Heimdal vs Startmail Comparison (2025)

What are the differences between Heimdal and Startmail?

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 Heimdal.

Email Service Comparison

20 facts in comparison
Heimdalvs.Startmail

Heimdal

One Platform. Total Security.
"One Platform. Total Security."
  • 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
UnknownAttachments25 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

Heimdal

Heimdal is a closed-source email service. Its description from its website is: One Platform. Total Security.

Heimdal is a closed-source email service.
Photo by Forward Email
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Closed-source

Startmail

Startmail is a closed-source email service. Its description from its website is: Private email you can trust

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

Compare Heimdal with 78 email services