Customer.io vs Mailgun: Side-by-Side Comparison (2025)

Choosing between Customer.io and Mailgun comes down to your specific use case. Customer.io is built for product and growth teams sending behaviour-triggered messages, while Mailgun targets developers sending transactional and bulk email via API.

Quick Verdict

Overall winner
Customer.io
Better pricing
Mailgun
More features
Customer.io
For beginners
Mailgun
E-commerce
Customer.io

Feature Comparison

Feature Customer.io Mailgun
๐Ÿ’ฐ Pricing
Free Planโœ—โœ“
Starting Price$100/mo$15/mo
Free Trialโœ“โœ“
โš™๏ธ Features
Email Automationโœ“โœ—
Visual Workflow Builderโœ“โœ—
Landing Pagesโœ—โœ—
Built-in CRMโœ—โœ—
SMS Marketingโœ“โœ—
A/B Testingโœ—โœ—
E-commerce Integrationโœ—โœ—
Transactional Emailโœ“โœ“
Remove Brandingโœ“โœ—
๐Ÿค– AI Features
AI Subject Linesโœ—โœ—
AI Send-Time Optimisationโœ—โœ—
๐Ÿ›Ž Support
Email Supportโœ“โœ“
Live Chatโœ“โœ—
Phone Supportโœ“โœ—
Customer.io
โ˜…โ˜…โ˜…โ˜…โ˜† 4.4/5
Mailgun
โ˜…โ˜…โ˜…โ˜…โ˜† 4.3/5
Our verdict

Customer.io is best for product and growth teams sending behavior-triggered messages.

Try Customer.io Free โ†’
Our verdict

Mailgun is best for developers sending transactional and bulk email via API.

Try Mailgun Free โ†’

Which Should You Choose?

Choose Customer.io ifโ€ฆ

  • You are primarily focused on product and growth teams sending behaviour-triggered messages
  • You value behavioural triggers
  • You prefer paid pricing
Try Customer.io โ†’

Choose Mailgun ifโ€ฆ

  • You are primarily focused on developers sending transactional and bulk email via API
  • You value email api
  • You prefer freemium pricing
Try Mailgun โ†’

Frequently Asked Questions

Is Customer.io better than Mailgun?

It depends on your use case. Customer.io wins for product and growth teams sending behaviour-triggered messages, while Mailgun is stronger for developers sending transactional and bulk email via API.

Which is cheaper, Customer.io or Mailgun?

Mailgun starts at a lower price point. Pricing scales with subscriber count so total cost depends on your list size.

Can I switch from Mailgun to Customer.io?

Yes, switching is possible. Most platforms support CSV import/export. Plan time to recreate automations and templates.