Aster Mail vs Tau 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.

Tau Mail is an email service with webmail and native Android and iOS apps. It says messages are encrypted on the device before leaving, with only the sender and recipient holding keys, and advertises zero tracking rather than inbox scanning for advertising profiles. On-device spam detection and priority sorting are described as working without uploading message content. Users can bring their own domain with full DNS control. Webmail uses the same login as the mobile apps and needs no installation. Mobile apps include inbox synchronization, calendar, and contacts. The service offers a free plan with 1 GB encrypted storage and one custom alias. Pro costs $8 a month and includes 50 GB encrypted storage, five custom domains, priority routing, and advanced filters. Business costs $16 a month with unlimited storage, a team admin console, audit trail exports, and dedicated support. Tau Mail is identified as a Tau Technology Group service.