How to Verify an Email Address: A Comprehensive Guide

Knowing how to verify email addresses is one of the easiest ways to improve email deliverabilityⓘ and keep your sender reputation healthy. While there are several ways to check whether an email address is valid, not all methods provide the same level of accuracy. In this guide, ZeroBounce's email deliverabilityⓘ experts explain what email verification is and why it’s important, the most common email verification methods, how they work, and when to use each one.

This guide covers everything you need to know about how to verify email addresses.

What Is email verification?

Email verification is a process that checks whether an email address is valid and configured to receive incoming messages.

Email verification and validation are sometimes used interchangeably, though they are different processes that complement each other. Email validation is a process for checking that the email address uses the correct syntax. A valid email address must always follow this format:

Username @ Domain Name .com (or some other TLD, e.g., .net, .edu, .gov)

While validation checks the syntax, verification is a more technical process which involves various checks, including:

• Checking DNS records for valid MX or A-type
• Performing a real-time SMTP checkⓘ
• Looking for spam trap signatures and disposable domains
• Cross-referencing with global suppression lists

An email address must successfully pass all of these verification checks to be considered verified and valid for use.

Why email verification is important

Email verification is critical for anyone who participates in email outreach, including email marketers, sales and business development, recruiters, and more. Here’s why:

• Reduces email bounce rates – The primary reason for a bounced email is an invalid email address. You can easily avoid a bounce if you verify an email address first.
• Keeps your email list up-to-date – Our study of over ten billion email addresses indicates that email lists decay by 28% annually. Verifying email addresses at least quarterly can detect and eliminate fake, outdated, or abandoned emails.
• Enhances email deliverability – To reach inboxes, you need a list of valid email addresses. Verifying emails first ensures that your bounce rate stays low and helps you avoid other deliverability issues, including spam complaints.
• Protects your sender reputation – ISPs give every mass sender a sender score. By verifying your emails, you avoid high bounce rates, spam complaints, and other risk factors that can hurt your sender reputation.

Methods to verify an email address

1. Send a test email

The most direct method to verify an email address is to send an email. To do this, create an email as normal and attempt the delivery. If the email address is invalid, your message will return with a bounceback message.

If the email address you’re trying to contact is invalid, it will bounce back to you.

If you receive a bounce notification, delete the address from your email list.

However, there are a few significant issues with this method:

• High bounce rates – If the email address is invalid, your message will bounce. While the occasional bounce isn’t a risk, mass senders will need to verify hundreds or thousands of addresses, resulting in dangerously high bounce rates.
• It doesn’t provide enough information – The email address you’re attempting to verify may have other risks. For example, an abuse email is valid, but it belongs to an account associated with frequent spam complaints. You’ll want to avoid problematic emails, like abuse or catch-alls, which lead to high spam complaint rates or poor engagement.
• Sender reputation damage – If your email bounce and spam complaint rates climb, ISPs will lower your sender score. This result will lower your email deliverability, making your outreach ineffective even after you identify the valid emails on your list.

2. Search the email address on Google

It’s possible to locate the email address via Google if it’s listed on a website, social media profile, or some other public listing. Enter the email address into the search bar, and check the returned results.

However, even if your search returns a result, the address you find is not guaranteed to be current. Using this method requires you to send a test email, which poses the risks described above.

3. Ping the email server

Email pinging sends a message to the mail server you’re trying to verify without sending an actual email. If the attempt to reach the server is successful, the address may be valid.

You can ping an email server using TELNET commands. You may need to enable this first on your PC:

1. From Start, find your ‘Turn Windows features on or off Settings.’
2. Look for ‘Telnet Client’ and check the box. Click OK.
   
   
   
   

   Select Telnet Client from the menu.

3. Open up the Command Prompt.
4. Enter ‘nslookup -type=mx domain.com’. Substitute the example with the domain that’s associated with the email address you’re trying to reach.
   
   
5. The result shows that there are mail servers configured with the proper mail exchange records. You can now use the domain to enter the following command: ‘telnet domain.com 25’.
6. If you’re successful in connecting to the domain, enter the following command: ‘HELO anydomain.com’.
7. Next, enter this command: ‘MAIL FROM:< your_email_address_here >’.
8. Finally, enter this command: ‘RCPT TO:< the_email_you_want_to_verify >’.

Based on the results, you can determine if the address is valid or unknown by the mail server.

However, manual pinging has several significant drawbacks:

• It’s not always accurate – Many servers will automatically block pings. On the other hand, some servers will return an OK result for any email regardless of validity.
• It’s time-consuming – Using this process for one address is fine. However, if you’re a business with hundreds of email addresses, you can’t realistically ping all of them.
• It doesn’t provide any data – A ping will only tell you if the address is known. It doesn’t tell you its function, whether it’s meant to receive incoming mail or any other critical information for a sender to know.

4. Use an email verification tool (recommended)

An email verification tool provides the most accurate results and eliminates any drawbacks related to the labor or infrastructure required.

Here’s how an email verification tool works.

1. Go to a tool like ZeroBounce's free email verifier. Then, enter the email address you want to verify or upload your entire list.
2. Get your results. If you validate a single email address, the result will be instant. However, larger lists will take additional time to verify accurately.
   
   

This email verification tool rapidly performs a series of checks, including:

• Syntax and typo checks
• SMTP checks
• DNS record checks
• Checks for spam trap signatures
• Disposable domain checks
• Abuse report history

If the address passes all of these checks, it’s considered valid. If any additional data is found, it’s provided in the sub-status field (e.g., do_not_mail, role-based catch-all). The sub-status field will also provide other helpful data, such as the domain name, SMTP provider, and MX record.

An email verification tool can accurately check any number of email addresses using its dedicated infrastructure and verification process.

How does an email verifier work?

The safest method for reliably verifying an email address is to use a dedicated email verifier.

Here’s how the ZeroBounce email verification tool works and delivers accurate results.

• Syntax/typo check – First, the address undergoes a validation process. This step ensures that the email address uses the proper format (e.g., user@example.com). If the address format is incorrect, it’s invalid.
• DNS record check – The verifier checks that the domain contains a valid MX or A-type record, which is required to complete a real-time SMTP check later.
• Spam trap check – The email address or list is scanned for known spam signatures to detect known spam trap email addresses.
• SMTP check – Unlike pinging, a Simple Mail Transfer Protocol check involves the verifier attempting to communicate with the server via SMTP to determine whether an IP address is reachable.
• Additional threat checks – If all prior checks pass, the email address is valid. However, we continue testing to determine if it’s an abuse email, on a global suppression list, a catch-all, a disposable email, or belongs to a toxic domain.

Lastly, there may be difficulty verifying certain email addresses based on the server configuration. In these cases, ZeroBounce will reattempt validation by testing from different IPs.

For an example, consider this case study with The Links Guy.

The Links Guy is a link-building agency with a 10% email bounce rateⓘ. For context, anything higher than 2% is a flag for ISPs and hurts your sender scoreⓘ. After cleaning his list with ZeroBounce, he’s reported that his campaign bounce rates are consistently 1% or lower.

ZeroBounce Email Verification: A step-by-step guide

To help you avoid email bounces, here’s how to verify an email address or list with ZeroBounce’s email verification tool.

From the ZeroBounce dashboard, click Validate. Follow the steps for the option you choose below.

Single or batch email verification

1. Enter a single email address or a batch of up to 25.
   
   
2. Locate your results on the right. You can download the results by clicking the ‘Export to CSV’ button.

Bulk email verification

1. Upload your file using the drag-and-drop box. Or, select a file from one of the cloud-based drives.
   
   
2. The following menu will ask if you wish also to include ZeroBounce's Catch-all Scoring or Activity Data services. These are useful for gaining greater insights regarding the quality of your verified email addresses.
   
   Check the boxes, or click to continue.
3. ZeroBounce will begin to validate your list file and provide an estimated time until completion. No need to wait, as the platform will automatically deliver an email notification when it’s completed.
4. Click to download your results file. ZeroBounce will provide a one-time encryption key to open the downloaded file. This measure ensures that your data remains private and secure.

Using an integration

ZeroBounce allows you to integrate its email verification tool with 60+ platforms, including HubSpot, Salesforce, Mailchimp, and various ESPs, website builders, and CRMs.

To connect an integration, select one from the list on the left. Alternatively, you can visit the ‘Integrations’ tab from your dashboard.

The process for connecting an integration varies by platform and type. However, most are simple and involve these steps:

1. Select your integration.
   
   
2. Enter the API key provided by your integrated platform for your account.
   
   
3. Hit connect. ZeroBounce will sync with your account and automatically retrieve your email list data.
4. Select one of the available lists and click Validate to get results.
   
   

For step-by-step instructions regarding a specific email verification integration, visit the documentation.

Real-time email verification API

By adding the ZeroBounce API to your website, platform, or any page with a signup form, you can automatically verify an email address.

1. Use the API code in the documentation for your preferred language.
   
   You can also test the API by entering the following URL in any browser window:
   
   https://api.zerobounce.net/v2/validate?api_key=replacewithyours&email=valid@example.com&ip_address=156.124.12.145
2. From your ZeroBounce dashboard, select API. Then, click “Create a new API key.
   
   
3. Add this unique API key to the email verification APIⓘ where it says “YOUR_API_KEY.”
   
   

The email verification APIⓘ will automatically check email addresses entered into the associated field. If an email is valid, the user can submit it. If it’s invalid, the user will receive an appropriate error notification.

ZeroBounce's real-time email verification API

Clean Your Email List with ZeroBounce

If you want to know how to verify an email address, keep these essential points in mind:

• Email validationⓘ checks the syntax and format of the address.
• Email verification works alongside validation, performing necessary DNS records and SMTP checks to ensure that the address is deliverable.
• Email verification is required for mass senders to reduce bounce rates and preserve sender reputation.
• A dedicated email verification service is the only reliable method for verifying large lists with consistent accuracy.

ZeroBounce can verify your email addresses with a 99.6% accuracy guarantee. Try it today – create a free account and receive 100 free email verification checks monthly!