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Tuta Desktop vs Aster Mail: catalog facts
Tuta Desktop	Aster Mail
Freemium A free account with limited storage and one address. Paid plans add custom domains…	Freemium Free plan with 10 GB of storage; paid plans start at $2.99 per month.
Windows, macOS, Linux	Android
End-to-end encrypts mail bodies, subject lines, calendar and contacts Password-protected messages to recipients who are not Tuta users	Mail is encrypted on the device before it leaves 10 GB free with custom domain support
No IMAP or SMTP, so third-party mail clients cannot be used A Tuta account is required; it is not a general mail client	The app only works with astermail.org accounts Young project with a small user base compared with established providers
Downloadable app	Downloadable app, Hosted service
Open source	Open source
License: GPL-3.0	License: AGPL-3.0
Account needed	Account needed
Needs internet	Not stated if it works offline
Official website Full listing and sources Checked September 21, 2026	Official website Full listing and sources Checked October 2, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.