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Cutting through the noise when choosing an ESP

Picking an Email Service Provider is a mental tug of war: but here are the things you need to know before you make a final decision. Read more...



Picking an Email Service Provider is a mental tug of war: you’ll be working with that ESP a long time, and you want to make sure that the service is going to meet your needs perfectly. But there’s no avoiding the pressure from the business to figure it out ASAP. That app you’ve been working on is missing email capabilities and needed to deploy yesterday…or maybe that email server you’ve been using just can’t keep up with all the emails that need to go out every day.

You have a lot of choices, and it’s not an easy decision to make. To help you out, I’m going to cover a few things that you should pay close attention to as you go through the process. Even if it’s not a comprehensive list, these are the must-haves that an ESP should be ready to provide…otherwise, it could be a red flag – and you might want to back away slowly.


This is a big one, and something we want to set the record straight about. I can’t tell you how many times we’ve talked to a prospective client and they’ve been made false promises. It usually goes something like this:

“Hey Nick, this other ESP says they provide 100% deliverability. What can Mailgun get me?”

Any time you hear an ESP tell you this, you run! This is something we’ve discussed in a previous post, and the reality is that the ESP plays a much smaller role in deliverability than you think. Most of that outcome falls on the sender. What you should look for when choosing an ESP is one that will tell you what it takes: good list acquisition practices , list scrubbing, paying attention to your analytics, etc. To get the best deliverability possible, you should look to one that will work with you and provide guidance on how to get there. Don’t fall for F.U.D. and empty promises, as they will only set you up for failure.


The reputation an ESP has in the email community is critical to the overall success they have in delivering your email. If an ESP is known for harboring Spammers, that reputation will follow them and affect the way ISPs view them. This could lead to large blocks or filtering problems that affect you as a sender. If the ESP is known to take an active stance against spammers and they monitor their network to keep these bad actors out, it will show in the relationships they have with ISPs. At Mailgun, we care so much about this that we have an entire Reputation team dedicated to fighting spammers – which consists of engineers, as well as AUP and Deliverability specialists.


As a sender you’re looking for results, right? When you choose an ESP, one of the most important questions you need to ask yourself is “How can I measure the success I’m having with my email campaigns?”. If you are looking at an ESP that doesn’t offer a way to easily track the performance of each and every campaign you send, you might as well just throw your money away.

This way you’ll know which ones perform best (send those more!), or which ones your subscribers are complaining more frequently about (stop sending those right meow!). Be nimble and make changes based on the behavior of your subscribers. At Mailgun, we know how important this is – which is why we did a major revamp of our Analytics feature set last year.


The email landscape is changing frequently, and because of this it’s hard to stay ahead of the curve. When you are on the search for a new ESP, make sure you choose one that is knowledgeable in all things email. Take a look at the resources made available to you. Is the documentation easy to follow? Are there blog posts, videos, guides, or how-to articles you can learn from? How about their infrastructure? What MTA do they use? How do they process your data?

These are great probing questions you should ask before making a final decision. Any kind of specialized services an ESP offers will also speak to their expertise. If the idea of having a deliverability expert on your side sounds appealing, feel free to take a look at our managed service. It pairs your team with a deliverability expert to help you plan ahead or circumvent issues you may be encountering at the moment.


When you buy a new car, you look at all the features included to see if it solves for your needs. There is no reason why you shouldn’t be doing the same thing with an ESP. Sure, any ESP can help you send email (I hope). But what else can they do for you? Just like having a drop-down DVD monitor for your kids while you drive creates a great experience, an email validation service that ensures you are capturing valid email address from the start is a must-have to create a great experience.

If all you can do with an ESP is send messages – and you don’t really get much else – you will be left feeling like you have to do it yourself to get it right.

At Mailgun, we offer things like the aforementioned analytics and email validation service, but also features like Rapid-Fire in case you need to send millions of messages REALLY fast, and Routes to handle and parse incoming messages.


As you can see, that’s a lot of things to consider when making an educated business decision like choosing an ESP. But if you have an idea of what to look for, you’ll be much more successful at cutting through the noise and focusing on what’s going to be the right fit. I hope this information will help you in your search, and if you have any questions on this please let us know. Whatever you do, don’t fall for the 100% deliverability guarantee!

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