Two transactional email providers, compared on price, features and ratings, so you can pick fast.
Customer.io wins automation and multichannelResend wins developer experience and pricing
Updated August 2026
At a glanceCustomer.ioResend
Cost per 1k @ 100k—$0.35
G2 rating4.44.8
Drag-and-drop editorYesYes
THE VERDICT
Customer.io wins on automation and multichannel. Resend wins on developer experience and pricing.
These two solve different problems. Resend is a developer-first email API, a clean, modern API, React Email templating, nine SDKs, and a generous free tier (3,000 emails/month) from $20/mo, built to add transactional and light marketing email to an app fast. Customer.io is a full customer-engagement platform: visual journeys, behavioral segmentation, and multichannel messaging (email, push, SMS, in-app) driven by product data. Pick Resend to ship email from code; pick Customer.io when you need marketing automation and cross-channel journeys, not just an email API.
Which should you choose?
Pick Customer.io
✓Visual journey builder and behavioral segmentation
✓Multichannel: email, push, SMS, and in-app
✓Campaigns driven by product/behavioral data
Pick Resend
✓Clean, modern API with React Email templating
✓Generous free tier (3,000/mo) and low $20/mo entry
Winner cells are tinted, green where Customer.io leads, violet where Resend does.
capability
Customer.io
Resend
Pricing
Starting paid plan
$100/mo
$20/mo
Cost per 1k @ 100k
—
$0.35
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.
$0.90 per 1,000 emails beyond included volume (lower on higher Scale tiers, down to ~$0.46/1k)
Email/ticket support; dedicated Slack channel and direct engineer access on Enterprise
Support SLA
Plan-gated
Plan-gated
Migration assistance
Yes
—
FAQ
Common questions
Resend is the developer-first choice, a minimal, modern email API with React Email and nine SDKs. Customer.io is a broader marketing-engagement platform; its value is journeys and segmentation rather than a lightweight sending API.