This page will briefly outline our integration with Postmark.

Transactional Email Service

All emails (including both Zenlogin transactional emails and login email notifications sent by Zenlogin to your users, on your behalf) are fulfilled by Postmark.

Postmark is a leader in transactional emails, and is used by some of the most well known privacy and security products and services online.

We specfically chose them because of their reputation and reliability for over 10 years. With that said, we'd like to outline exactly how we use them so you can fully understand our integration. We use Postmark to fulfill the following actions:

Login Email Notifications

When we detect a suspicious login, we do a number of things. One of them is, depending on your account's settings, send an email to that user on your behalf. This is where Postmark comes in. We use them to send that email.

We make sure that open tracking and link tracking are turned off.

For security reasons, these emails are kept on Postmark's servers for up-to 45 days, after which they're deleted.

Sender Signatures

In addition to simply sending off the emails, we use Postmark to facilitate something called "Sender Signatures". This allows us to send emails from your email address.

We think this is an important part of security because if we were to send the emails from our own email address (eg., your users might get confused (and possibly think it's a phishing attack). And to be fair, they'd be right to be confused: they don't have a relationship with us. They have a relationship with you.

So to address this, we use Postmark's Sender Signatures API to allow you to give us access to a specific email address which we can then use to send Login Email Notifications.

For example, you may want us to send Login Email Notifcations from the email address To do this, you simply log into your Zenlogin account and head over to your Account Settings. From there, you enter your desired email address, and Postmark will send you an email to confirm that you have access to that email account.

At any point, you can choose to delete this Sender Signature from your Zenlogin account, at which point we will permantly delete it from our Postmark account, thereby revoking our ability to send Login Email Notifications on your behalf.