Customer.io vs Spam Scanner Comparison (2026)

What are the differences between Customer.io and Spam Scanner?

Forward Email Team
Written by
Forward Email TeamVerified
Published
2/1/26
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.Spam Scanner

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.

Spam Scanner

Spam Scanner is the best anti-spam, email filtering, and phishing prevention service
"Spam Scanner is the best anti-spam, email filtering, and phishing prevention service"
  • Hardenize Test
  • Internet.nl Site Test
  • Internet.nl Mail Test
  • Mozilla HTTP Observatory Grade
  • Qualys SSL Labs SSL Server Test
$100/moPricingFree (built-in to Forward Email)
No Customer.io does not support storageStorageRequires 3rd party
2 MBAttachmentsUnknown
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 website says: Send messages people actually want to receive using real-time customer data

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

Spam Scanner

Spam Scanner is a closed-source email service. Their website says: Spam Scanner is the best anti-spam, email filtering, and phishing prevention service

Spam Scanner is a closed-source email service.
Photo by Forward Email
Go to site

Compare Customer.io with 78 email services