Email Marketing Software Market Share & Usage Statistics (2026)

Mailchimp. It runs on roughly 526,000 of the 2.47 million live websites where we detect an email marketing platform, about 21% of the category. Klaviyo is second at about 17% and SendGrid third at about 13%. The top five (adding Mailgun and Amazon SES) hold roughly 71% between them; the other 60 tools we track share the rest.

By number of live websites detected, the order is Mailchimp, Klaviyo, SendGrid, Mailgun and Amazon SES, then Brevo, Mailjet and MailerLite. Two things to keep in mind: this ranks by websites, not by subscribers or revenue, and it counts what a crawler can see (signup forms, tracking scripts, sending domains), which is why API-first senders like SendGrid and Mailgun rank alongside campaign tools.

We detect an email marketing or email sending platform on about 2.47 million live websites, across 65 tools. 'Live' means the site responded and carried the tag in our latest crawl; sites that go dark or remove the tag drop out of that count at the next crawl, which is why the totals move month to month.

Slowly, on our numbers. Mailchimp is still the clear leader, but over the latest 30-day window it lost roughly 9,800 net domains (about 3% of its base) while Klaviyo lost about 3,400 and the developer-facing senders (Amazon SES, Mailgun, SendGrid) all gained. Read the losses as sites where the Mailchimp tag stopped appearing, not confirmed cancellations: small sites churn out of the crawl too. Over 90 days the category as a whole is slightly up.

Mailchimp is the general-purpose option: newsletters, basic automation, a free tier, and a huge base of small businesses and nonprofits. Klaviyo is built for ecommerce, with deep Shopify and WooCommerce integrations, revenue attribution per email and SMS in the same tool, which is why it's the second most-detected platform (about 416,000 live sites) despite being younger. If your emails are tied to orders, Klaviyo; if they're not, Mailchimp or one of the cheaper suites usually does the job.

Over the latest 30 days the net gainers are Amazon SES (about +3,300 domains), Mailgun (+1,900), SendGrid (+1,400), MailerLite (+1,300) and Mailjet (+770). MailerLite is the only campaign-style suite in that list; the rest are transactional or API senders. Over 90 days the same names lead, so it isn't a one-month blip.

Campaign platforms (Mailchimp, Klaviyo, Brevo, MailerLite) are for newsletters, automations and audience segments, and are used by marketers. Transactional services (SendGrid, Mailgun, Amazon SES, Mailjet) send one-to-one emails triggered by your app, such as receipts, password resets and alerts, and are used by developers. Both leave a detectable footprint on a website, so both appear in this category, and plenty of sites run one of each.

Most campaign tools have a free tier capped by contacts or daily sends (Mailchimp around 500 contacts, MailerLite around 1,000 subscribers, Brevo a daily send limit) and paid plans that start at roughly $10-20 a month and scale with list size. Transactional senders price per email instead: Amazon SES is around $0.10 per 1,000 emails at the time of writing, with SendGrid and Mailgun offering free monthly allowances and volume tiers. Your contact count, not the vendor, is the main cost driver.

For a small business that isn't a store, MailerLite, Brevo and Mailchimp cover almost every case, and MailerLite is the one of the three currently growing in our data. For a store, Klaviyo (or Omnisend, the smaller ecommerce specialist) will pay for itself faster than a general tool. Our ranking measures how many websites run each tool, not customer satisfaction, so pair it with a review site before you buy.

Klaviyo is the ecommerce-first option and the second most-detected email platform overall; Omnisend is the smaller specialist built for the same audience. Both plug order, browse and cart data straight into email and SMS flows. Mailchimp works with Shopify too, but if abandoned-cart and post-purchase flows are the point, start with the two ecommerce-native tools.