Cold Email · · 9 min read

9 Email Checker Tools For Maintaining Healthy Lead Lists

Email checker tools help validate email lists, ensuring the highest possible deliverability in every campaign. Here are nine leading options to consider.

email checker

Email campaigns have three key stages: prospecting, offer creation, and outreach. Each stage can be automated, measured, and scaled. Here’s where most email marketers fail—scaling. 

Scaling isn’t just about adding more leads to campaigns. If you want to scale, the offer must be personalized, the sending volume must be sustainable, and lead emails must be verified. 

That’s where email checker tools come in. They ensure that the emails you’ve collected during prospecting are legitimate emails that belong to the right people. 

Sending to unregistered email addresses hurts your deliverability and domain reputation. If you scale without an email checker, you could end up on a blacklist.

The question now is, which email checker tool should you use? In this article, we’ll be going over the A-Z of email verification:

  • What is an email checker tool
  • How to choose the correct email checker
  • X email checker tools to consider this 2024
  • How to streamline the email verification process 

What is an Email Checker

Lead quality is the foundation of the entire sales process. You wouldn’t want to spend time personalizing a sales email for a high-value lead only to discover that it bounced. 

Now, imagine scaling that to hundreds or thousands of leads. Even with automation, you’ll end up with low deliverability rates and a bad email reputation.

Email checkers prevent this issue by determining whether an email address is valid, active, and can receive emails. However, not all active email addresses are the same. 

With an email checker, you can identify if an email is a disposal address, role address, accept-all address, or fake address. Here’s how it works. 

How Does an Email Checker Work?

Simple email checkers validate an address by extracting the MX records and then connecting to a mail server over SMTP (simple mail transfer protocol). They can also simulate a message to validate the existence of the email address they’re currently checking. 

Most modern email checkers go above and beyond this simple process. Some even have a proprietary system for validating an email address. But in most cases, the verification process follows these steps:

Syntax Check

The first step in email verification is determining whether the email follows the proper syntax or standard format for every email sent to [email protected]

Domain Verification

When email checkers identify proper syntax, they check if the domain exists and whether it can send or receive emails. They do this by checking the DNS records and domain-related data.

Disposable Email Detection

Millions of disposable emails are used daily. These could be a person’s burner email, or a tool scammers use for malicious email activity. 

Role Account Detection

If you get your hands on a company lead list, you’ll often run into role email accounts. Examples of these are [email protected] or [email protected]

You don’t want to send cold sales emails to these accounts. Most of these are behind company firewalls and are likely to be sent to spam. 

Greylist Check

Greylist checks identify whether an email address can bypass greylisting filters. Unlike blacklists, greylists temporarily block an email from the sender. 

Then, it requests that the email be sent again. Due to the additional requests, sending to these addresses might soft bounce and delay the delivery of your emails.

How to Choose the Right Email Checker For You

Email checker tools ensure the success of outbound campaigns and protect your sending accounts and domains. But with hundreds of email checkers available, how can you choose the best one for your business? Here’s what you need to consider: 

Bulk Email Verification

Email marketing is a numbers game. Your email checker tool must have bulk email verification features, at the very least. Turnaround time is also an essential factor. Some tools can verify 10,000 emails within 3-10 minutes, while others take much longer. 

ESP Integrations

The best email checker tools can easily be integrated into your email service provider (ESPs) or sales lead management tools

This helps streamline the import and export process of adding leads from your email list to your email checker tool. Find a tool that works for both, so you won’t have to jump between apps. 


Email checkers should provide a report highlighting the percentage of good, bad, and risky emails on your list. If the report reveals a high rate of harmful or risky emails, you must consider changing to a higher-quality lead source. 

Real-time Email Verification

Inbound lead generation efforts can generate a list of highly interested prospects. However, site visitors may enter fake or disposal email addresses on your lead capture pages to access gated information. 

To avoid these issues and ensure prospects enter the correct email address, you can use APIs from email checker tools to do real-time email verification on your lead capture forms. It can help you filter out fake email addresses, role accounts, or regular email accounts. 

For example, suppose you’re offering an in-depth case study. In that case, you can gate the content behind a form that only takes email addresses from official business domains, streamlining prospecting and lead qualification.  

Email Deliverability Tools

Email checkers are only part of your overall strategy. You also need tools that ensure your emails land in the right inbox. That’s where deliverability tools come in. 

Some email checkers come with deliverability tools to analyze content, find spam words in your emails, or blacklist monitoring tools.

One of the most essential deliverability tools is automated warmups. Tools like can warm up unlimited domains, helping you scale sustainably without compromising deliverability. 


If your customer base is in the EU, you must use GDPR-compliant tools to avoid issues related to an individual’s privacy and security. 

In a nutshell, GDPR regulates the collection, storage, and processing of user data, which includes email information. 

Delivery Guarantee

Most email checkers provide a 95% to 99% deliverability guarantee. But don’t mistake this as the deliverability of your campaigns. This metric means that between 95% to 99% of the emails in your list can receive emails. The rest is up to you. 

To ensure maximum deliverability, consistently warm up your sending accounts, avoid spammy email practices, and include personalization in your emails.  

9 Email Checker Tools to Consider This 2024

Now that we know what to look for, here are nine email checker tools that fit the criteria. Find what works for your business and consider your overall goals and budget. 


email checker tools

Instantly offers a one-stop shop for all prospecting, outreach, and personalization needs—no need to switch between apps. You can choose a monthly verification plan or a one-time top-up for verification credits. These credits don’t expire. 

To verify leads with Instantly, simply upload the CSV file of your lead list. You can also verify leads already added to your Instantly campaign. Go to the “Leads” tab and click “Verify Leads.”

If a lead’s email address is invalid or risky, Instantly won’t send emails to it by default. But you can allow sending to risky emails in the Campaign options.


mailer checker home

MailerCheck combines email verification and deliverability testing in one app. You can even use the MailerCheck API to integrate its verification tool on your lead capture pages. 

There are options to verify a single email address and bulk email verification. After confirming your leads, it will give a report showing the valid and risky emails and highlights why. 

If your list contains duplicate emails, MailerCheck won’t charge you extra credits for them. Free users even get 200 credits when they sign up. 

Aside from verification tools, MailerCheck also has deliverability tools such as inbox insights, spam content checkers, DMARC monitoring, and blacklist monitoring for your domain. 

Pricing: $10 for 1,000 credits


million verifier

MillionVerifier is one of the most popular email checker tools on the market. It offers fast validation times and a 95% deliverability guarantee. 

It has single—and bulk email verification and API integration capabilities and can be integrated with 17 of the most popular email service providers (ESPs). 

Like most verification tools, MillionVerifier categorizes emails as Good, Bad, and Risky. It also gives a detailed report and lets you download a segmented lead list. 

Pricing: $4.90 for 2,000 credits


neverbounce home

Neverbounce offers many powerful features, even for free users. Its analysis tool can help you estimate the health of your lead lists and identify lists that benefit from validation.

This feature also comes in handy for users who want to save credits. If you will make the most of what you pay, use the free list analysis tool first, then bulk validate your lists. The only downside is that free users only get five free credits. 

When you get the reports, Neverbounce categorizes your email list into valid, accept all, unknown, disposable, and invalid email addresses. You can choose to include or ignore specific segments when exporting. 

Pricing: $8 for 1000 credits


emailable home

Many businesses have multiple lead sources. Emailable streamlines the verification process by connecting with your chosen email marketing platform and sources the leads there. You can also upload lead lists in multiple formats (CSV, xlsx, or txt). 

With Emailable, bulk verification only takes a few minutes. There are also options to automate the verification process. One area where Emailable could improve is the UI and reporting. 

Overviews of lead list verification campaigns don’t have labels, which may confuse some users. But this won’t be much of an issue if you already have the labels memorized.  

Pricing: $25.50/month or 0.006 per credit


bouncer email checker

Bouncer is one of the most intuitive and straightforward email checker tools. It can bulk verify up to 250K emails using proprietary algorithms backed by AI. 

Bouncer can identify spam traps, toxic email addresses, and even email addresses of people who actively report email-sending accounts. 

Pricing: $50/month or $0.008 per email


clearout home page

Clearout boasts an impressive 98%+ deliverability guarantee. It uses 20 validation checks when verifying an email address, including spam trap detection, MX record checking, and greylisting checks. 

Clearout can also be integrated with outreach platforms like HubSpot, allowing real-time email validation for chat support. 

Aside from being an email checker, Clearout also has a Chrome extension for lead generation on LinkedIn

Pricing: $31.5/month or $0.007 per credit


mail meteor homepage

MailMeteor’s email checker checks the email format, domain name server, MX records, and SMTP to validate. They also have subject line test tools and automated spam word checkers. 

There is also a free single-email validation tool on their site. However, this only checks the validity of the email based on the format, MX, and SMTP.  The email will be tagged as valid if the domain has a valid MX and SMTP. 

Pricing: $9 per month (up to 15,000 emails)


Hunter has one of the most comprehensive email verification tools on the market. It also has a lead finder, enrichment, and public email finder tools. However, these comprehensive features come at a steep cost, making it not ideal for small businesses with a tight budget. 

Pricing: $34 per month paid annually 

Streamlining the Email Verification Process

Email verification costs also scale if you want to start scaling your prospecting. Even when automated, verification still takes time, especially if you do it in bulk. 

What if you could skip the email verification process altogether? That’s where Instantly B2B Lead Finder comes in. 

Instead of sourcing leads from third-party apps or sites, Lead Finder users gain access to 160 million pre-verified B2B Leads. All that’s left is building a high-converting email campaign sequence. 

To streamline email validation, you can skip email checker tools and use Instantly B2B Lead Finder to access over 160 million pre-verified leads that fit your exact ICPs and buyer personas. Try it out today! 

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