Proton Mail

Tracking pixel blocking and IP address hiding in the web app

Machine-learning detection of attacks targeting accounts

Custom filters (1 on Free, unlimited on Mail Plus and Proton Unlimited)

Automatic sorting of incoming mail into inbox categories

End-to-end encryption between Proton Mail users

Password-protected emails to recipients on other providers

PhishGuard flags potentially spoofed Proton Mail sender addresses in the inbox

Link protection shows the full URL and asks for confirmation before opening a link on web, iOS and Android

Email attachments encrypted end-to-end between Proton Mail users and via password-protected emails

Stored attachments protected with zero-access encryption

Two-factor authentication on all Proton accounts

Hardware security keys (YubiKey and other U2F/FIDO2 keys)

Zero-access encryption of stored messages, including mail from other providers

Own server hardware in Switzerland with fully encrypted disks

One-time passcodes from an authenticator app

Hardware security keys via U2F/FIDO2

Encryption keys managed by Proton behind the scenes

Key Transparency checks of contacts' public keys

Proton Pass included in every plan: unlimited logins, notes, credit cards and devices

2 vaults on Free and Mail Plus, 50 vaults on Proton Unlimited

Sign-in protected by 2FA with authenticator app or security key

Proton Sentinel 24/7 account monitoring on Proton Unlimited