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Head-to-head · Secure Email Providers

Proton Mail vs Aster Mail

  • Updated Oct 2026
  • Both researched from official sources
  • 6 checks side by side
Higher score Proton Mail #1 in Secure Email Providers 9.4/10 Free plan Free plan✓ 3 of 3 features Visit Proton Mail
Aster Mail #3 in Secure Email Providers 8.9/10 Free plan Free plan✓ 2 of 3 features Visit Aster Mail

Proton Mail leads on 1 check, Aster Mail on 2, and 3 are even. Who comes out ahead on the 6 yes/no, price and count checks where we have data for both products. The editor score weighs everything else too.

Our verdict

  • Highest scoreProton Mail · 9.4/10
  • Free planboth
  • Most featuresProton Mail · 3 of 3

Proton Mail scores higher on our rubric for secure email providers: 9.4 against 8.9 out of 10; our editors rank them #1 and #3.

Aster Mail leads on mailbox storage: 50 GB versus 15 GB. Aster Mail leads on email aliases: 15 aliases versus 10 aliases. Proton Mail offers encrypted calendar; Aster Mail doesn't.

Proton Mail is the better fit for most users seeking a complete secure email suite. Aster Mail is the better fit for feature-rich secure email at a low price.

  • Proton Mail fits best

    Most users seeking a complete secure email suite

  • Aster Mail fits best

    Feature-rich secure email at a low price

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Side by side

Feature Proton Mail 9.4/10 Visit ↗ Aster Mail 8.9/10 Visit ↗
At a glance
Editor score 9.4 8.9
Ranking #1 in Secure Email Providers #3 in Secure Email Providers
Best for Most users seeking a complete secure email suite Feature-rich secure email at a low price
Pricing model Free plan + paid Free plan + paid
Starting price — $2.42/user/mo
Free plan ✓ ✓
Free trial — —
Deployment Cloud, Desktop, Mobile Cloud, Desktop, Mobile
Platforms Web, Windows, macOS, Linux, iOS, Android Web, Windows, macOS, Linux, iOS, Android
Integrations 5 integrations 6 integrations
Features Proton Mail 3/3 · Aster Mail 2/3
End-to-end encryption ✓ ✓
Custom domain ✓ ✓
Encrypted calendar ✓ (best) —
Specs
Mailbox storage 15 GB 50 GB (best)
Email aliases 10 aliases 15 aliases (best)
Mail protocol support Bridge Bridge
Our review
Pros
  • End-to-end encryption and zero-access storage protect messages and attachments
  • Free plan includes 1 GB storage and 1 encrypted email address
  • Bridge connects desktop clients including Outlook, Thunderbird, and Apple Mail
  • Free plan includes 10 GB encrypted storage and five aliases
  • OpenPGP, tracker blocking, import, export, and mail rules
  • Web, desktop, and mobile apps plus Aster Bridge support
Cons
  • Custom domains and expanded storage require a paid plan
  • Some desktop-client features depend on Proton Mail Bridge
  • Advanced plans may offer more capacity than light email users need
  • Encrypted calendar is still in active development
  • Server code is not public, despite open-source apps and cryptography
  • Founded in 2026, so long-term maturity evidence is limited
Our verdict

Proton Mail is an encrypted email service for individuals, organizations, journalists, activists, and businesses. It combines end-to-end encryption for messages between Proton Mail users with zero-access encryption for stored messages and…

Read the review →

Aster Mail is an encrypted email service for privacy-conscious individuals, families, and teams. Its core design combines local encryption on supported devices with a zero-access encrypted mailbox architecture. Users can access mail…

Read the review →
  1. Proton MailSecure Email Providers 9.4Free plan
  2. Aster MailSecure Email Providers 8.9Free plan

Strengths and trade-offs

  • Proton Mail — where it wins

    • End-to-end encryption and zero-access storage protect messages and attachments
    • Free plan includes 1 GB storage and 1 encrypted email address
    • Bridge connects desktop clients including Outlook, Thunderbird, and Apple Mail

    Where it doesn't

    • Custom domains and expanded storage require a paid plan
    • Some desktop-client features depend on Proton Mail Bridge
    • Advanced plans may offer more capacity than light email users need

  • Aster Mail — where it wins

    • Free plan includes 10 GB encrypted storage and five aliases
    • OpenPGP, tracker blocking, import, export, and mail rules
    • Web, desktop, and mobile apps plus Aster Bridge support

    Where it doesn't

    • Encrypted calendar is still in active development
    • Server code is not public, despite open-source apps and cryptography
    • Founded in 2026, so long-term maturity evidence is limited

More comparisons

All secure email providers comparisons → · Full ranking →

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Last updated · How we research and update