How to Verify and Clean Email Lists

Clean email lists

As an email marketer, you must have come across situations when your email campaign is ready, and you upload your email list, but as soon as you press the send button, your emails start bouncing. So, what now? Well, email list verification and email validation and help you to avoid such issues. So, let's understand how to verify emails and clean email lists in detail.

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What is Email Verification?

Email Marketing is not just about crafting a perfect subject line, email copy, placing the CTA right, or including powerful images. There's a lot of background work that's involved. One such work is verifying and cleaning the email list.

Email verification is the way to ensure that your lists of emails are valid and connected to an inbox. It helps in increasing the deliverability of your email lists further, allowing you to reach your customers. Email verification is an integral part of best practices in email marketing.

Email verifier is essential to build a healthy email list. To reap more out of an email verified, let's find out how an email verifier works.

How does an email verifier work?

The email verifying process involves eliminating invalid email addresses by analyzing your email list. The main features consist of syntax and formatting tests, server confirmation, and mailbox validation. The following is the general method for how email verification functions:

1. Syntax check

It checks whether the email address is spelled in the right way. The email address shouldn't have any commas and spaces, and all the periods, '@' symbols, the domain name should be in a proper structure.

The following are the checklist for syntax control algorithms:

  • It checks the local-part, the at-symbol ( @ ), and a domain name

with a dot-symbol ( . ) are present, it doesn't allow more than

64 characters in the local-part, proper placement of dots (.) and

the symbols (@), special characters (? “ # $ % & ` * + _- . / | ^ {}) can only be used in the local part of an email address, but not in the beginning or at the end of the local-part.

  • It checks common mistakes like periods (.) at the start or the end of the email address, commas (,) instead of periods (.), semi-colon (; ) or apostrophe (') instead of the at-sign (@).

  • Further, verification is done for the spaces or blank areas ( ) in the middle or at the end of the address, double periods (..) in the local part or domain name, missing ".com" or period ( . ) in the address, or any misplaced signs (@).

  • Email verifiers detect any possible spam traps and invalid email addresses before they're flagged by ISPs (Internet service providers) or ESPs (Email Service provider).

2. Domain existence check

Email verification services check if the domain name is written correctly and the web and domain are real and operational. For example, if someone entered the email address: and the domain under is not registered, an email verifier would mark it as invalid.

3. MX record check

A Mail exchanger record or MX records identify whether the email address is valid. Unlike the email verifier, which checks the format and characters of an email address, this checks if the domain name is present and has email DNS settings configured.

4. Catch-all domain check

A catch-all server accepts all emails sent to the domain, regardless of whether the particular mailbox exists. Here, the email verifier checks if the email is part of an entire domain.

The domain name is verified automatically for a catch-all by a credible bulk email verifier. You will act at your own risk if you see a verified email as a catch-all email and choose whether you want to send emails to it or delete it from the list entirely.

5. SMTP authentication (Email address ping)

Individual mailbox validation is the final step in the process.

Email verification services use the SMTP protocol to check if the recipient's domain has a valid MX record. If it does, then it checks if the username exists or not and proceeds.

Now you know how an email verifier works, but why is it essential to verify emails?

Why is email verification so important?

Verifying your email address is essential as it makes your email marketing more effective.

This impacts your deliverability rate as the hard bounce rate might exceed the allowable rate if you don't test email lists frequently, and the credibility of the sender will get a real hit.

Maintain your email list free of typos, invalid, and provisional email accounts that can impact your deliverability. The last thing you might wish is to avoid getting into the spam folder or refusing your emails because of insufficient data quality.

Types of Email verifiers

There are many email verification services out there but what type of service you choose should be based on your needs and business type. Let's look at two main types of email verification services

Software email verifiers

Verifying services and tools provide a reasonable solution for bigger businesses where one person is responsible for lead list management and verification.

The benefits of software email verifiers are as follows:

  • Automated verification

  • Unlimited email searches validation

  • Full database ownership

However, software email verifiers have quite a few inconveniences:

  • Installation updates.

  • Back-ups (not automatic cloud storage).

  • Access to one device.

  • PC and OS requirements are restricted.

  • No integrations.

SaaS email verifiers

SaaS email verifiers provide a cloud-based framework that allows you to use the browser to access all data stored in the cloud directly. Check Mailmodo, a saas tool for all your email marketing needs, offering a subscription-based model.

Some of the many advantages include:

  • Unrestricted access from every part of the world to your account and database.

  • Team choice.

  • No limitation in OS.

  • APIs.

  • A toolbox is also included with one subscription.

Since we discussed the types of email verifiers, let's find out what you should look for in a good email verification service.

How to choose the best email verification service?

There are various email verifiers out there that are equally consistent with their algorithms, servers, programming, and optional service. Below are some tips to help you figure out the best email verification service.


Before trusting any service with your most precious assets:

  1. Don't risk losing, stolen, or selling your data.

  2. See their website for information on their physical address, telephone, and email help.

  3. Contact them to ask some questions to ensure that they are legitimate.


Seek to find the perfect service at the best price from the website. Remember, the cheapest choice is not always the best choice.

Verification method

Not everybody on websites shares how the verification process is carried out. However, you would like to do your research to make sure the reports are correct. Check the verification method of the Mailmodo.

Extra services

Check if there are any extra features and benefits that they provide. There's no point in switching between a dozen players if you can all get them on a single platform.

API Verification

You will need an API to implement email verification on your platform or product directly. It is not a must-have for any email verification platform, but it opens up many email verification possibilities.


A vital component of any excellent email verification service helps ensure that your chosen service has at least two ways to reach the team (preferably person, 24 hours a day) if you have questions or problems.

You can also check out our exclusive article on email verification and validation tools for 2021: Best Email Verification and Validation Tools of 2021


Once you have verified your email list, you can see that it improves your deliverability numbers and also helps you to maintain your sender reputation. In case you would like to know more about this, feel free to contact the Mailmodo team and we would love to tell you more about email hygiene and how you can improve your deliverability and conversions.

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