Customer.io vs Postmark pricing

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

Monthly cost at three volumes

Monthly cost of Customer.io and Postmark at three volumes and at your own
Volume	Customer.io	Postmark
small5K emails sent	$100 / moEssentials	$15 / moBasic
growing50K emails sent	$100 / moEssentials	$66 / moPlatform
scale500K emails sent	$100 / moEssentials	$606 / moPlatform
your volumeset above	$100 / moEssentials	$66 / moPlatform

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 Postmark aligned by position: free, entry, mid, top
Position	Customer.io	Postmark
Free	no tier	$0 / moFree · 100 emails sent / mo
Entry	$100 / moEssentials · 1,000,000 emails sent / mo	$15 / moBasic · 10,000 emails sent / mo
Mid	$1,000 / moPremium	$16.50 / moPro · 10,000 emails sent / mo
Top	Contact salesEnterprise	$18 / moPlatform · 10,000 emails sent / mo

Tightest rate limit

Tightest documented rate limit of each service
Measure	Customer.io	Postmark
Tightest limit	unlisted	unlisted

Changes in the last 90 days

No changes recorded.

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