Best Email Service Provider (ESP) for Cold Email

You might be new to cold emailing, or perhaps you've been doing it for a while, and things just aren’t working as well as they used to. Either way, it’s not a bad idea to stop for a second and think about what email service you’re using. It’s easy to overlook, but honestly, it can have a bigger effect on how your emails perform than most people realize.
There was a time when you could simply create a regular email account and start sending messages without much hassle. That used to work fine. But now? Not so much. Things have changed, and if you want your emails to actually get delivered and seen, you’ve got to be a bit more thoughtful about how you approach it.
In this article, we’ll cover the best ESP for cold emailing and why choosing the right one is crucial to reaching the inbox instead of the spam folder.

What is an ESP? 

An Email Service Provider, or ESP, is what you use to send and receive emails. It handles all the background work to help your messages reach people’s inboxes instead of getting lost in spam.
ESP is like a digital post office. You write your message, drop it off, and the ESP takes care of getting it to the right place in the most reliable way possible.
It’s the same idea as mailing a stack of handwritten notes. You wouldn’t just drop them anywhere and hope they show up. You’d rely on a trusted system to make sure each one ends up where it’s supposed to. That’s exactly what an ESP does for your emails.

ESP and Cold Email Software: Is it the same? 

A lot of people think that the terms “ESP” and “cold email software” are the same thing. They don’t. It’s a common mix-up, especially in outreach work, but they serve two completely different purposes.
Your ESP is what actually sends the email. It’s what makes sure the message ends up in the inbox and not the spam folder. That’s its job. Without it, nothing gets delivered. Cold email tools are built for something else entirely. They help you manage campaigns, personalize at scale, and keep everything running smoothly. But they still rely on the ESP to do the heavy lifting when it comes to delivery.
You need both. One handles the sending, the other handles the strategy. Simple as that.

Choosing the Right ESP Matters More Than You Think

When you’re running a cold email campaign, your ESP isn’t just a technical detail. It’s one of the most important decisions you’ll make.
A reliable provider gives your emails a real chance of landing in the inbox. It supports your sender reputation and keeps things running smoothly as you scale. But if you choose poorly, problems can sneak in under the radar. Emails might start going to spam, and in some cases, your domain could suffer before you even notice.
If you’re aiming for real results, don’t treat your ESP as an afterthought. It’s not just about sending emails,  it’s about making sure they actually get seen.

Best ESPs for Cold Outreach and Their Cons

Mailpool

When it comes to cold email outreach, Mailpool stands out as one of the top-performing email service providers on the market today, and for good reason.
Mailpool is purpose-built for cold email. It’s fast to deploy, easy to manage, and optimized to work seamlessly with leading cold outreach tools. The setup process is refreshingly simple: connect your domains, or you can even purchase your domain at Mailpool, update the nameservers for your existing domain, create inboxes, and you’re good to go in less than five minutes.
Mailpool sets up SPF, DKIM, and DMARC for you right away, so there’s no need to handle any of it yourself. You won’t find yourself running checks again and again just to be sure things are working. It’s made to keep the setup process simple from the start, so your team can dive in without losing time on the technical stuff.
Beyond setup, Mailpool checks all the boxes that matter when choosing an ESP for cold campaigns:

• Strong deliverability and inbox placement
• High-volume sending capacity
• Scalable infrastructure
• Automated warmup
• IP reputation management
• Spam rate & Blacklist protection
• Affordable pricing
• Responsive support

Cons

Mailpool is purpose-built for cold email. But when it comes to transactional email or email marketing, it falls short. If you’re planning to send things like order confirmations, drip emails, or messages based on user actions, Mailpool might not be the right fit. It’s not really built for that type of email. You also won’t get the built-in tools that come with something like Google Workspace, like Calendar, Meet, and Drive. If your team is used to having everything under one roof, Mailpool might come up a bit short.

Google

Google Workspace is one of the top choices when it comes to email service providers for cold outreach because of its user-friendly interface and robust collaboration features.
Gmail offers high deliverability, making sure emails get to the inbox. It also has anti-spam and phishing protection. On top of that, it offers virus protection and advanced security measures while maintaining a strong sender reputation.

Cons

Google Workspace is a good choice for cold outreach. But there are a few things to watch out for. Spam filters can be quite aggressive, so bulk emails don’t always make it to the inbox. There’s also a daily limit of about 25 emails when reaching out to new contacts. That can create roadblocks for anyone trying to run a larger outreach campaign. On top of that, Google frequently updates its spam policies, so outreach strategies often need adjusting. It’s also on the pricier side and not built for scaling cold email efforts. For anyone relying heavily on outreach, these limitations are worth considering when choosing a platform.

Microsoft 365

One big reason people lean toward Microsoft 365 for cold outreach is how reliable it is when it comes to getting emails delivered. Messages that come from Microsoft’s servers usually have a much better shot at hitting the inbox, not the spam folder. That by itself can make a real difference. You’ve got threat protection, encryption, and compliance tools all working in the background to help keep your sender rep clean and your contacts’ info safe. It doesn’t matter if you’re just a small team or picking up momentum; it can handle both without a problem.

Cons

Microsoft 365 is one of the best email service providers for cold email. A notable challenge is the platform's variable sending limits. Unlike dedicated email service providers with transparent thresholds, Microsoft 365 imposes different caps depending on the different versions. These restrictions are not always clearly documented. Also, new users often need time to navigate their feature set and optimize workflows effectively. This adjustment period can delay outreach efforts, particularly for teams transitioning from other platforms.

Moving forward

Finding the right Email Service Provider can really shape how well your cold email campaigns go. Like with any job, using the right tool makes everything easier. A good ESP helps you reach people more effectively and gives you a better shot at getting responses.
It’s worth taking a bit of time to see what fits best for your goals. A setup that works for you can be the thing that gets your emails noticed instead of ignored.
If that sounds like something you’re ready for, check out Mailpool. It takes care of your email infrastructure fast, so you can get back to sending the stuff that actually gets seen.