Customer.io vs Mimecast Comparison (2026)

What are the differences between Customer.io and Mimecast?

Forward Email Team
Written by
Forward Email TeamVerified
Published
3/1/26
Time to read
Less than 5 minutes
We recommend Forward Email as the best alternative to Customer.io. We also support webmail: https://mail.forwardemail.net

Email Service Comparison

20 facts in comparison
Customer.iovs.Mimecast

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.

Mimecast

Email & Collaboration Security
"Email & Collaboration Security"
  • Hardenize Test
  • Internet.nl Site Test
  • Internet.nl Mail Test
  • Mozilla HTTP Observatory Grade
  • Qualys SSL Labs SSL Server Test
$100/moPricingSee Mimecast plans (requires you to talk to a sales team) (according to a Reddit thread it may cost upwards of +$1000-2000 per month)
No Customer.io does not support storageStorageUnknown
2 MBAttachments200 MB
NoOpen-SourceNo
NoSandboxed Encryption No
NoUnlimited DomainsNo
NoUnlimited AliasesNo
NoTTI No
YesSMTP❌ Requires 3rd party
NoIMAP❌ Requires 3rd party
NoPOP3❌ Requires 3rd party
YesAPIYes
NoE2EE No
NoOpenPGP No
NoWKD No

Email Service Screenshots

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.
Photograph by Forward Email
Visit Website
Closed-source

Mimecast

Mimecast is a closed-source email service. Its description from its website is: Email & Collaboration Security

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

Compare Customer.io with 78 email services