The Most Popular Email Service Providers (ESPs) in 2024

Robert BrandlRoberta Phillips

By Robert & Roberta

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most popular esps

It is notoriously difficult to obtain reliable customer data for email service providers.

In a recent LinkedIn post, which got over 5,000 impressions, I tried to come up with a ranking based on Datanyze data.

However, the data felt a bit…wonky.

esp market share linkedin

For example, who has ever heard of AcyMailing? And why are Brevo and ActiveCampaign missing from this list?

To create a more realistic ranking, I tried to find the data the ESPs publish themselves about their user numbers. Fortunately, almost all the SMB-focussed email service providers publish some sort of user data.

The 17 Most Popular ESPs

Based on the latest self-reported data, here's a breakdown of the user numbers and (hypothetical) market share for the most popular ESPs:

ESP Number of Users Market Share (Hypothetical) Country Source Comment
Mailchimp 11,000,000 70.86% USA Mailchimp website “11 million businesses use Mailchimp.”
MailerLite 658,530 4.24% USA / Lithuania MailerLite website “Join 658,530 creators and businesses using MailerLite.”
Constant Contact 650,000 4.19% USA Constant Contact press release “The company helps more than 650,000 customers.”
Brevo 500,000 3.22% France Brevo website “500K Customers globally”
Benchmark 500,000 3.22% USA Benchmark Email website “Over 500,000 users
GetResponse 400,000 2.58% Poland GetResponse website “400,000+ customers worldwide”
CleverReach 370,000 2.38% Germany CleverReach website “370,000 customers worldwide”
Campaign Monitor 250,000 1.61% Australia Campaign Monitor website “250,000 companies worldwide love Campaign Monitor.”
Hubspot 216,000 1.39% USA HubSpot Newsroom “Over 216,000 customers” (Includes non email marketing customers)
Keap 205,600 1.32% USA Keap website “205.6 K Users” (31.5K customers)
ActiveCampaign 150,000 0.93% USA ActiveCampaign website “150,000+ small businesses around the globe use ActiveCampaign.”
Klaviyo 143,000 0.92% USA Klaviyo investor report “Over 143,000 customers are using Klaviyo.”
Omnisend 100,000 0.64% Lithuania Omnisend website “100K+ happy customers worldwide”
AWeber 100,000 0.64% USA AWeber website “AWeber is an email marketing service provider helping over 100,000 customers.”
Campaigner 100,000 0.64% USA Campaigner website “over 100,000 businesses
Email Octopus 83,000 0.54% UK Email Octopus website “We've helped over 84,000 organisations.”
ConvertKit 56,513 0.36% USA ConvertKit Baremetrics page Baremetrics stats (real customers)
Mailjet 40,000 0.26% France Mailjet website “With over 40,000 customers in 150 countries”

Data originally collected in June 2024.

Similar to the Datanyze data I used in my LinkedIn post, Mailchimp is absolutely dominating the email marketing market by their number of users. They were one of the first companies to introduce a freemium plan, and that also seems to be the reason for their huge popularity. However, it's unclear how many of them actually pay.

MailerLite is another ESP that offers a (generous) free plan. The number we were able to gather refers to users rather than customers.

Constant Contact and Brevo are the first ones that talk about customers. If they really have more than half a million customers, that's enormous.

A bit of a surprise is CleverReach, which isn't widely known internationally. They are likely the biggest ESP in German-speaking countries (Germany, Austria and Switzerland) and claim to have almost 400K customers, which is almost as big as GetResponse.

More expensive ESPs like ActiveCampaign, Klaviyo and Keap don't have the same user numbers as the more popular ESPs; however, we can assume that their margins are considerably higher.

Limitations of the data

It's important to note that the data comes from the websites of the ESPs themselves. While this is the best data available, it should be taken with a grain of salt. The companies use different terms to describe their users. Some call it “users,” others “customers,” or “companies”, which can sometimes be misleading. A “user” or a “company” doesn't always pay for the service if there's a free tier available. A customer, on the other hand, indicates that money is being exchanged.

The best data, without a doubt, comes from ConvertKit. Their metrics are openly available in a Baremetrics dashboard along with their revenue and many other interesting business figures.

Unfortunately, we weren't able to find good data for Moosend, Drip or SendPulse. Moosend says, “Moosend is used by thousands of businesses”. We couldn't find any data for Drip. And SendPulse says this: “SendPulse reached 1 million 934 thousand registered users”, which seems unrealistically high, given their relatively small brand. Neither Google search volumes (based on Ahrefs) nor other data sources (e.g. Datanyze) indicate a high popularity that is that high.

The market share number you find in the table is hypothetical. It's based on user/customer numbers and doesn't reflect a monetary value. If sales were taken into account, players like Salesforce, Listrak or SAP emarsys might play a much bigger role.

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Based on all the data sources available, using the ESP's self-reported data seems most reliable.

Mailchimp continues to dominate the market with a significant lead, boasting over 11 million users. Other providers like MailerLite, Constant Contact, Brevo, and Benchmark also have substantial user bases, but they lag behind Mailchimp's impressive numbers.

When choosing an ESP, it's essential to consider not just the number of users but also the specific features and capabilities that meet your business needs. That's where we come in:

> Compare the best email marketing services

The authors

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Robert Brandl

Founder and CEO

Hello! I'm Robert, an email marketing expert with over 15 years of experience. After honing my skills at an agency by serving major corporations, I founded EmailTooltester as a passion project to help small and medium-sized businesses. Connect with me on LinkedIn where I regularly share my best email marketing knowledge.

Roberta Phillips

Marketing Manager

Hey, I'm Roberta! Having worked as a digital marketer for a host of online businesses, I've tried, tested, fallen in love with and despaired with so many marketing tools. I'm excited to help you find the email marketing and CRM tools you need to thrive.

Learn more about us

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09 Jul 2024 – Campaigner added, other small corrections

Our Methodology

This article has been written and researched following our EmailTooltester methodology.

Our Methodology