Heimdal vs Mimecast Comparison (2025)

What are the differences between Heimdal and Mimecast?

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.Mimecast

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.

Mimecast

Email & Collaboration Security
"Email & Collaboration Security"
  • 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 teamPricingSee Mimecast plans (requires you to talk to a sales team) (according to a Reddit thread it may cost upwards of +$1000-2000 per month)
Requires 3rd partyStorageUnknown
UnknownAttachments200 MB
NoOpen-SourceNo
NoSandboxed Encryption No
NoUnlimited DomainsNo
NoUnlimited AliasesNo
NoTTI No
❌ Requires 3rd partySMTP❌ Requires 3rd party
❌ Requires 3rd partyIMAP❌ Requires 3rd party
❌ Requires 3rd partyPOP3❌ Requires 3rd party
YesAPIYes
NoE2EE No
NoOpenPGP No
NoWKD No

Email Service Screenshots

Closed-source

Heimdal

Heimdal is a closed-source email service. Their official description reads: One Platform. Total Security.

Heimdal is a closed-source email service.
Photograph by Forward Email
Go to site
Closed-source

Mimecast

Mimecast is a closed-source email service. Their official description reads: Email & Collaboration Security

Mimecast is a closed-source email service.
Photograph by Forward Email
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Compare Heimdal with 78 email services