Why you can’t use a Gmail or Yahoo address to sign up for Postmark

When you sign up for a Postmark account, we ask you to use a work email. If you try to sign up with an address from a public domain like Gmail or Yahoo, you are met with this error message: Sorry, we don't allow email addresses on public domains such as Gmail and Yahoo. Please use your work email on a private domain. 

And if you reach out to our support team, you might hear that using free providers like Gmail or Yahoo can be viewed as spoofing, and that you need to sign up with a domain you control since the domain will be used as your sender signature.

We know this can be a point of confusion, or even frustration, especially since other providers don’t ask for the same thing. But a big part of our delivery efforts, and the reason why our deliverability is better than other ESPs’, is encouraging good email behavior on our platform and preventing bad emailers from messing things up for everyone.
Asking for a professional email address is one of the ways we make this happen.

Your domain says a lot about your business—and whether it can be trusted to send good emails #

Our mission at Postmark is to get emails delivered quickly and reliably, so we pay a lot of attention to who our customers are. For example, we make all folks who sign up fill in a form that explains how they plan on using Postmark, and then manually review each submission.

Yes: it is exactly as much work for our team as it sounds, but it’s also a crucial step of our process. If we determine that someone is not going to take good care of our IPs, we don’t allow them on the platform.

The domain you use when you sign up tells us a lot about who you are as a business and how you might use Postmark, and it’s one of the things we check when vetting new accounts. Generic, free email addresses from Gmail or Yahoo give no real details about who someone is, what they do, and what they could be using Postmark for; they also don't really reflect professionalism or help portray your company as a legitimate business.

We know this may complicate things, especially if you are a designer or developer who has lots of clients—but it’s a necessary step we take to protect our existing customers.

Sending from Gmail or Yahoo fails DMARC and causes bounces #

The other reason we ask for a work email address is that we tie your Sender Signature to a domain you control, whereas using free providers like Gmail or Yahoo can be viewed as email spoofing, fail DMARC, and cause bounces as a result.

[Quick recap: email spoofing is any sort of tactic used to trick an email recipient into thinking they received email from someone they know or trust. It can be as simple as changing the email sender’s display to look like a message is coming from a specific person or company, or as complex as registering a lookalike domain and start sending on its behalf.]

The type of spoofing Postmark is trying to avoid, and DMARC is protecting against, is the unauthorized use of a domain you don’t own.

In most cases, people who use a Gmail address are not maliciously trying to spoof Gmail or deceive recipients into thinking they are someone they are not. Still, trying to send from gmail.com through a mail server that Gmail has not authorized is, well, not authorized.

Right now, Gmail has a ‘p=none’ DMARC policy, so delivery of your emails won’t always be affected; but SPF and DKIM will fail alignment for DMARC, which will often result in receivers rejecting emails. Meanwhile, Yahoo, AOL, and other Yahoo-owned freemail domains have a ‘reject’ DMARC policy, which means that only approved mailservers can send on behalf of those domains. Third-party ESPs, like Postmark, will see bounces/rejections from all receivers—which is why preemptively block them for use as a Sender Signature.

In a nutshell, by asking you not to sign up with a Gmail or Yahoo address, we’re trying to avoid the future bounces and rejections you’d get by sending DMARC non-compliant mail.

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So here you have it: to ensure that Postmark keeps its stellar deliverability record, we need to verify that you’re authorized to send email from that domain through Postmark. And since you’re probably not the CEO of Google or Yahoo, we ask that you sign up with an email address from a legitimate business domain you own 😉