November 14, 2022

Email Ad Server vs. ESP Ad Serving: Which Is Right For You?

Publishers today have a huge opportunity to drive revenue from one of the most direct and trustworthy channels on the web: email. Especially now that a growing number of people are checking their email every day and paying for subscriptions, publishers can tap into these engaged audiences using email ads and monetize their content.

The question is, which tools should they use to serve and optimize email ads at scale?

As it stands, publishers have two main options for email monetization: email service providers (ESPs) and email ad servers. They may sound similar — and present a bit of a tongue-twister if you say them together — but each offers unique benefits and features, which publishers can use to streamline their ad operations and drive engagement.

Here, we’ll unpack just what you need to know about ESPs and email ad servers, so you can understand their greatest strengths and find the right solution for your business.


What is ESP ad serving?

Many publishers already use an email service provider (ESP) to manage their email marketing content. With an ESP, they can send email newsletters to their subscriber lists and track performance.

While ESPs are built for managing organic email content, publishers might also use them to serve email ads. This means either their email marketing team or ad trafficking team will hard-code ads directly into their email templates.

What are the benefits of ESP ad serving?

ESP ad serving offers many benefits for email advertisers, including:

  • One-to-one content matching. Ads are customized directly for each email placement. That means they can be tailored to closely match the content and styling of each email, including fonts, colors, and spacing. This is particularly helpful for creating native email ads, which are designed to blend in with their surroundings and yield less disruptive user experiences.
  • Fluid responsiveness. Since ESP ads are created as HTML CSS and images, they can automatically scale and respond based where they’re displayed, such as on mobile or desktop. That also means advertisers don’t have to worry about text-wrapping being warped as the screen gets larger or smaller. By hard-coding the ad in an ESP, you can ensure your ad fits seamlessly into your email template and displays correctly, regardless of device.
  • Pre-send ad completion. Ads are hard-coded into emails before they’re sent, giving teams an opportunity to lock in each campaign and move onto their next projects.

What is an email ad server?

An email ad server is a platform built specifically for launching and managing email ad campaigns. With email ad servers, publishers can automate the process of selling and placing targeted ads in their newsletters.

More specifically, email ad servers use data and algorithms to deliver personalized ads at scale. They pair the right advertisers with the most relevant placements and readers to increase results. Many email ad servers also offer additional capabilities like real-time campaign reporting, ad backfill, and insights for optimization.

What is an Email Ad Server?

What are the benefits of an email ad server?

There are many advantages to launching campaigns through an email ad server, including:

  • Saved time and resources. Ad servers automate ad distribution, so you don’t have to hard-code each placement, and you can make the ad fill process more efficient.
  • Flexibility for adjustments post-send. Since ads aren’t hard-coded, you can make changes even after you click “send.” For example, you might adjust a spelling error, swap in an updated image, or run multiple creatives for A/B testing.
  • Enhanced targeting and personalization. Ad servers can easily divide your subscriber lists into unique audience segments for personalized campaigns.
  • Integrations for multichannel reach. Your email ad server might be integrated with your web ad server, so you can manage email, website, and mobile app campaigns all from the same platform.
  • Robust campaign reporting. Ad servers can track performance — including opens, clicks, and impressions — across individual campaigns and target goals.

Email ad server vs. ESP: Which solution is best for your business?

The answer to this question will depend on your business needs, resources, and goals. If you want to hard-code each ad for one-to-one content matching, you might choose an ESP to monetize your emails. Or if you want to streamline your workflow with automation and enhanced targeting options, you might decide to use an email ad server.

Ultimately, it’s important to understand the unique benefits of each solution, so you can choose the right monetization tool for your business and continue driving revenue from one of the most powerful channels on the web today: email.

Contact us to learn more!