N‑able Mail Assure vs Startmail Comparison (2026)

What are the differences between N‑able Mail Assure and Startmail?

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 N‑able Mail Assure. We also support webmail: https://mail.forwardemail.net

Email Service Comparison

20 facts in comparison
N‑able Mail Assurevs.Startmail

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.

Startmail

Private email you can trust
"Private email you can trust"
  • 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$7/mo
Requires 3rd partyStorage20 GB
Depends on inbound/outbound (e.g. 10 MB)Attachments25 MB
NoOpen-SourceNo
NoSandboxed Encryption ❌ Startmail claims to use a User Vault, but this statement has not been audited and their source code is closed-source
NoUnlimited DomainsNo
NoUnlimited AliasesNo
NoTTI No
❌ Requires 3rd partySMTPYes
❌ Requires 3rd partyIMAPYes
❌ Requires 3rd partyPOP3Yes
YesAPINo
NoE2EE ⚠️ Supported if both sender and recipient are using OpenPGP
NoOpenPGP ⚠️ Supports OpenPGP, but does not support WKD
NoWKD No

Email Service Screenshots

Closed-source

N‑able Mail Assure

N‑able Mail Assure is a closed-source email service. Their website says: Email protection to help you secure and scale

N‑able Mail Assure is a closed-source email service.
Photo by Forward Email
Visit Website
Closed-source

Startmail

Startmail is a closed-source email service. Their official description reads: Private email you can trust

Startmail is a closed-source email service.
Screenshot by Forward Email
Visit Website

Compare N‑able Mail Assure with 78 email services