N‑able Mail Assure vs Customer.io Comparison (2025)

What are the differences between N‑able Mail Assure 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 N‑able Mail Assure.

Email Service Comparison

20 facts in comparison
N‑able Mail Assurevs.Customer.io

N‑able Mail Assure

Email protection to help you secure and scale
"Email protection to help you secure and scale"
  • 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
Requires you to talk to a sales teamPricing$100/mo
Requires 3rd partyStorageNo Customer.io does not support storage
Depends on inbound/outbound (e.g. 10 MB)Attachments2 MB
NoOpen-SourceNo
NoSandboxed Encryption No
NoUnlimited DomainsNo
NoUnlimited AliasesNo
NoTTI No
❌ Requires 3rd partySMTPYes
❌ Requires 3rd partyIMAPNo
❌ Requires 3rd partyPOP3No
YesAPIYes
NoE2EE No
NoOpenPGP No
NoWKD No

Email Service Screenshots

Closed-source

N‑able Mail Assure

N‑able Mail Assure is a closed-source email service. Its description from its website is: Email protection to help you secure and scale

N‑able Mail Assure is a closed-source email service.
Photo by Forward Email
Go to site
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.
Screenshot by Forward Email
Visit Website

Compare N‑able Mail Assure with 78 email services