Customer.io vs MailerSend

Two transactional email providers, compared on price, features and ratings, so you can pick fast.

Customer.io wins compliance and analyticsMailerSend wins price and developer experience

Updated July 2026

At a glanceCustomer.ioMailerSend
G2 rating4.44.1
Trustpilot3.24.0
Drag-and-drop editorYesYes

THE VERDICT

Customer.io wins on compliance and analytics. MailerSend wins on price and developer experience.

Customer.io and MailerSend take different pricing approaches. Customer.io rates higher with developers (4.4 vs 4.1 on G2). Pick based on volume and team, and the scorecard below breaks down where each one leads.

Which should you choose?

Pick Customer.io

✓You need behavior-triggered lifecycle messaging across email, push, and SMS
✓You want journeys driven by real-time user/event data and a unified profile
✓You're consolidating marketing automation and transactional messaging
✓You need EU data residency or HIPAA-grade compliance

Pick MailerSend

✓Teams that need EU-hosted transactional email data by default for compliance or customer-trust reasons
✓Budget-conscious developers who want a real free tier plus a cheap ($7/mo) entry-level paid plan
✓Teams that want built-in email address verification without adding a separate vendor
✓Apps that need inbound email parsing (support tickets, reply-by-email flows) alongside outbound sending
Set up MailerSend with Courier →

Feature by feature

Winner cells are tinted, green where Customer.io leads, violet where MailerSend does.

capability
Customer.io
MailerSend
Starting paid plan
$100/mo
$7/mo
Pricing model
Subscription
Hybrid
Overage
Profile-based pricing: additional profiles $0.009 each; additional emails $0.12 per 1,000 over the plan's bundled allowance; AI credits $10/100K. Email volume does not map to a per-email tier.
$1.50 per 1,000 emails beyond the plan's included allowance
Dedicated IP
Plan-gated
Plan-gated
Deliverability tooling
Yes
Yes
Automated IP warmup
Yes
Yes
Suppression management
Yes
Yes
SPF / DKIM / DMARC
Yes
Yes
Transactional API
Yes
Yes
Marketing campaigns
Yes
No
SMTP relay
Yes
Yes
Inbound routing
No
Yes
Dynamic templates
Yes
Yes
Batch send
Yes
Yes
Scheduled send
Yes
Yes
Official SDKs
Ruby, Python, Node.js, Go, PHP, JavaScript (Web), iOS, Android, React Native, Flutter, Expo
PHP, Laravel, Node.js, Go, Python, Ruby, Java
Event webhooks
Yes
Yes
Drag-and-drop editor
Yes
Yes
Custom HTML editor
Yes
Yes
Email validation
No
Yes
Log retention
—
Plan-gated: 1 day (Free/Hobby), 7 days (Starter), 30 days (Professional)
Sandbox / test mode
—
Yes
Open / click tracking
Yes
Yes
Analytics dashboard
Yes
Yes
A/B testing
Yes
Plan-gated
EU data residency
Yes
Yes
SOC 2
Yes
No
HIPAA
BAA
No
GDPR
Yes
Yes
ISO 27001
Yes
—
Support channels
Community + email (Essentials); chat (Standard); dedicated CSM + technical specialist (Premium/Enterprise)
Limited support on Free; 24/7 email support from Hobby; live chat plus priority support on Starter and Professional; dedicated account manager on Professional
24/7 support
—
Yes
Support SLA
Plan-gated
—
Migration assistance
Yes
Plan-gated

FAQ

Common questions

Customer.io rates higher on G2 (4.4 vs 4.1). Ratings are aggregated from public review platforms as of the date shown.

Keep comparing

Related comparisons

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Why not both?

Use both behind one API.

Route Customer.io, MailerSend, or both, and switch providers without changing your code. Courier sits in front of every channel.

Start building freeRead the docs

Pricing, plans and feature availability as of July 2026 and may change. Ratings are aggregated from public review platforms.

Multichannel Notifications Platform for SaaS