4SecureMail vs Proton Mail

4SecureMail provides secure email accounts and managed email hosting for businesses and consumers. Accounts support POP, IMAP, and SMTP with SSL/TLS and work with standard clients such as Outlook and Thunderbird. SecureVault encrypts sensitive outgoing email for outside recipients, who read and reply through a secure web link. Spam protection includes SpamAssassin and a challenge/response whitelist; a server-based ICSA-certified virus scanner is also included. The FAQ says SSL/TLS sessions begin before login credentials are exchanged, and that TLS 1.2 and Perfect Forward Secrecy are supported. The company describes support for HIPAA, GLB, and SOX, can provide or review a Business Associate Agreement, and offers off-site legal archiving at additional cost. IMAP IDLE notifications and simultaneous connections from multiple devices are supported. Outgoing attachments can total up to 5 GB across all recipients. Plans range from one mailbox with 500 MB of storage and no custom domain to options with multiple mailboxes, more storage, and custom domains. The service has no free plan but offers a free trial; listed pricing starts at $8.24/mo. It is available worldwide to holders of major credit cards and supports U.S. currency.

Proton Mail is an encrypted email service available on the web, Windows, macOS, Linux, iOS, and Android. Its free plan lists 1 GB of storage and one email address, although its FAQ says storage starts at 500 MB; the free tier is described as having the same security level as paid plans. The service uses end-to-end and zero-access encryption, with open-source apps and independent audits. It blocks email trackers and includes phishing and spam protection, password-protected messages, and link confirmation. Users can schedule, undo, or snooze emails and organize messages with folders, labels, and categories. Easy Switch imports email, calendars, and contacts from other providers. Paid plans support external email clients through IMAP and SMTP using Proton Mail Bridge. Mail Plus lists 15 GB of storage, 10 extra email addresses, and one custom domain. Paid subscriptions include a 30-day money-back guarantee, and the desktop app has a 14-day free trial. Paid plans display monthly billing; the listed starting price is 3.99 /user/mo.