Startmail vs ImprovMX Comparison (2025)

What are the differences between Startmail and ImprovMX?

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 Startmail.

Email Service Comparison

20 facts in comparison
Startmailvs.ImprovMX

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
vs.

ImprovMX

Create free email aliases for your domain name
"Create free email aliases for your domain name"
  • Hardenize Test
  • Internet.nl Site Test
  • Internet.nl Mail Test
  • Mozilla HTTP Observatory Grade
  • Qualys SSL Labs SSL Server Test
$7/moPricing$9/mo
20 GBStorageNo ImprovMX does not support storage
25 MBAttachments50 MB
NoOpen-SourceNo
❌ Startmail claims to use a User Vault, but this statement has not been audited and their source code is closed-sourceSandboxed Encryption No
NoUnlimited DomainsNo
NoUnlimited AliasesNo
NoTTI TTI
YesSMTPYes
YesIMAPNo
YesPOP3No
NoAPIYes
⚠️ Supported if both sender and recipient are using OpenPGPE2EE No
⚠️ Supports OpenPGP, but does not support WKDOpenPGP No
NoWKD No

Email Service Screenshots

Closed-source

Startmail

Startmail is a closed-source email service. Their official description reads: Private email you can trust

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

ImprovMX

ImprovMX is a closed-source email service. Its description from its website is: Create free email aliases for your domain name

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