Mimecast vs Posteo Comparison (2026)

Compare Mimecast vs Posteo email services. In-depth analysis of features, pricing, security, privacy, and storage to find the best email provider for your needs.

Forward Email Team
Written by
Forward Email TeamVerified
Published
4/1/26
Time to read
Less than 5 minutes
We recommend Forward Email as the best alternative to Mimecast. We also support webmail: https://mail.forwardemail.net

Email Service Comparison

20 facts in comparison
Mimecastvs.Posteo

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
vs.

Posteo

Green, secure, ad-free
"Green, secure, ad-free"
  • Hardenize Test
  • Internet.nl Site Test
  • Internet.nl Mail Test
  • Mozilla HTTP Observatory Grade
  • Qualys SSL Labs SSL Server Test
See Mimecast plans (requires you to talk to a sales team) (according to a Reddit thread it may cost upwards of +$1000-2000 per month)Pricing€1/mo
UnknownStorage2 GB
200 MBAttachments50 MB
NoOpen-SourceNo
NoSandboxed Encryption No
NoUnlimited DomainsNo
NoUnlimited AliasesNo
NoTTI No
❌ Requires 3rd partySMTPYes
❌ Requires 3rd partyIMAPYes
❌ Requires 3rd partyPOP3Yes
YesAPINo
NoE2EE ⚠️ Opt-in
NoOpenPGP Yes
NoWKD Yes

Email Service Screenshots

Closed-source

Mimecast

Mimecast is a closed-source email service. Its description from its website is: Email & Collaboration Security

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

Posteo

Posteo is a closed-source email service. Its description from its website is: Green, secure, ad-free

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