Aster Mail

Overview

Aster Mail is an open-source email service with encrypted mail, custom domains and access from web, mobile and desktop. It is best suited to people who want room to grow from a usable free mailbox into larger storage and domain allowances. Its automatic encryption is a clear draw for mail between Aster accounts, though it does not extend that stated protection to every recipient.

Key features

Encryption and privacy

Mail exchanged between Aster accounts is encrypted end-to-end by default, with hybrid post-quantum encryption. That makes Aster appealing for conversations within its user base, but readers should not assume the same end-to-end protection for messages sent elsewhere. 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. There is no encrypted calendar.

Desktop access, migration and export

Native apps cover Windows, Mac and Linux, while the service also supports web and Android; its iOS app is in TestFlight beta. Aster Bridge supports IMAP and SMTP mail apps, giving desktop users another way to work with their mailbox. QuickSwitch imports from Gmail, Outlook, Yahoo, Proton and other IMAP providers, and one-click MBOX export is free on every plan. That combination lowers the friction of switching in and preserves an exit route.

Pricing

The free plan costs nothing, forever, with no credit card required. It includes 10 GB encrypted storage, five aliases, one custom domain, end-to-end encryption and Bridge access. The free tier also permits two mail rules and attachments up to 25 MB per message. With no trial requirement, it is a substantial starting point, although the storage, alias and rule caps may constrain a busier mailbox.

Star costs $2.42 a month (billed annually), with a stated 19% saving and final amount determined at checkout. Its 50 GB, 15 aliases, five custom domains and unlimited mail rules make it the modest paid step for users who outgrow Free. Nova costs $7.25 a month (billed annually), also with a stated 19% saving and final amount determined at checkout; 500 GB, unlimited aliases, 30 domains and unlimited rules suit heavier or multi-domain use. Supernova costs $14.50 a month (billed annually), with the final amount determined at checkout. It raises storage to 5 TB and allows unlimited aliases and domains and unlimited rules, adding dedicated support for users who need the largest allowance.

All three paid plans include Bridge access. The first paid plan has a 30-day money-back guarantee; renewals are excluded. Check the checkout total against the annual term before committing.

Platforms

Aster supports web, Android, and desktop apps for Windows, Mac and Linux. iOS access is through a TestFlight beta, so readers who need a stable iOS release should weigh that limitation. Bridge adds desktop IMAP and SMTP compatibility.

Who it's for

Aster is a good fit for people who want account-to-account encryption, a free custom domain and desktop-client flexibility, especially if they may need to import an existing mailbox or export it later. It is less compelling for users who require an encrypted calendar or depend on a finished iOS app.

Pros and cons

• Pro: The free tier combines 10 GB, five aliases and one custom domain without a card or trial.
• Pro: Bridge, migration from major providers and free MBOX export make desktop use and switching more practical.
• Pro: Paid tiers scale to 5 TB and unlimited aliases and domains.
• Con: Automatic end-to-end encryption is stated for mail between Aster accounts, not universally.
• Con: There is no encrypted calendar, and iOS remains in beta on TestFlight.
• Con: Paid prices are annual-billing rates with the final checkout amount determined at checkout.

Alternatives

Proton Mail is worth considering for readers comparing another free encrypted-mail service with web, desktop and mobile platforms. Tuta Mail is another freemium option with end-to-end encryption and apps across desktop and mobile. eclipso Mail Europe offers a free plan with 4 GB storage and one address if a smaller free mailbox is enough. Disroot Email supports IMAP, SMTP, SMTPS and POP, with optional PGP encryption through Mailvelope. Private-Mail pairs encrypted email storage with encrypted cloud storage and SecureShare. mail.de offers a free option with 500 MB storage and a 60 MB attachment limit. Mailfence has a free plan with 500 MB email storage and 500 MB document storage. Mailo combines a free mailbox with document and photo storage and IMAP4 and EAS access. For broader comparisons, see Secure Email Providers, Private Email Services and Email providers.

Verdict

Choose Aster Mail if you want account-to-account encrypted email, desktop-client support and a free plan with a custom domain, plus clear paths to migration and export. Look elsewhere if you need an encrypted calendar, a stable iOS app or encryption assured for mail beyond Aster accounts.