Aster Mail vs Proton Mail

Aster Mail is an open-source email service with a free plan and paid tiers. It supports web, desktop, and Android, with an iOS beta on TestFlight; native desktop apps are available for Windows, Mac, and Linux. Aster Bridge lets desktop mail apps connect over IMAP and SMTP. Mail between Aster accounts is automatically end-to-end encrypted and uses hybrid post-quantum encryption. The free plan costs nothing and includes 10 GB of encrypted storage, five aliases, one custom domain, two mail rules, attachments up to 25 MB per message, and Bridge access; no trial or credit card is required. Aster says its email is hosted in Germany under EU privacy law and that it does not use ads, inbox scanning, or AI on the inbox. QuickSwitch imports mail from Gmail, Outlook, Yahoo, Proton, and other IMAP providers. MBOX mailbox export is free on every plan. Paid plans start at $2.42 a month, billed annually, with the final amount determined at checkout. Aster Mail was founded in 2026 and is headquartered in Orlando, Florida, United States.

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.