Sending to unverified email addresses enough times can ruin bounce rates, damage the sender's reputation, and get you blacklisted.

The remedy is simple—make email verification a standard practice. We can verify an email manually or using tools to automate the process. In this guide, we’ll take a look at both and get a deeper understanding of the following:

  • Why do we need to verify email addresses?
  • Manual email verification methods
  • Automated email verification
  • Best practices for verifying an email

The Importance of Email Verification

As mentioned, email verification should be standard. It’s one of the fundamental requirements for cold email campaigns.

Without a proper verification process, entire campaigns are set up for failure. But with a system in place, you get the following benefits:

Verified Email List

A verified email list means every address is active. In short, your emails can land in an inbox, not in the ether.

If addresses aren’t verified, sending accounts are susceptible to high bounce rates, damaging email reputation. We want this improved.

Email Reputation Boost

Email reputation is a metric that we, unfortunately, can’t track. But email providers have their factors that account for it.

Most include bounce rates, open rates, and email sentiment—how recipients engage with an email.

Better Engagement

When you email leads, you want them to interact with your emails. This won’t happen when the address doesn’t exist.

Validating emails means data from key metrics like engagement rates are accurate. With high engagement rates, deliverability improves.

Improved Deliverability

Deliverability is the percentage of emails that land in inboxes. We can ensure high deliverability with email warmups and verification.

Domain authentication, optimized subject lines, and avoiding spam trigger words also improve deliverability. With healthy deliverability rates, the risk of being blacklisted is reduced.

Protection from Blacklists

Email verification alone can’t 100% guarantee protection from blacklists—but it's a great place to start. Remember, sending to invalid addresses equals hard bounces.

Imagine cold emailing 1,000 leads with 40% of emails hard bouncing. That signals email providers that your accounts are untrustworthy.

Now that we understand the importance of verification, let’s look at the strategies we can use to verify emails manually and with tools.

How to Verify an Email Manually

Manual email verification takes time. However, a hands-on approach can improve personalization as you do in-depth research on a lead. So, if you want to verify email addresses manually, try out the following:

Checking for Typos

You rarely see typos in an email for high-value leads, especially in B2B or SaaS. Most of these emails are also formal with similar formatting. Emails like “[email protected]” are common in these industries.

Review the emails against the data you have for your lead list. The names (if they use their name) and company should match. The next thing we need to do is to send a test email to see if it bounces.

Sending Test Emails

Most email providers warn or notify you if your message bounces back. A quick way to check is to view your sent tab. For example, Gmail will show this message when an email is invalid:

email verification methods

You can always try verifying the domain when you can’t verify the email. This allows you to know at least where to send your email instead.

Verify Domain

Verifying domains confirms if your lead is associated with a legitimate business or organization. You can use the Whois Domain Lookup tool for domain verification.

All you need to do is enter the domain name. If the domain exists, then you can email subdomains like [email protected]. But if that fails, you can try verifying through social media.

Social Media Verification

Businesses that want to build an online presence have their emails publicly available on social media platforms like Instagram, Facebook, or Linkedin. Verifying emails through social media confirms if there’s a real person behind the email.

Finding Verified Leads With

how to verify an email

Imagine running a cold email campaign. You’re going to need an email list of potential leads. That’s going to cost money.

After getting the list, you must verify it with another tool—an extra expense. Then, you also need to pay for the email marketing tool to help you scale campaigns.

With Instantly B2B Lead Finder, you don’t need to pay extra for your lead list and validation. All the leads are pre-verified from a database of over 80,000,000 B2B leads.

All you need to do is use the advanced filters to match your buyer personas or ICP and pay for leads that are already verified. You can specify roles, locations, company names, or industries.

There’s even an option for looking up leads based on keywords like B2B SaaS, Job Positions, or Technologies. So, if you want to find verified leads worldwide, try Instantly B2B Lead Finder today!

Automated Email Verification

Doing manual verification methods can work out for a handful of leads. But to scale email verification, you must automate verification using the right tools. Here’s what we recommend:


millionverifier homepage

MillionVerifier is one of the most trusted names in bulk email verification, claiming 99%+ verification accuracy. It follows a comprehensive verification process and includes the following features:

  • Duplicate removal from an email list
  • Email syntax verification
  • Domain verification
  • SMTP tests
  • Smart verification to remove false-positive
  • Grey list testing

All you need to verify your emails is to upload your list. You can easily integrate MillionVerifier into 17 of the most popular email marketing platforms to streamline workflow.


  • $37 for 10,000 never-expiring verification credits
  • $129 for 100,000 credits
  • Automated verification with marketing platforms for $15 extra


mailcheck homepage

MailCheck supports both email and phone verification. MailCheck utilizes social media, search engines, and public databases alongside validation algorithms, unlike other verification tools.

It also provides manual verification moderation for in-depth validation. Simply upload your email list, and you can get bulk verification instantly.


  • Pro Plan: $10/mo. For 1,000 email validations ($0.005 per overcharge)
  • Agency: $30/mo. For 5,000 email validations ($0.004 per overcharge)
  • Enterprise: $90/mo. For 20,000 email validations ($0.003 per overcharge)
  • Custom pricing

Reeon Email

reoon email

Reeon is another crowd favorite that boasts a 99% email verification accuracy. It uses domain verification, SMTP requests, and unique verification algorithms to ensure accurate results.

When you upload your email list, you can choose from several verification methods to fit your requirements. And you can integrate Reeon into CRMs like Zapier to support other campaigns.


  • Free Tier: 600 credits per month
  • Lifetime Credits: $11.90 for 10,000 credits. (0.0007 per verification overcharge)
  • Daily Credits: $9/mo. 500 credits/day. (0.0005 per verification overcharge)

Bulk Email Checker

bulk email checker

Bulk Email Checker tests the validity of email addresses based on SMTP. They also test emails against 17+ factors to ensure the highest accuracy.

First, the tool removes all duplicates from your email lists and tests the emails against an updated list of disposal email providers for free.

Next, it checks for DNS entries and filters role accounts. Finally, Bulk Email Checker runs a deep SMTP cleaning to check your lead’s email provider if their email exists.


  • $2.95: 1,000 email validations
  • $5.95: 5,000 email validations
  • $9.95: 10,000 email validations
  • $23.95: 25,000 email validations

You only need to pay a one-time fee for each tier. Bulk Email Checker offers up to 25,000,000 email validations for $3,299.95 if you want to scale email validations.


neverbounce homepage

Neverbounce can clean and verify your email list at scale. Like the other verification tools, it uses SMTP and various proprietary methods to ensure accuracy.

Before cleaning, Neverbounce automatically scrubs your email list for duplicates for free. It can also remove potentially harmful emails, spam traps, and honeypots from your list.

Users also get instant bounce analytics. These data-driven insights can signal to marketers whether a list is ready for use.

Pricing: (Only Pay for What You Use)

  • $0.008 per email: Up to 10,000 validations
  • $0.005 per email: Up to 100,000 validations
  • $0.004 per email: Up to 250,000 validations
  • $0.003 per email: Up to 1,000,000 validations

Pricing: (With Cleaning Automation)

  • $10/mo.: 1,000 emails
  • $49/mo.: 10,000 emails
  • $99/mo.: 50,000 emails
  • $159/mo.: 100,000 emails
  • $249/mo.: 250,000 emails

Key Takeaways

Verifying an email address is crucial for the success of any email campaign. Verified email lists protect our sending domains’ reputation, improve deliverability, and boost engagement.

We can verify email addresses manually or with the help of automation tools. To make the most of our validation campaigns, consider the following best practices:

  • Use domain lookup, social media, or search engines to validate emails manually.
  • Typos can appear in our email list; clean them before running campaigns.
  • Verification tools automate email verification at scale.
  • Most of these verification tools charge per validated email.

If you want a tool that can scale your email campaigns and find verified, high-quality leads simultaneously, Instantly has you covered! Sign up for a free trial today!