How Does Catchall Verification Work?
Email verification was a commodity for the longest time -- all products did the same thing and produced similar results.
But recently, a dozen startups (Findymail, Prospeo, Scrubby, Leadmagic, etc) emerged claiming to do it "better" than legacy players. These companies have gotten a lot of attention, due to their claim that they can verify 50% more emails, which leads to larger email list sizes, which in turn leads to more revenue.
However, marketers using these services have noticed a lot more variance in results, both in terms of what percentage catchall emails they can verify and the accuracy of the results. They've also seen a big discrepancy in pricing, leading them to ask many questions...
In this article, we're going to answer all of these questions by doing a deepdive using research gathered over the past two years in the Delivery Lab.
What is Catchall Verification?
The "old school" way of verifying email addresses is "SMTP verification", which involves probing a remote email server to check if an email exists (this article goes deeper into this topic.)
Because this method works by exploiting a security vulnerability, it tends to only work for smaller organizations without IT teams and works about 45% of the time.
The remaining 55% of email addresses are categorized as "catchall" emails.
How do these email verifiers work?
Today there are four flavors of catchall verification available on the market (in addition to SMTP
1) App User Verification
What is App User Verification?
This is what most of the new email verification providers do today.
It involves building workflows that attempt logging into third party apps and seeing if there is some positive confirmation that an account with that email exists.
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How Does App User Verification Work?
Let's explore this with an example:
This error tells you that a user at some point created a Trello.com account with this email address. Because we know Trello only shows this message after a user verifies an account with a valid email in the signup flow, we can conclude that the email was valid at some point.
Similar workflows can be setup across many apps, including some email providers themselves (eg: the microsoft login flow)
Why Do Results/Accuracy Vary?
For this method to work, you need to use sites that have LARGE user bases, which are not provisioned by IT (eg: twitter, youtube, trello, etc) and which are explicitly created with work emails (eg: github usually won't work).
Furthermore, major providers like Google and Microsoft now either block these checks or even intentionally provide invalid/inconsistent results when they detect suspicious activity.
Finally, the bounce rate from these emails will vary because these third party apps aren't in sync with the target email server. For example, the target email may have existed at some point on twitter.com but if the user leaves their company, the twitter account will continue to remain long after the underlying email has been deactivated.
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[Want to continue reading the rest of this article? You can find it here on the Deliverability Blog]
Growth & AI Automation Expert | Founder LeadMagic | World's Best Email Finder
6 个月This is close but we aren’t claiming the claims Findymail or the other ones do. I personally never email catchall emails but I’m a bit of a catch all snob. We believe our methods are the best but that’s because we’ve been at it for a long time and have a feedback loop that no one else could even dream of. I would never guarantee a rate. It can be off by a factor of 100x.