We take our responsibility of sending your business-critical application emails seriously. In order to maintain our high level of reliability, time to inbox, and deliverability, we continually monitor the type of email that is sent and received with the Postmark platform. This monitoring ensures that the messages on our infrastructure follow a set of guidelines based on our experience and certain requirements set by internet service providers.
So how do we define messages that are a good fit for Postmark? Our guidelines broadly fit into two main principles, outlined below.
Principle 1: Separate your email traffic
Sending bulk email and transactional email from the same IP can cause reputation issues since these are two different types of email.
To support transactional and bulk email, Postmark separates email traffic through Message Streams. Transactional and broadcast (bulk) traffic does not mix in Postmark, including IP ranges. Splitting email traffic this way helps ensure all your application emails get to their destination quickly and reliably.
We define transactional email as email triggered by some kind of user action. These messages can be sent through Transactional Message Streams. This includes, but isn’t limited to, emails such as:
- Welcome emails
- Reset password emails
- Comment notifications
- Weekly digest emails
- Order confirmation and tracking updates
- Receipts and invoices
We define broadcast email as email sent to many recipients at once. Broadcast messages often contain the same content for all recipients. These types of messages must be sent through Broadcast Message Streams. Some examples of these emails are:
- Product update announcements
- Updates to Terms of Service
Principle 2: Send good email
Once we’re sure that emails are a good fit for the Postmark platform, there are a few more things we look at as we monitor accounts to make sure we keep our reputation high with service providers. Here are some tips for things we encourage customers to keep an eye on and improve over time.
- Send high quality email. Ensure your transactional email has value to customers (and, by implication, high engagement) and that your list management, content, other sending practices are in tip-top shape for your broadcast messages. You’ll find plenty of great tips and examples in our email design guides.
- Keep spam complaints low. To avoid delivery issues to ISPs, spam rates should stay below 0.1% (1 complaint for every 1,000 emails sent). For more details on how to ensure low spam complaint rates, check out our article on troubleshooting email delivery issues.
- Keep bounces low. Bounce rates should not exceed 10% on all emails sent, which is a limit set by ISPs. Make sure you only send messages to email addresses that exist. Only send messages to active users and prune your email list of old inactive users, don't use Postmark to clean up your email list.
- Set up email authentication. We encourage all senders to set up SPF, DKIM, and DMARC to ensure good deliverability.
If your email fits within the two principles outlined above, we’d love for you to try out Postmark. You’ll find that our deliverability is unmatched, our support is amazing, and our platform is a pleasure to use.