Heimdal vs Postmark Comparison (2025)

What are the differences between Heimdal and Postmark?

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.Postmark

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.

Postmark

The email delivery service that people actually like
"The email delivery service that people actually like"
  • 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$15/mo
Requires 3rd partyStorageNo Postmark does not support storage
UnknownAttachments10 MB
NoOpen-SourceNo
NoSandboxed Encryption No
NoUnlimited DomainsNo
NoUnlimited AliasesNo
NoTTI TTI
❌ Requires 3rd partySMTPYes
❌ Requires 3rd partyIMAPNo
❌ Requires 3rd partyPOP3No
YesAPIYes
NoE2EE No
NoOpenPGP No
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.
Screenshot by Forward Email
Go to site
Closed-source

Postmark

Postmark is a closed-source email service. Their website says: The email delivery service that people actually like

Postmark is a closed-source email service.
Screenshot by Forward Email
Go to site

Compare Heimdal with 78 email services