Why delivery speed matters
If you talk to someone about email deliverability these days, youâll probably end up talking about inbox rates. What percentage are going to the inbox? What percentage to spam? What percentage is missing? These are all good and important, but they arenât enough. How quickly they arrive is just as important. Which begs the question, why donât we hear more about it? We have some theories, but regardless of the reasons, we think that needs to change.

Sending transactional email looks easy on the surface. Choose an email service provider (ESP), connect, and send emails. However, thereâs much more to it than whatâs on the surface. Due to spam, phishing, and other email scams, Internet Service Providers (ISPs - like Gmail and Yahoo) are more cautious than ever. If youâre not careful, thereâs no assurance your emails will arrive in the inbox at all, let alone quickly.
We feel strongly that fast delivery to the inbox is a core service for every email service provider, not an add-on or up charge.
How slow transactional emails cost you money #
To appreciate the value of getting emails to the inbox quickly, letâs take a step back and discuss why speed is so critical for transactional emails by looking at examples where missing or delayed emails directly affect your bottom-line.
Forgot password. Lost sale. #
Letâs say you run an e-commerce business. Imagine a customer who ordered from you some time back and setup an account. The customer returned, and theyâve added a few items to their cart. Theyâre ready to checkout, but when they go to login, theyâve forgotten their password. Fortunately, your site is a paragon of usability and your visitor easily requests a password reset. Then they go to their inbox and wait. And wait. But after more than a minute, a different important email arrives in their inbox, they get distracted, and they move on to handle that email. If all goes well, theyâll eventually receive the password reset email, and maybe theyâll finish the purchase. But if they donât, youâve lost a sale.
Whereâs my license key? Iâll just ask support. #
Another all-too-common example happens when software companies send license keys via email. A visitor successfully purchases some software and immediately goes to their inbox to get the license key and start using their newly purchased software. And then they wait. And wait. Of course, you already have their money, so you may not think this is a problem. But then when that license email doesnât show up, they email your support team to inquire about the status of their order. Multiply this process by 10's or 100âs of support requests, and youâll quickly see how delayed emails can lead to unnecessary support costs. At high enough volume, this can mean having to hire more people. One customer switched to Postmark for precisely this reason and saw their support requests from lost or delayed receipt emails disappear almost entirely.
Death by 1,000 cuts #
Unless you operate on a large scale, the costs of the delays may not be obvious. But stories like these happen every day because too many applications take email for granted. You may assume that hitting âSendâ is good enough, and that it will get there when it gets there. But your choice of ESP can have a significant impact ensuring that the emails arrive promptly. Service providers just need to be more forthcoming about the true quality of their delivery.
The dirty little secret of email service providers #
Thereâs a dirty little secret among email service providers. ESPs get paid for sending emails, not delivering them. So, while most ESPs do care about delivery, they donât have the financial incentive to do an amazing job of delivery. Their incentives lie primarily with quantity not quality. So long as quality is good enough, they still get paid. As a result, thereâs little incentive to focus on speed or transparency. And as a customer, the impacts on your bottom line may not be immediately obvious.
As customers, weâve come to accept this. While inbox rates are beginning to be a regular part of the discussion, itâs secondary and doesnât address delivery times. Since ISPs behave as a black box in order to protect their spam-fighting tactics, ESPs frequently claim that delivery is ultimately out of their control. As a result, they focus on generating revenue by pushing volume or selling dedicated IP addresses.
Some providers even charge extra for âimproved deliverability.â This enables their pricing to appear more competitive on the surface, but firmly illustrates the difference between sending email and delivering it. We feel strongly that fast delivery to the inbox is a core service for every email service provider, not an add-on or up charge.
Most ESPs boast about the volume of email sent but never say a word about their inbox rates or delivery speed. Remember, spammers could brag about sending billions of emails too.
Bulk marketing email vs. Transactional email #
The focus on volume leads most email service providers to support sending bulk email. Thereâs a lot of money in it. Unfortunately, sending bulk marketing emails and transactional emails from the same place means that your important and high value transactional emails can end up in line behind larger bulk marketing campaigns. So at times, your transactional emails could be delayed significantly unless youâre segregating your bulk and transactional email streams.
ISPs are also great at distinguishing bulk email versus transactional emails. When they see email from one source going to thousands of users all at the same time, they know that itâs bulk, and they may throttle it for inspection or filtering. They also factor engagement into reputation, and since transactional emails have significantly higher engagement, this benefits the reputation of servers and domains that are only sending transactional email. Over time, ISPs build a history of which IP addresses and domains are used to send bulk, and they begin to give email from those servers lower priority. In short, if your bulk and transactional are coming from the same place, your transactional emails will suffer.
If bulk marketing emails create so many problems, why donât ESPs do something about it? The answer is simple. With low prices, they have to move a lot of quantity to make money. So most ESPs desperately need the revenue from bulk campaigns regardless of the overall impact to deliverability. Most ESPs boast about the volume of email sent but never say a word about their inbox rates or delivery speed. Remember, spammers could brag about sending billions of emails too.
At Postmark, we focus exclusively on transactional email and donât allow bulk marketing email. This specialization means our costs are a little higher, but it also means that we donât suffer from any of the drawbacks of bulk marketing email. We maintain a better reputation with ISPs, and our inbox rates and delivery speeds are some of the best in the industry. Theyâre so good that weâre not afraid to share them and will be publicizing all of the details on our new status page.
Itâs time for increased transparency #

Each and every ISP maintains their own rules and handles throttling and delays differently. So for ESPs to stay on top of things, they have to constantly monitor delivery speeds and inbox rates for each of the major providers like Gmail, Yahoo, Hotmail, Outlook, AOL, and iCloud. However, while most ESPs have some of this information, they donât share it because it doesnât always paint a flattering picture.
We think itâs time for ESPs to step up and become more transparent about their success and failure rates. Weâve been taking small steps in this direction for some time by exposing the fine-grained detail of delivery events for each message. That helps you troubleshoot individual messages, but it doesnât help you know how Postmark is doing overall on deliverability. We always wanted to share more insight, but it takes time to do this right.
Next week, weâll launch a brand new status page and status API to help address this. Youâll be able to see our delivery rates for all of the major ISPs (Gmail, Yahoo, Outlook, AOL, and iCloud). Right next to that information, youâll also be able to see our average delivery speed for each of the major ISPs as well. Weâll also be sharing the methodology, tools, and details behind our calculations so that itâs crystal clear how everything works.
Itâs long overdue for email service providers like Postmark to become more transparent with their performance. We understand that itâs not easy, but we believe that when you select an email provider, youâre not just paying for a dumb pipe or a service that merely sends emails. Youâre looking for a service that delivers them.