Customer.io vs Resend pricing

Verified 2026-10-23 (2 days ago)Source: Customer.io: customer.io/pricing, Resend: resend.com/pricingVerified shows the older of the two.

Monthly cost at three volumes

Monthly cost of Customer.io and Resend at three volumes and at your own
Volume	Customer.io	Resend
small5K emails sent	$100 / moEssentials	$20 / moPro
growing50K emails sent	$100 / moEssentials	$20 / moPro
scale500K emails sent	$100 / moEssentials	$425 / moPro
your volumeset above	$100 / moEssentials	$20 / moPro

Each cell is the cheapest feasible plan, or the chosen model, at that volume, from the shared Overage cost function. "Cheapest model" only considers models with both an input and an output price listed. Volumes are example scenarios you can edit.

Tiers, aligned by position

Tiers of Customer.io and Resend aligned by position: free, entry, mid, top
Position	Customer.io	Resend
Free	no tier	$0 / moFree · 3,000 emails sent / mo
Entry	$100 / moEssentials · 1,000,000 emails sent / mo	$20 / moPro · 50,000 emails sent / mo
Mid	$1,000 / moPremium	$90 / moScale · 100,000 emails sent / mo
Top	Contact salesEnterprise	Contact salesCustom

Tightest rate limit

Tightest documented rate limit of each service
Measure	Customer.io	Resend
Tightest limit	unlisted	100 emails sent per dayFree tier

Changes in the last 90 days

No changes recorded.

No change detected for either service in the last 90 days.