Customer.io vs ImprovMX Comparison (2026)

What are the differences between Customer.io and ImprovMX?

Forward Email Team
Written by
Forward Email TeamVerified
Published
1/1/26
Time to read
Less than 5 minutes
We recommend Forward Email as the best alternative to Customer.io.

Email Service Comparison

20 facts in comparison
Customer.iovs.ImprovMX

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
vs.

ImprovMX

Create free email aliases for your domain name
"Create free email aliases for your domain name"
  • Hardenize Test
  • Internet.nl Site Test
  • Internet.nl Mail Test
  • Mozilla HTTP Observatory Grade
  • Qualys SSL Labs SSL Server Test
$100/moPricing$9/mo
No Customer.io does not support storageStorageNo ImprovMX does not support storage
2 MBAttachments50 MB
NoOpen-SourceNo
NoSandboxed Encryption No
NoUnlimited DomainsNo
NoUnlimited AliasesNo
NoTTI TTI
YesSMTPYes
NoIMAPNo
NoPOP3No
YesAPIYes
NoE2EE No
NoOpenPGP No
NoWKD No

Email Service Screenshots

Closed-source

Customer.io

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

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

ImprovMX

ImprovMX is a closed-source email service. Their official description reads: Create free email aliases for your domain name

ImprovMX is a closed-source email service.
Photograph by Forward Email
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Compare Customer.io with 78 email services