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Deliverability

Deliverability services: Decoding deliverability with the experts

Trying to crack the email deliverability code can seem impossible if you aren’t really familiar with what deliverability is. And even if you’re a deliverability pro, implementing it within your email program can be subjective. Get the breakdown and insights from our deliverability pros in this post.

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Deliverability is like operating a ham radio – it’s been around a while but most people don’t know how to use it. Like a radio, deliverability relies on external factors to transmit messages. Where radios battle signal strength and interference, deliverability battles protocols and spam filters. The question is, do you know how to get your message out?

In 2025 Mailgun conducted its annual state of email deliverability report and asked senders their view on email deliverability and their grasp on what email deliverability means.

Out of the 1,100 people who took our survey, only about 5% described their job role as “Deliverability Specialist.” The truth is, there aren’t too many deliverability specialists roaming across the email landscape, even though we need them. So, if you’re like 95% of senders, read on to understand why you need high-quality deliverability expertise to support your email program.

Understanding the impact of deliverability

Email deliverability is just the act of getting your message into your recipient's inbox. That’s it.

What makes this seemingly simple act complicated are the differences between protocols and standards among mailbox providers, the filters set up to weed out spammers, and the increasing need for sender identity authentication.

But why is email deliverability so important? Well, if emails don’t land in the recipients' inbox and are not read...what’s the point of sending them?

According to survey respondents, the biggest benefits of prioritizing email deliverability are improved customer satisfaction and increased email ROI. Makes sense – after all, that is why we send messages in the first place. The goal of email communication is to market a service, convey a story, or transmit something that impacts consumers while also benefiting the business.

When it comes to numbers, email’s ROI is already high, but when you partner with an ESP it increases further. In Forrester’s Total Economic Impact (TEI) study commissioned by Mailgun to evaluate our platform and services in 2023, Forrester found that, over the course of three years, Sinch Mailgun delivered a 264% return on investment (ROI) and a $454K net present value (NPV).

ROI and customer satisfaction can tell us a lot about deliverability. It’s one thing to land in the inbox, it’s another to provide quality messaging to subscribers that leads to conversions or meaningful connections. Engagement is a bit part of the deliverability picture.

The challenges of email deliverability

Email deliverability is sensitive and can feel kind of superstitious. It’s like that old sailor’s adage, red sky at night, sailor’s delight, where subtle changes in atmosphere can be telltale signs of an incoming storm.

The biggest deliverability hurdles exist because mailbox providers, postmasters, and even ESPs all aim to automate the filtering of actual useful content from spam. It’s very easy to be mistaken for spam if you don’t know how to navigate deliverability, and this can greatly impact engagement.

In our deliverability survey, we found that:

  • 40% of senders who prioritize deliverability say the biggest benefit is Improved customer satisfaction.

  • Among senders who’ve been blocklisted, Delays for important messages was the biggest negative impact at 33.5%.

  • Another 22% said the biggest impact of getting blocklisted was Dissatisfied customers.

The number one challenge for senders is understanding all the elements at play. Email deliverability is ultimately built through a combination of technical requirements and engagement strategies that senders need to know about:

  • Sender reputation: Your sender reputation is like your email credit score, and it’s impacted by many deliverability aspects. Factor one is your IP address and domain health.

  • Authentication: Along with your IP/domain health, authentication is a major contributor to your sender reputation. Authentication protocols like SPF, DMARC, and DKIM help prove to ISPs that you are a legitimate sender by verifying your sender identity through certificates and encryption.

  • List health: List hygiene is key to good deliverability. In email, a clean list is built organically, not bought. Strong lists are regularly validated and maintained with tools like email verifications or processes like sunset policies to ensure that inactive users or invalid addresses don’t count against you.

  • Subscriber engagement: How your subscribers interact with your messages influences where ISPs place them in the inbox. If your users mark you as spam, you can bet that’s where you’ll end up landing. That’s why understanding and carefully monitoring email metrics is important.

But that’s not it. On top of knowing what impacts your deliverability, you need to understand the best practices across each of these areas. What’s the right way of building an email list? How should handle disengaged subscribers? What are the best authentication practices for your email program?

Finally, you need to be able to read your email metrics and track any slight fluctuation in engagement to detect potential issues. For example, a sudden increase in bounce rate can mean you might be on a blocklist, but it could also mean you haven’t properly warmed your IP, that you’ve purchased emails, or have suddenly increased your sending and the volume is being flagged as suspicious.

Navigating the ins and outs of email deliverability

As you’re probably realizing, deliverability can be a pain in the keester. Especially if it’s a relatively new concept to your team.

We’ve talked a lot about best practices and some of the elements that impact email deliverability. Now, let’s talk about how to implement it, what are some good deliverability resources, and when you should think about lighting up the bat signal.

Build a culture of continuous deliverability education

If you’re going to go it alone, we won’t stop you. Deliverability is something that can be learned and if you have the internal resources to dedicate, managing your email deliverability in-house can be successful.

Step one is to understand the basics. Take the factors of email deliverability we outlined earlier and look at your current sending practices. A great place to start is by analyzing what you’re currently doing that works well, and what might be hurting you.

Step two is to get a bird’s eye view of how deliverability works and is being implemented by senders on a larger scale. Staying connected and up to date on deliverability trends is key to ensuring you adapt your strategy to the latest developments from mailbox providers and consumer habits.

Wondering how to do that? We’ve got you covered:

  • Check out the Sinch Mailgun blog to stay informed: A great place to start learning about deliverability is by subscribing to our blog. We take deep dives into deliverability issues, commission reports, and break down industry trends and challenges.

  • Listen to the pros on Sinch Mailgun’s Email’s Not Dead podcast: There are many communications channels to choose from and some would say that email is a thing of the past. Our Email’s Not Dead podcast proves them wrong. Broadcast by our in-house deliverability experts, our podcast features insights by email leaders, security professionals, marketers, and developers.

  • Learn from your peers through our original research: In our 2023 State of Email Deliverability Report sheds light on the deliverability knowledge and practices that are being implemented, and the types of things you can do to stand out in the inbox.

Are you staying out of the spam folder?

The state of email deliverability 2025

Dive deeper into email deliverability with more from our exclusive report. Find out what hundreds of senders around the world are doing to reach the inbox and hear from experts who’ve spent their careers navigating this complex topic. Explore the insights now. No form filling required.

Partner with deliverability experts

For those with more complex needs or larger email volumes, learning deliverability can be really hard. And it’s not always a straight-forward science.

Deliverability success depends on an individual sender’s needs, but trying to craft a bullet-proof strategy when there’s a lot at stake can prove impossible without the right type of support and constant monitoring. That’s why sometimes, the best and most strategic solution is asking for help.

This is where deliverability services come into play. These services are generally offered by experts who have been in the deliverability trenches and have the information bank necessary to conquer deliverability issues – everything from warming IPs, to best sending habits, list cleaning practices, and real-time troubleshooting for challenges like a spam trap hit or a sudden blocklisting.

“Data has started to become the modern-day equivalent to a telephone switch board. There are so many points of data that a sender needs to pay attention to, and then know how to plug that data into their sending strategy. The job of a deliverability specialist is to help assist with untangling that data, understanding it, and prioritizing how it should be used. Additionally, there may be data that is not currently used that should be included in sender’s measurements and a specialist can help you find that as well.”

Jonathan Torres, Manager of the TAM team at Sinch Mailgun

Troubleshooting deliverability issues with a deliverability expert

If you’re sending important emails, then deliverability is the most important art (and science) to master. It improves the experience for your customers and recipients, which increases your engagement, ROI, and contributes to your overall reputation.

Using professional deliverability services not only helps you build the structure of your email program, but to monitor all of your email channels.

When an incident arises and gut-punches your email communications channel, it can impact both marketing and transactional email efforts, stopping your recipients from getting their password resets, confirmation emails, or shipment notifications, which can lead to a decrease in customer satisfaction and email ROI. Deliverability services equals a faster resolution.

In fact, The Forrester TEI study found that professional email deliverability services improved incident response time and resolution.

“Forrester applied a 50% productivity recapture to time savings for email deliverability issues, indicating that resources repurpose 50% of the time saved to value-add activities.” See the full results.

Sending an email is a lot more complex than just clicking a button and crossing your fingers for a high open rate. Get the help you need by enlisting the best deliverability experts to both build and monitor your email program. Check out Mailgun’s Deliverability Services and talk to a strategist today.

Learn about our Deliverability Services

Deliverability Services

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