Customer.io vs addy.io Comparison (2025)

What are the differences between Customer.io and addy.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 Customer.io.

Email Service Comparison

20 facts in comparison
Customer.iovs.addy.io

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.

addy.io

Protect your real email address using email aliases
"Protect your real email address using email aliases"
  • Hardenize Test
  • Internet.nl Site Test
  • Internet.nl Mail Test
  • Mozilla HTTP Observatory Grade
  • Qualys SSL Labs SSL Server Test
$100/moPricing$4/mo
No Customer.io does not support storageStorageNo addy.io does not support storage
2 MBAttachments25 MB
NoOpen-SourceYes
NoSandboxed Encryption No
NoUnlimited DomainsNo
NoUnlimited AliasesYes
NoTTI No
YesSMTPNo
NoIMAPNo
NoPOP3No
YesAPINo
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.
Photograph by Forward Email
Visit Website
Open-source

addy.io

addy.io is an open-source email service. Its description from its website is: Protect your real email address using email aliases

addy.io is an open-source email service.
Screenshot by Forward Email
Visit Website

Compare Customer.io with 78 email services