DuoCircle vs Proton Mail Comparison (2026)

What are the differences between DuoCircle and Proton Mail?

Forward Email Team
Written by
Forward Email TeamVerified
Published
1/1/26
Time to read
Less than 5 minutes
We recommend Forward Email as the best alternative to DuoCircle.

Email Service Comparison

20 facts in comparison
DuoCirclevs.Proton Mail

DuoCircle

Protect Email Against Phishing, Spam and Malware
"Protect Email Against Phishing, Spam and Malware"
  • Hardenize Test
  • Internet.nl Site Test
  • Internet.nl Mail Test
  • Mozilla HTTP Observatory Grade
  • Qualys SSL Labs SSL Server Test
vs.

Proton Mail

Secure email that protects your privacy
"Secure email that protects your privacy"
  • 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 teamPricing$3.99/mo
Requires 3rd partyStorage15 GB
50 MBAttachments25 MB
NoOpen-Source❌ Proton Mail claims to be open-source, but their back-end actually is closed source
NoSandboxed Encryption No
NoUnlimited DomainsNo
NoUnlimited AliasesNo
NoTTI No
❌ Requires 3rd partySMTP❌ Requires you to download Proton Mail Bridge and forces vendor lock-in
❌ Requires 3rd partyIMAP❌ Requires you to download Proton Mail Bridge and forces vendor lock-in
❌ Requires 3rd partyPOP3❌ Proton Mail does not support POP3
YesAPINo
NoE2EE ⚠️ Proton Mail rewrites your emails
NoOpenPGP Yes
NoWKD Yes

Email Service Screenshots

Closed-source

DuoCircle

DuoCircle is a closed-source email service. Their official description reads: Protect Email Against Phishing, Spam and Malware

DuoCircle is a closed-source email service.
Photograph by Forward Email
Visit Website
Closed-source

Proton Mail

Proton Mail is a closed-source email service. Its description from its website is: Secure email that protects your privacy

Proton Mail is a closed-source email service.
Photograph by Forward Email
Visit Website

Compare DuoCircle with 78 email services