Postmark vs Fastmail Comparison (2025)

What are the differences between Postmark and Fastmail?

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.Fastmail

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.

Fastmail

Fast, private email that’s just for you
"Fast, private email that’s just for you"
  • Hardenize Test
  • Internet.nl Site Test
  • Internet.nl Mail Test
  • Mozilla HTTP Observatory Grade
  • Qualys SSL Labs SSL Server Test
$15/moPricing$3/mo
No Postmark does not support storageStorage2 GB
10 MBAttachments70 MB
NoOpen-SourceNo
NoSandboxed Encryption No
NoUnlimited DomainsNo
NoUnlimited AliasesNo
TTI TTI No
YesSMTPYes
NoIMAPYes
NoPOP3Yes
YesAPINo
NoE2EE No
NoOpenPGP ⚠️ Fastmail does support PGP, but not in their webmail; see this blog post for insight
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.
Photograph by Forward Email
Go to site
Closed-source

Fastmail

Fastmail is a closed-source email service. Their official description reads: Fast, private email that’s just for you

Fastmail is a closed-source email service.
Photo by Forward Email
Go to site

Compare Postmark with 78 email services