not belong to an individual 

• Unknown: We are unable to determine if the email is valid

Do not send 🙅

These are the email addresses that you should add to your suppressions list (blocklist) and cease sending to.

• Syntax_error: The email address is not valid

• Typo: The email address has a typo. You may be able to correct the email address and retest if the typo is obvious, for example, amy@gmial.com (gmail)

• Mailbox_not_found: The inbox does not exist

• Disposable: A disposable email address is a temporary email address used by bots or people who want to hide their real email address

• Mailbox_blocked: The recipient’s mailbox is blocked by its service provider due to poor sending practices

Email verification best practices and tips

Verifying emails and maintaining a healthy database is not a “maybe I’ll do it when I have time” kind of project. The sooner you make email verification a standard part of your process, the better. Trust me, you will be thankful that you did. So here are a few tips and best practices for keeping your email lists clean.

1. Use a combination of methods 

Verifying emails at the point of capture and performing regular bulk email verification will allow you to minimize the number of invalid emails that reach your list and remove any old email addresses that are no longer active or might have become spam traps. Real-time verification is also an effective way to improve the user experience during signup by providing feedback for the user to act on.

2. Stick to a list cleaning schedule

Be sure to clean your email list at least once every 6 months so you can remove any that have become inactive in that time. Even better if you can clean your list more frequently. 

3. Monitor email bounce rates

High bounce rates can indicate various deliverability issues, including the presence of invalid email addresses on your list. Monitoring bounce rates will alert you to an issue as soon as it happens so you can check your database for invalid emails and remove them before they damage your sender reputation.

4. Send an account verification email

In addition to using an email verification service, send new account signups a verification email (or double opt-in email) for them to confirm their email address. Keep in mind that some bot signups can and do programmatically confirm via these emails, so it should be used in combination with other verification methods.

Email verification is key to good transactional email deliverability

Verifying your recipients’ email addresses is the best way to keep your transactional sendings performing at their best. You’ll be able to keep customer and user information up to date, improve your sender reputation and deliverability, and continue to build strong relationships with recipients. You might even save a buck or two as well!

Try out MailerSend’s email verification tool from within the app, let us know what you think and tell us about your experience with email list cleaning in the comments.