What your ESP can (and can’t) do for your deliverability

Deliverability Podcasts

In episode 11 of the Deliverability Defined podcast, Melissa and I discuss the ways that your ESP can help your deliverability, but also all of the things your ESP can’t help with.


What’s an ESP?

ESP stands for Email Service Provider. An ESP is a platform that allows you to send emails to your audience. For example, ConvertKit is an ESP. There are thousands of ESPs out there and they all tend to each have their own strengths and weaknesses, as well as specialties.

When shopping for an ESP, everyone wants an ESP with “good deliverability”. While some ESPs can help you perform better, there are also things ESPs can't do for your deliverability.

What your ESP can do for your deliverability

A lot of the work ESPs do for customers' deliverability happens behind the scenes. Here are the major ways reputable ESPs contribute to the deliverability of their customers:

  • Managing the entire delivery infrastructure
    • This is super complex and it's all taken care of for you! Your ESP handles:
      • IP management
      • connection rates
      • bounce and deferral handling
      • complaint feedback loops
      • and more
  • Managing bounced subscribers
    • Removing invalid or low-quality subscribers from your list is key to healthy deliverability. If you're using a good ESP, they will automatically suppress bounced subscribers from your list for you.
  • Managing complained subscribers
    • Your ESP will set up feedback loops with any mailbox provider that has one. A feedback loop allows the ESP to know which subscribers have marked a message as spam. Your ESP can then mark the subscriber as complained and suppress them from your list. This is another necessity for having healthy deliverability.
  • Monitoring blocklistings
    • If the domain or IP you use to send emails is on an impactful blocklist, you'll likely have deliverability issues. A reputable ESP should be monitoring blocklists around the clock and be equipped to handle them if they happen. We have an entire episode on blocklists so be sure to check that out if you haven't already.
  • Building industry relationships
    • A reputable ESP should have at least one person on their team who has relationships with people who work for the various mailbox providers and blocklists, as well as an industry presence as a whole. These relationships can help some deliverability issues get solved quicker or more efficiently.

While emails will appear to come from your sending domain, your ESP’s domain is often used in the background and in all of the links, as well as the IP. If an ESP has all of the items above in a healthy place (we can vouch that ConvertKit does), then when it comes to deliverability, the ESP brings healthy IPs and domains to the table.

The right ESP can help your deliverability by doing the heavy lifting behind the scenes to provide you with a healthy infrastructure to send from. However, this isn't enough to get your mail delivered to the inbox. Mailbox providers will also be looking at your domain's sender reputation, and your deliverability will depend on a healthy reputation.

What your ESP can't do for your deliverability

An ESP can only do so much to provide a healthy deliverability. Each sender using the ESP will experience unique spam filtering, open rates, click rates, etc. You hold more power than you might know.

As we've discussed in many different episodes, deliverability will still come down to following the best practices for a healthy sender reputation.

No ESP can fix the deliverability of a sender with bad practices, but a bad ESP can hurt the deliverability of a good sender

What to look for in an ESP

Once you've decided an ESP has all of the features you need, don't hesitate to ask about their deliverability and compliance support.

One important thing to ask is whether you'll have customer support from a deliverability specialist if you run into an issue. This is something we have in place at ConvertKit and it's so important. Deliverability is very technical, and each ticket can take a lot of investigating. Be sure the ESP you use has high-quality deliverability support in place.

You can also ask the ESP for more information about what their deliverability and compliance team does to make sure they're keeping their sending infrastructure healthy for customers.

Once you've started sending from a reputable ESP, you'll need to be sure your list health, content, strategy, etc. are in place for healthy deliverability. If you haven't heard our episode on sender reputation, that would be a great one to listen to next.


To receive email notifications when new episodes of Deliverability Defined are available, or to submit topic suggestions, sign up to our email list. 

Get Notified About Future Episodes!

To receive email notifications when new episodes of Deliverability Defined are available, or to submit topic suggestions, sign up to our email list.

Sign Up

Alyssa Dulin

Alyssa is a Deliverability Lead located in Nashville, TN. She loves helping senders reach the inbox of their subscribers. Outside of work, Alyssa enjoys traveling, indoor cycling, and spending time with family.

The future belongs to creators

ConvertKit helps creators like you take their projects from idea to reality. It's never been easier to build an audience and grow a business. And you can do it all for free.

Launch your next project