Customer.io vs MailerLite: how much is event-level depth worth?
MailerLite is the cheaper bill at every list size on its public selector: $89 a month at 10,000 subscribers on Comfort, against $145 for Customer.io Essentials at 10,000 profiles. What Customer.io adds for that difference is an events-and-objects data model, webhook-triggered automations and transactional email on every plan. What MailerLite adds is a free tier, landing pages, a website builder and a flat monthly cost that is easy to explain to a founder.
By Julian Pryor · Updated 7 Oct 2026
Short answer
If your email is mostly newsletters, announcements and launch campaigns, MailerLite does the job for less, and the free plan covers a start. If your emails are triggered by what a user does in the product and by billing events, Customer.io is the tool designed for it, and at 10,000 profiles the extra cost is $16 to $56 a month depending on the MailerLite plan you compare with.
What the bill looks like from 1,000 to 25,000
MailerLite's rows are its monthly-billed slider readouts for Comfort and Power; yearly billing takes 10% off, which its page shows as $10.80 and $22.50 at 500 subscribers. Customer.io's rows are Essentials readouts, billed monthly, and the 25,000 figure is the 20,000 readout of $235 plus 5,000 × $0.009. All were read on 7 Oct 2026.
| Audience | MailerLite Comfort | MailerLite Power | Customer.io Essentials |
|---|---|---|---|
| 1,000 | $19 | $39 | $100 (selector starts at 5,000) |
| 5,000 | $49 | $69 | $100 |
| 10,000 | $89 | $129 | $145 |
| 25,000 | $179 | $239 | $280 |
The differences against Comfort are $51 at 5,000, $56 at 10,000 and $101 at 25,000. Against Power they are $31, $16 and $41. Power, the tier with unlimited automations and unlimited emails, is the fairer comparison for a lifecycle program, and against it Customer.io costs a modest premium. Against Comfort, which caps sends at 10 times the subscriber tier and limits you to 50 automations, the premium is large.
Free plans and limits
MailerLite's Free plan is real: up to 250 subscribers, 2,500 emails a month, two seats, three automations, one website and landing page, three signup forms, and community support. Its paid page says every paid plan gets the full feature set and you pay more only for a bigger list or more sending. Comfort allows 50 automations and removes the MailerLite logo; Power makes automations, landing pages and forms unlimited. Customer.io has nothing equivalent below $100, so a pre-launch list under a few thousand people is a MailerLite story unless you qualify for the Startup Program (12 months free for companies that have raised under $10M).
Billing events: selling through Stripe versus reacting to Stripe
This is the sharpest product difference for a subscription business, and it is easy to miss because both tools say "Stripe integration".
- MailerLite uses Stripe as a payment processor for its own landing pages and websites. Its Stripe page describes one-time and recurring purchase blocks, notes that recurring purchases accept cards only, and quotes Stripe's 2.9% + 30¢ per successful card charge. It lists Zapier, Make and Integrately as outside routes for sending Stripe data, such as creating a contact when an order is created (MailerLite for Stripe). It says nothing about trial-ending, past-due or cancellation triggers.
- Customer.io documents the opposite direction: your existing Stripe account sends webhooks to a webhook-triggered automation, people are matched by Stripe customer ID, and the docs name
invoice.payment_failedas a dunning use case (Customer.io Stripe tutorial).
If you already bill in Stripe, Paddle or Lemon Squeezy and just need a place to mail customers, the second pattern is the one that matches.
Other differences that move the decision
- Transactional email. Customer.io includes it on all plans. MailerLite points you to MailerSend, which has its own tab and plans, so receipts and password resets are a second vendor.
- Data hosting. MailerLite states its data storage center is in the European Union with ISO 27001, and says it has the GDPR controls. Customer.io lists US and EU data centers and a published DPA.
- Data model. Customer.io profiles hold people plus objects (two object types on Essentials, ten on Premium). MailerLite is a subscriber list with groups and segments.
- Reach beyond email. MailerLite adds landing pages, websites and digital product sales. Customer.io's page lists email, push, in-app, WhatsApp and SMS-related capacity.
Moving a list between them
- Export subscribers with groups and custom fields. On MailerLite, import unsubscribed contacts as unsubscribed so the new tool never mails them.
- Decide which of your MailerLite groups were really behavior flags. In Customer.io those become event-driven segments, not static lists.
- Send three or four product events from your app (signed up, activated, trial ended, cancelled) before rebuilding any automation.
- Set up SPF and DKIM for the same sending domain in both tools and keep the old one live for a full billing cycle.
Which to choose
- MailerLite Power if you need unlimited automations and a landing page builder for a list under 25,000 and your triggers are mostly signup and tag based.
- Customer.io Essentials if onboarding branches on in-app behavior and failed payments must trigger emails.
- MailerLite Free while the list is below 250 subscribers and you only need the basics.
Related reading: all comparisons, Customer.io vs Brevo, Mailchimp vs MailerLite, Loops vs MailerLite and the bootstrapped founder stack.
Customer.io vs MailerLite: common questions
How much cheaper is MailerLite than Customer.io?
At 10,000 contacts, MailerLite Comfort is $89 a month against $145 for Customer.io Essentials, a $56 gap or $672 over twelve months. MailerLite Power, at $129, narrows that to $16. At 1,000 subscribers the gap is widest in relative terms: Comfort is $19, while Customer.io's selector starts at 5,000 profiles for $100.
Does MailerLite have a free plan?
Yes: up to 250 subscribers and 2,500 emails a month, two user seats, three automations and a landing page, per its pricing page. Customer.io has no free plan, though companies that raised under $10M can get 12 months free through its Startup Program.
Can MailerLite react to Stripe subscription events?
Its Stripe page is about selling: you add one-time or recurring purchase blocks to landing pages and websites, recurring purchases accept cards only, and Stripe charges 2.9% + 30¢ per successful card charge. The page does not describe syncing payment events into automations, though it lists Zapier and Make as ways to connect the two. Customer.io documents a webhook-triggered route for Stripe events.
Does either tool include transactional email?
Customer.io lists transactional emails as included on every plan. MailerLite does not send transactional email in the marketing product; its pricing page has a separate Transactional tab, and the transactional product is MailerSend.