Postmark

Time to Inbox is the length of time it takes from when an email is sent from a client until it is logged as delivered.

Time to Inbox data is refreshed every 5 minutes. We generate the TTI (Time to Inbox) data internally using an automated system powered primarily by our MailHandler gem, which we released under an MIT license. Every five minutes, we send an email with consistent content to each of the five major ISPs (Gmail, Yahoo, Outlook/Hotmail, AOL, and iCloud/Me.com). We then measure the time it takes between when the email was sent and when it is logged as delivered.

This approach gives us the closest estimation of when an email is delivered based on the factors that Postmark can control and conveys a more accurate measurement of performance for our customers.

For now, the short answer is that you can’t. While it’s very common for email service providers to measure and record the time to inbox, none (other than Postmark, of course) are sharing how long it takes for emails to get to the inbox. Rest assured, we’re very confident sharing these numbers because we know where we stand against other email service providers. Since we focus exclusively on transactional email, we have a distinct reputation advantage that helps ensure our emails get to inboxes incredibly quickly, especially when compared to providers who also offer bulk marketing email capabilities.

Absolutely. Great delivery is included for all of our customers, free or high volume. We don’t think that great delivery should be an add-on or up-charge, and we stand behind our email delivery on both our shared and dedicated IP addresses.