Klaviyo vs Customer.io Comparison (2025)

What are the differences between Klaviyo and Customer.io?

Forward Email Team
Written by
Forward Email TeamVerified
Published
7/1/25
Time to read
Less than 5 minutes
We recommend Forward Email as the best alternative to Klaviyo.

Email Service Comparison

20 facts in comparison
Klaviyovs.Customer.io

Klaviyo

Power smarter digital relationships
"Power smarter digital relationships"
  • Hardenize Test
  • Internet.nl Site Test
  • Internet.nl Mail Test
  • Mozilla HTTP Observatory Grade
  • Qualys SSL Labs SSL Server Test
vs.

Customer.io

Send messages people actually want to receive using real-time customer data
"Send messages people actually want to receive using real-time customer data"
  • Hardenize Test
  • Internet.nl Site Test
  • Internet.nl Mail Test
  • Mozilla HTTP Observatory Grade
  • Qualys SSL Labs SSL Server Test
$20/moPricing$100/mo
No Klaviyo does not support storageStorageNo Customer.io does not support storage
0 MBAttachments2 MB
NoOpen-SourceNo
NoSandboxed Encryption No
NoUnlimited DomainsNo
NoUnlimited AliasesNo
NoTTI No
NoSMTPYes
NoIMAPNo
NoPOP3No
NoAPIYes
NoE2EE No
NoOpenPGP No
NoWKD No

Email Service Screenshots

Closed-source

Klaviyo

Klaviyo is a closed-source email service. Their official description reads: Power smarter digital relationships

Klaviyo is a closed-source email service.
Screenshot by Forward Email
Visit Website
Closed-source

Customer.io

Customer.io is a closed-source email service. Their website says: Send messages people actually want to receive using real-time customer data

Customer.io is a closed-source email service.
Photograph by Forward Email
Go to site

Compare Klaviyo with 78 email services