Mailtrap vs Customer.io Comparison (2025)

What are the differences between Mailtrap 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 Mailtrap.

Email Service Comparison

20 facts in comparison
Mailtrapvs.Customer.io

Mailtrap

Email Delivery Platform that delivers just in time. Great for businesses and individuals
"Email Delivery Platform that delivers just in time. Great for businesses and individuals"
  • 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
$10/moPricing$100/mo
No Mailtrap does not support storageStorageNo Customer.io does not support storage
10 MBAttachments2 MB
NoOpen-SourceNo
NoSandboxed Encryption No
NoUnlimited DomainsNo
NoUnlimited AliasesNo
NoTTI No
YesSMTPYes
NoIMAPNo
NoPOP3No
YesAPIYes
NoE2EE No
NoOpenPGP No
NoWKD No

Email Service Screenshots

Closed-source

Mailtrap

Mailtrap is a closed-source email service. Their official description reads: Email Delivery Platform that delivers just in time. Great for businesses and individuals

Mailtrap is a closed-source email service.
Photograph by Forward Email
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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.
Photo by Forward Email
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Compare Mailtrap with 78 email services