Aster Mail vs Posteo
Aster Mail
astermail.org
Posteo
posteo.deSide by side
| Figure | Aster Mail | Posteo |
|---|---|---|
| Price from | $2.42/mo | — |
| Free plan | Yes | — |
| Free trial | — | — |
| Open source | Yes | — |
| Web | Yes | Yes |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | — |
| iOS | Yes | Yes |
| Android | Yes | Yes |
| Plans published | 4 | 2 |
| Spec score · Private Email Services | 9.5 (#1) | 7.7 (#22) |
| Spec score · Secure Email Providers | 9.5 (#1) | 7.6 (#23) |
| Spec score · Email providers | 9.4 (#2) | 7.3 (#26) |
| Email encryption | Mail between Aster accounts is end-to-end encrypted automatically. | The page describes encrypted email storage and integrated PGP support. |
| End-to-end encryption | Yes | Yes |
| Headquarters | Orlando, Florida, United States | Berlin, Germany |
| Mailbox storage | 50 | 4 |
Plans
In their own words
Aster 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.