Postmark vs Altospam Comparison (2025)

What are the differences between Postmark and Altospam?

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 Postmark.

Email Service Comparison

20 facts in comparison
Postmarkvs.Altospam

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
vs.

Altospam

Antispam, Antivirus & Anti-Phishing Software
"Antispam, Antivirus & Anti-Phishing Software"
  • Hardenize Test
  • Internet.nl Site Test
  • Internet.nl Mail Test
  • Mozilla HTTP Observatory Grade
  • Qualys SSL Labs SSL Server Test
$15/moPricingRequires you to talk to a sales team
No Postmark does not support storageStorageRequires 3rd party
10 MBAttachmentsUnknown
NoOpen-SourceNo
NoSandboxed Encryption No
NoUnlimited DomainsNo
NoUnlimited AliasesNo
TTI TTI No
YesSMTP❌ Requires 3rd party
NoIMAP❌ Requires 3rd party
NoPOP3❌ Requires 3rd party
YesAPIYes
NoE2EE No
NoOpenPGP No
NoWKD No

Email Service Screenshots

Closed-source

Postmark

Postmark is a closed-source email service. Their official description reads: The email delivery service that people actually like

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

Altospam

Altospam is a closed-source email service. Their website says: Antispam, Antivirus & Anti-Phishing Software

Altospam is a closed-source email service.
Photo by Forward Email
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Compare Postmark with 78 email services