How to Verify Email Lists

It takes time, effort, and money to build a strong email list, so it’s essential to take good care of it, which is where email list verification comes in. Marketers, salespeople, and businesses that verify email lists on a regular basis achieve high deliverability, allowing them to get higher ROIs on marketing spend.

Why Is It Important to Verify Email Lists?

If you want an effective mailing list, strive for a bounce rate of less than 2%. With a list of newly collected addresses, achieving this target isn't difficult. The problem is that email address lists don’t stay fresh for long.

It’s estimated that mailing lists degrade at a rate of 22.5% per year, which largely explains why the average bounce rate is only 7.75%, according to a report by Constant Contact. Here are some reasons why email lists turn sour quickly:

Regardless of the reasons behind mailing list decay, the consequences are the same. First, your bounce rate increases. This prompts internet service providers (ISPs) to lower your sender’s reputation. Finally, your messages are flagged as spam and moved to the spam folder. In the worst-case scenario, your account may be suspended for spending unsolicited or spammy messages.

The good news is that you can improve the email deliverability of your mailing list when you verify email list addresses and get rid of inactive and unresponsive ones. The result of a successful list verification is an instant improvement in campaign performance. That’s why email verification should be performed on a regular basis and whenever a new mailing list is created or an existing one updated.

How to Verify Email Lists?

Learning how to verify email address lists is as easy as learning the art of collecting them when you break down the process into individual steps:

1. Perform an Email Syntax Check

All mail addresses share the same format: username, followed by the @ symbol, followed by the domain. The username can be up to 64 characters long and contain the following special characters: ! # $ % & ‘ * + — / = ? ^ _ ` . { | } ~

That’s why the following addresses are valid:

But these addresses are not:

To start, perform a simple email validation check to verify email address list for syntax errors, which are usually the result of errors made by the user. Sophisticated email address syntax checks may attempt to fix recognizable syntax errors, such as or user@outlook.comm.

2. Get Rid of Throwaway and Catch-All Emails

Throwaway addresses have limited value when it comes to email marketing. The same can be said about catch-all emails, which receive messages sent to an incorrect address.

Other types of valid but undesirable addresses include spam detection traps and role-based mail accounts such as admin@ or info@. Sending messages to such addresses can get your address put on a block list.

3. Check the Domain Name

Next is the verification of DNS entries corresponding to domain names. The goal is to determine if the domain name has a valid MX record. The MX record specifies the mail server responsible for accepting messages on behalf of a domain name. If the domain name doesn’t have a valid MX record, it’s marked accordingly and discarded from the address list.

One popular DNS checker is MXToolbox. Here’s some of the information it displays when the domain name “” is entered: DNS Record found

And here’s what it displays when the domain name “gmail.comm” is entered: Sorry, we couldn't find any name servers for 'gmail.comm'

4. Ping the Mail Server

The goal of this email verification method is to elicit a response from a mail server to confirm that an email address is valid. It can be performed manually using telnet, an application protocol that provides a bidirectional interactive text-oriented communication facility using a terminal, but automating it saves time.

Here’s an example of a telnet verification of a Gmail mail server:

220 ESMTP u8si73423454wsd.18 - gsmtp
250 at your service
250 2.1.0 OK u8si73423454wsd.18 - gsmtp
550-5.1.1 The email account that you tried to reach does not exist. Please try
550-5.1.1 double-checking the recipient's email address for typos or
550-5.1.1 unnecessary spaces. Learn more at
550 5.1.1 u8si7354684wi
v.18 - gsmtp
221 2.0.0 closing connection u8si73423454wsd.18 - gsmtp

If the address is invalid, you see something like “the account that you tried to reach does not exist” and the response code 550. On the other hand, valid addresses are marked by the response code 250.

5. Keep Up with List Changes

Remember, people change their email addresses for all sorts of reasons. A job change often means a new work email, while personal milestones like marriage can lead to a name, and subsequently, email change. Plus, with so many email services out there, people often switch to get better features.

Regular email list verification keeps you up to speed with these changes. It's not just about dodging email bounces; it's about ensuring your messages reach those who are truly interested. It's similar to keeping your phone contacts updated – staying in touch with the right crowd is key. This way, you're not only saving resources but also keeping your audience engaged with content that finds them where they're active.

Use an Email Verification Tool

Manual verification takes time and effort. To help you save time, check out some of these email list verify tools that perform all the above-described verification procedures with a simple click. Some even let you verify emails online free of charge, giving you a chance to see how a free email verification service works without spending any money.

To verify email for free with one of the best email verification services, you simply upload your list of addresses and let the tool do its job. It shouldn’t take much time for the tool to mark invalid emails accordingly, leaving you with a clean list that is guaranteed to improve your deliverability.

The best email list cleaning service is the one that provides all the services you need and at a price that fits your budget. There are many bulk email verification services to choose from, and each service has its pros and cons.

1. ZeroBounce

ZeroBounce has rightfully earned thousands of positive reviews from individual and enterprise customers, who praise it for its accuracy, security, and a full range of features.

All ZeroBounce users get 100 free monthly verifications, and more verifications can be purchased either monthly or using a pay-as-you-go model. The more verifications you purchase at once, the less you’ll pay to verify each email. For example, 2,000 verifications cost $0.0075 per verification, but 10,000 verifications cost just $0.0064 per verification. Enterprise customers interested in purchasing more than 2,000,000 verifications receive additional discounts.

ZeroBounce best email verifier tool

ZeroBounce integrates with the leading email marketing platforms and services, including Drip, MailChimp, HubSpot, Shopify, and others. Its email validation API is documented very well and is easy to integrate. For these and other reasons, we recommend this email verification tool to everyone who wants to validate email addresses to improve email deliverability.

Wondering how ZeroBounce works? Check to see if an email is valid right here with our email validating tool. Simply enter an email address to see the speed and accuracy of the ZeroBounce validation system.

2. Clearout

Clearout is an email finder and verification service that also earns high ratings from its customers. It receives positive reviews for its blazing fast speed, amazing support, easy-to-use platform, and 98% accuracy.

You can start with a free account that includes 100 free credits. You'll need one credit to verify each email address. After using your free credits, you can pay as you go or sign up for a monthly or annual subscription. And, the more credit you buy each month, the less you'll pay for each credit. With Clearout, 2000 credits cost $.007 per credit, and 10,000 credits cost $.0058 per credit if you're on the pay-as-you-go plan.

Clearout email list verification software

Clearout uses more than 20 refined validation checks, including syntax validation, catch-all validation, removing duplicates, and spam trap detection. It can also check bulk lists that include a million emails. Your data is secure with Clearout's military-grade confidentiality and GDPR compliance.

In addition to its Email Verify tool, Clearout has a tool that will find mail addresses based on a person's name, company, or domain. Another tool validates phone numbers.

3. DeBounce

DeBounce is a bulk email validation tool that's simple and intuitive to use. All you do is upload your list as a TXT or CSV file and wait for your file to process. DeBounce identifies syntax, spam traps, bounce, catch-all, and disposable emails. It then provides you with a clean list you can download. On the downside, DeBounce's accuracy rate may not be as high as other email verification services, and it performs fewer validation checks than other services.

DeBounce email list verify software

DeBounce lets you try the service without asking for your credit card. There's no monthly payment, no subscriptions, and no upfront fees. Plus, when you sign up, you get 100 free credits, and your credits never expire. DeBounce also uses a sliding price scale, so the more credits you buy, the less you'll pay for each credit. So, 2000 verifications cost $.0032 each, and the price goes down to $.0015 per verification when you purchase 10,000 credits.

4. EmailChecker

If you're looking for an email checking service that's been around for a while, look to Email Checker. Email Checker has been validating mail addresses since 2009. It grew from a simple and free email verification tool that checked the validity of emails to a feature-rich email verification service. Email Checker claims to have the most advanced email verification platform on the web. It performs syntax and format checking, domain checking, and mailbox checking.

EmailChecker software to verify email lists

Email Checker may have the most flexible payment options. You can purchase credits in pre-paid blocks, which start at $14 for 1000 credits. With this plan, you pay as you go and pay only for what you need. If you have an ongoing need, check into a monthly subscription plan, starting at $10 per month for 1000 verifications each month. With a subscription plan, file uploads are limited to 500,000 records, and you must subscribe for at least two months.

5. Hunter

If you like supporting the underdog, check out Hunter. Hunter is a small company that provides services for millions of customers. And it's the perfect tool if you have a small mailing list and add less than 50 new emails to your list each month. If this sounds like you and your marketing budget could use some help, Hunter has a Free plan that gives you 50 verifications per month. If you have a larger list, the Starter plan at $49 per month gives you 1000 verifications per month.

Hunter email verifier for email lists

Hunter also has search tools. The Free plan comes with 25 searches per month, and the Starter plan includes 500 searches. These searches include a domain search that lists the names and email addresses associated with a company's domain name, an email finder that gives you the contact information of people you want to target, and an author finder that locates the mail address of the author of a blog or web article.

Check out our full list of the best email verification services and tools.


Bulk email verification is an essential procedure that should be performed regularly to maintain the health of mailing lists. With the right tool, it can take less than a minute and cost nothing at all. When you know how to verify emails, you can discard all invalid addresses. Then, with a current and accurate mailing list, you can expect your bounce rate to decrease, your sender reputation to improve, and the ROI of your email marketing campaigns to skyrocket.

How to Verify Email Address - FAQs

1. Why do we verify email?

When consumers enter their email address in your newsletter sign-up form, some people may not give you the correct information or may type the wrong information by accident. Email addresses need to be verified so that you don't send messages to addresses that no longer exist or are invalid. Sending to verified mail addresses eliminates hard bounces, reduces spam complaints, and keeps your messages from being placed on a block list.

2. How can I verify an email address?

There are several ways to verify email addresses. If you only have a few addresses to check, verify each one individually through an online email checker. If you check a large number of email addresses each month or have a large batch to verify, use an email verification tool to automate the process.

3. Can I verify email list online for free?

Yes, it’s possible to verify an email list online free of charge using one of many available email verifiers. Many services provide a small number of verifications for free so that you can evaluate their services. You might also find services that offer a free account with limited features and a small number of verifications each month.

4. How frequently should I verify email lists?

It depends on how large your list is, how often you send a campaign, and your bounce rate. It’s a good idea to verify email lists of addresses regularly and at least every six months. The smaller the list and the lower the bounce rate, the less often you can clean your list. If your organization adds hundreds of addresses each month, monthly cleaning might be a better idea.