Customer.io vs Knock pricing

Name: Customer.io (Email APIs)
Brand: Customer.io
Price: 100 USD

Verified 2026-10-24 (1 day ago)Source: Customer.io: customer.io/pricing, Knock: knock.app/pricingVerified shows the older of the two.

Monthly cost at three volumes

These services do not bill on a shared metric, so a like-for-like cost is unlisted.

Tiers of Customer.io and Knock aligned by position: free, entry, mid, top
Position	Customer.io	Knock
Free	no tier	$0 / moFree · 10,000 messages sent (any channel) / mo
Entry	$100 / moEssentials · 1,000,000 emails sent / mo	$250 / moStarter · 50,000 messages sent (any channel) / mo
Mid	$1,000 / moPremium	no tier
Top	Contact salesEnterprise	Contact salesEnterprise

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

No changes recorded.

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