Mailfloss Review

mailfloss is a relatively new email verification service that has some unique properties and awesome features that make it an attractive fit for many businesses looking to get maximum email deliverability and ROI from their email marketing efforts.

What makes mailfloss different is that it automatically finds, verifies, removes, tags, and fixes invalid emails from your email lists before they become a problem.

This is a hands-off process and requires only a one-time setup that doesn’t take more than a couple of minutes to complete. And the best part is it doesn’t require any developers to setup.

All that’s required is a supported email service provider. Luckily for us, mailfloss supports many of the most popular email service providers. The full list of mailfloss supported email service providers is:

  • ActiveCampaign
  • AWeber
  • Campaign Monitor
  • Constant Contact
  • ConvertKit
  • Drip
  • HubSpot
  • Infusionsoft
  • Klaviyo
  • MailChimp
  • MailerLite
  • Moosend
  • Ontraport
  • Sendinblue
  • Sendlane


According to mailfloss, they plan on adding many more integrations this year. And don’t be afraid to contact them and request the email service provider that you use if it isn’t supported.

The founder, Martin Wong, is very accessible and really listens to mailfloss customers. mailfloss was born out of his frustration with existing email verification solutions. According to him:

“I was a busy email marketer in a small startup with limited resources. I was too busy to do email verification and existing solutions were cumbersome, expensive, and time-consuming. I knew it was important but it was something I dreaded doing. And I’d always forget to do it before important email marketing campaigns – exactly when it’s needed most! I had enough, so I set out to build the most convenient solution available. It had to be affordable, accurate, and set and forget. This was non-negotiable.”

Let’s get into some of the highlights of mailfloss.

Easy setup

Setup is a breeze with mailfloss. Their onboarding is great and easy to follow. Everything is intuitive and there are plenty of tooltips and guides to help you along the way if you need additional help. You can have everything setup in a matter of minutes, and from then on it’s set and forget. Everyday mailfloss will do automatic cleanup for you, which is a huge time-saver and prevents invalid emails from stinking up your email list.

Daily, automatic removal

This is a great feature unique to mailfloss among email verification services. mailfloss will cleanup email addresses everyday. That means new subscribers are checked and verified and removed if they fail verification. The nice thing about this feature is that mailfloss let’s you either manually review the invalid emails inside of their dashboard first, or you can choose to let mailfloss handle everything for you automatically.

Flexible options

There are many options you can optionally use if you want. They have different aggressiveness settings to let you determine how hard you want to floss your email lists, something unique to mailfloss. This gives you a lot of control and flexibility into how mailfloss handles your email lists, which is a nice touch.

High accuracy

Of course, an email verification service needs to be accurate for it to be useful, and mailfloss is one of the best when it comes to accuracy. They’ve recently released a new verification engine and the results are stellar. It has 15 different categories an email can fail on as well as statuses they fall under. These are:

  • Invalid – These emails fail syntax checking and are invalid.
  • Spam – These email addresses are flagged as spam accounts.
  • Role – Emails are of role, such as administrator. Although they may be valid, role emails tend to perform poorly and may affect deliverability rates.
  • Banned – Emails belonging to a banned keyword or domain. These are swear words and others that tend to be fake and perform poorly.
  • Disposable – These emails are from disposable email services that are temporary. They are not worth emailing and will affect deliverability.
  • Illegitimate – The domains of these emails do not have valid mx records and thus do not accept emails.
  • Available – The domain for the email address is not active, is showing as parked or as available for sale. The email addresses are likely to be invalid.
  • Unverified – The emails appear to be good but we could not verify because the domain is not responding.
  • Blacklisted – Emails contain blacklisted keywords defined by the user.
  • Bounced – Emails sent to this address hard bounce and should not be emailed.
  • Complained – These addresses have marked emails as spam in the past and are more likely to do so in the future.
  • Nonexistent – These email addresses do not appear to exist based on our tests.
  • Deactivated – These addresses have been deactivated and are not able to receive incoming emails.​
  • Accept All – These email addresses at this domain look good, but any email address at this domain look good and cannot be verified completely.
  • Inbox Full – The inbox of this email address is full and can’t currently receive email addresses.

And the statuses these categories fall under are Undeliverable, Risky, Unknown, and Passed.

Pricing and Plans

mailfloss has a 30 day money-back guarantee and a 7-day free trial, both of which are some of the most generous offers we’ve seen in the email verification space.

Subscription plans

The Lite plan is $17 for 10,000 email verifications per month. It also includes 1 integration connection, Zapier access, auto-unsubscribe or auto-delete, 10% off any prepaid credit purchases, and more.

The Business plan is $49 for 25,000 email verifications per month. It includes everything in the Lite plan, 10 integration connections, 15% off prepaid credit purchases, and more fine-grained controls over what can get automatically removed. A really nice point with the integration connections is mailfloss supports connecting the same email service provider multiple times. So, in theory, you could connect 10 different MailChimp accounts. Or you could also connect a MailChimp account, a Klaviyo account, 2 Ontraport accounts, etc.

And finally the Pro plan is $200 for 125,000 email verifications per month. It includes everything in the Business plan plus unlimited integration connections, 20% off prepaid credits, and the ability to tag or update custom fields for email service providers that support it. This is powerful because it allows you to segment and run workflows and automations based on mailfloss data. Combined with Zapier and you can do some powerful stuff.

mailfloss offers a 7 day free trial on all of the above subscription plans. This is as generous an offer as we’ve seen in the email verification space. Subscription plans are only available with a supported email service provider and are best for those businesses that want hands-off, headache free, fully-automated daily email verification.

Prepaid credits

On the other hand, if you only need to do a one-time cleanup, prepaid credits may be better suited for you. mailfloss offers some of the most affordable rates we’ve seen, and an extremely generous 30-day money back guarantee. The prices for prepaid credits are as follows:

  • 1000 credits for $4
  • 10,000 credits for $20
  • 50,000 credits for $80
  • 100,000 credits for $150
  • 250,000 credits for $250
  • 500,000 credits for $400
  • 1,000,000 credits for $600
  • 2,500,000 credits for $1300

Please also remember there are additional discounts with the subscription plans of 10%, 15%, and 20% on the Lite, Business, and Pro plans, respectively.

According to mailfloss, a common scenario many customers prefer is to subscribe for daily verification of new email subscribers that’s covered in their subscription, and then purchasing additional credits as needed to clean their entire database, which mailfloss recommends doing every 3-6 months or more. Their decay protection feature runs monthly to clean the entire database automatically.

Pros of mailfloss include:

  1. Set and forget solution that cleans your email lists everyday from invalid emails before they become a problem.
  2. One-time setup with no developers required.
  3. Automatically unsubscribes, deletes, tags, and fixes invalid email addresses including hard bounces, complainers, typos, spam accounts, and more.
  4. Prevents email lists from going stale with their decay protection feature.
  5. Highly accurate detection with their flossing engine.
  6. An exciting roadmap of upcoming features including a real-time API, webhooks, more integrations, and auto-fixing invalid emails.

Cons of mailfloss include:

  1. They don’t currently have an API, but mailfloss says they expect their public API to be released this year.
  2. Not the fastest solution available, but mailfloss says they plan on tackling this next. Normally this isn’t a problem since everything is hands-off and handled automatically so you aren’t waiting around for a report, anyways.


mailfloss is the most convenient email verification service available. Not only is it convenient – it is also very affordable, highly accurate, simple to use and also has many powerful options if you choose to take advantage of them.

That makes mailfloss an attractive email verifier for many online businesses that want an edge in their email marketing campaigns without any additional resources, overhead, or work involved.

If you use a supported email service provider, we highly recommend giving mailfloss a try.


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