Top 10 Email Marketing Platforms (2026)
Ranked on published customer counts and market position. Only three of the ten publish a number you can check — which is itself the most useful finding here.
Read this first. There is no standardised, comparable usage metric across this market. Vendors publish whichever number flatters them — registered accounts, monthly active users, paying customers, enterprise logos — and those are not interchangeable. Treat the order below as a research shortlist, not a league table.
The ranking
| # | Platform | What it is | Adoption signal | Our review |
|---|---|---|---|---|
| 1 | | SMB, newsletters, ecommerce | Claims “millions of customers” but publishes no count | Not yet reviewed |
| 2 | | CRM with email automation | 306,446 customers as of 30 June 2026, across 135+ countries [ir.hubspot.com] | Not yet reviewed |
| 3 | | Email, SMS, WhatsApp and CRM | Multi-channel suite with a strong European SMB base | Not yet reviewed |
| 4 | | Small business and nonprofits | Long-established brand with a large review footprint | Not yet reviewed |
| 5 | | Ecommerce, Shopify, DTC | Built around purchase data rather than lists | Not yet reviewed |
| 6 | | Advanced automation and CRM | Over 180,000 customers in 170+ countries [activecampaign.com] | Not yet reviewed |
| 7 | | Creators, newsletters, SMB | Competes on simplicity and price rather than depth | Not yet reviewed |
| 8 | | Email, funnels, webinars, courses | Pairs automation with creator monetisation tools | Not yet reviewed |
| 9 | | Ecommerce email and SMS | Focused on Shopify and WooCommerce sales flows | Not yet reviewed |
| 10 | | Newsletters and small business | One of the longest-running tools in the category | Not yet reviewed |
The ten in detail
1. Mailchimp
Entry point for people who have never sent a campaign; templates and defaults do most of the thinking. It says only that it serves “millions of customers”, publishing nothing you can audit. Under Intuit ownership its public positioning leans toward small-business commerce more than toward deep marketing automation. Reasonable if email is one task among many; weaker if segmentation and lifecycle logic are the core of the job.
2. HubSpot
Among the few vendors here that report a customer count, HubSpot disclosed 306,446 customers as of 30 June 2026, spread across more than 135 countries in its Q2 2026 reporting. That transparency comes packaged: email is one module inside a CRM suite, and the value case depends on adopting the surrounding platform. Teams wanting a standalone sending tool may pay for scaffolding they rarely touch, and migration later is seldom trivial.
3. Brevo
Formerly Sendinblue, Brevo is among the European-headquartered options on this list, and it argues for consolidating broadcast campaigns and application-triggered mail under one account rather than splitting them across vendors. It publishes no customer figure you can check. Consider it when data residency in Europe matters, or when you resent paying separate suppliers for one function. Look elsewhere if you need deep ecommerce reporting or a large agency ecosystem around the product.
4. Constant Contact
Constant Contact has long been aimed at the same buyer: the local business, association or nonprofit where nobody’s job title includes the word marketing. Support and hand-holding carry more weight in its pitch than automation depth, which is honest positioning rather than a flaw. No customer count is published. If your list segmentation is simple and someone needs to be walked through a send, it fits; if you want branching logic, check how far its automation actually goes before you commit.
5. Klaviyo
Klaviyo is built on the assumption that your email decisions should be driven by store data — what people browsed, bought and abandoned — rather than by list membership. That makes it coherent for retail brands and awkward for B2B or media businesses whose signals look nothing like a cart. It reports no customer total publicly. Budget accordingly: check whether pricing scales with the contacts you retain rather than the mail you actually send.
6. ActiveCampaign
The other vendor here willing to state a figure: ActiveCampaign’s About page claims more than 180,000 customers across 170+ countries. The product’s centre of gravity is the automation builder rather than the campaign editor, which suits teams that think in conditions and branches. That same orientation is the cost — someone has to own the logic, keep it documented, and unpick it when a flow misfires. Underused, it can end up an expensive newsletter tool.
7. MailerLite
MailerLite competes on restraint. The proposition is a tool a solo operator or small team can pick up quickly and keep using without a specialist, which matters more than feature parity when nobody has time to administer software. It discloses no customer numbers. The trade is obvious at the ceiling: complex multi-brand setups, heavy compliance review or intricate segmentation will eventually outgrow it, and the exit is easier to plan early.
8. GetResponse
GetResponse has grown outward from email into adjacent marketing tooling, which is the whole reason to look at it and also the reason to be careful. Bundled components rarely match the specialist tools they displace, so the maths only works if you genuinely retire the ones you are already paying for. Judge it as a suite, not as a sending engine. No customer figure is published for comparison against rivals.
9. Omnisend
Omnisend addresses the same retail buyer as Klaviyo but from the smaller-merchant end, pitching multi-channel messaging to teams without a dedicated retention hire. That framing is the qualifier: outside ecommerce, much of what you are buying may go unused. It publishes no verifiable customer count. Worth shortlisting alongside Klaviyo if your store’s requirements are conventional; less convincing once your data model or catalogue starts behaving unusually.
10. AWeber
AWeber is a veteran of this list, and longevity is genuinely part of the case — sending infrastructure with a long operating history, aimed at solo operators and small businesses who want the mail to leave and little else. Nothing about customer numbers is disclosed. The counterpart is pace: set against newer tools, expect the interface and roadmap to feel unhurried. That is a trade worth making only if stability outranks capability for you.
How to choose from this list
Read the absence of numbers as information. Only HubSpot and ActiveCampaign put a countable customer figure on the record here; everyone else asks you to take scale on faith, and Mailchimp’s “millions” is a marketing phrase, not a disclosure. That does not make the quiet vendors worse — it means you cannot rank this category by adoption, so rank it by fit instead. Start with where your data lives: a store, a CRM, or a spreadsheet of subscribers. Then ask who will own automation logic day to day, because unmaintained flows are a common failure point, often more so than deliverability. Finally, test export before you commit. The cost of leaving an email platform is paid in list history, and it compounds quietly.
Where the figures come from
Every number in the table above was read off a page published by the vendor itself, on 27 August 2026. Figures without a source link were dropped rather than repeated on our own authority.
- HubSpot — 306,446 customers as of 30 June 2026, across 135+ countries ir.hubspot.com · published Q2 2026 results, 5 August 2026
- ActiveCampaign — Over 180,000 customers in 170+ countries activecampaign.com
Figures we did not publish
- Mailchimp — Mailchimp’s About page says only “millions of customers around the world”. Intuit does not break out Mailchimp customers in its filings, so there is no checkable figure to print.
Editor's note
Seven of these ten publish no customer count at all, and that gap is the story. HubSpot has to disclose its number because it is a public company filing quarterly results; ActiveCampaign volunteers one; everybody else describes their scale in adjectives. So read the order below as market presence rather than measured size, and be sceptical of any article that ranks this category by user numbers — those numbers are mostly not published. One narrowing note: if your list is tied to a storefront, Klaviyo and Omnisend deserve to rank higher than a general-purpose ranking can justify, because purchase-triggered flows are the whole job rather than a feature.