Mailchimp vs Customer.io Comparison (2025)

What are the differences between Mailchimp 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 Mailchimp.

Email Service Comparison

20 facts in comparison
Mailchimpvs.Customer.io

Mailchimp

Turn Emails into Revenue
"Turn Emails into Revenue"
  • 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
$33/moPricing$100/mo
No Mailchimp does not support storageStorageNo Customer.io does not support storage
25 MBAttachments2 MB
NoOpen-SourceNo
NoSandboxed Encryption No
NoUnlimited DomainsNo
NoUnlimited AliasesNo
NoTTI No
❌ Requires paid add-on for Mandrill of at least $20/moSMTPYes
NoIMAPNo
NoPOP3No
YesAPIYes
NoE2EE No
NoOpenPGP No
NoWKD No

Email Service Screenshots

Closed-source

Mailchimp

Mailchimp is a closed-source email service. Their website says: Turn Emails into Revenue

Mailchimp is a closed-source email service.
Photo by Forward Email
Visit Website
Closed-source

Customer.io

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

Customer.io is a closed-source email service.
Screenshot by Forward Email
Visit Website

Compare Mailchimp with 78 email services