Inside Aster Mail
1 / 1Aster Mail inbox — official publisher image showing folders, labels and message categories.
A free hosted mailbox with open-source clients
Aster Mail is an email service with open-source clients for Windows, macOS, Linux and the web. You create an Aster account to use its hosted mailbox. The ongoing Free plan includes 10 GB of storage, one custom domain and five email aliases, with no payment card required. Domain registration is separate.
What the free account includes
- A hosted mailbox with aliases and support for a domain you own.
- Folders, labels, search and contacts for organising mail.
- Blocking for tracking pixels and remote images.
- Access through the browser or the official desktop apps.
Higher plans expand storage and account limits. Aster Bridge, which connects the account to mail programs such as Thunderbird, Apple Mail and Outlook through local IMAP and SMTP, requires the paid Star plan or above. It is not part of the free account.
Understand the encryption boundary
Aster says mail between Aster accounts is encrypted on the device, including subjects and attachments, and uses its post-quantum scheme. Mail exchanged with another provider has different protection: compatible recipients can use OpenPGP, while incoming mail without OpenPGP reaches Aster's servers readable before being encrypted for storage. Sender and recipient addresses and timestamps remain visible for delivery. The service therefore should not be described as end-to-end encrypted for every possible email exchange.
The client is published under AGPL-3.0-only. The hosted backend is proprietary, so the open-source client licence does not make the complete hosted service open source. This listing reports the publisher's documented design; we have not audited its cryptography.
Choose a supported client
The Windows download reviewed here is the x64 installer for version 1.4.80, released on 5 November 2026. The publisher specifies Windows 10 or later. Its release also supplies a universal macOS package and Linux packages for x86-64 and ARM64. A current browser can access the web app without a desktop installation. An internet connection and an Aster account are required to use the service.
- Best for
- People who want a free hosted mailbox with aliases, their own domain and open-source clients.
- Good to know
- Free: 10 GB, one domain, five aliases. Bridge requires Star or higher. The backend is proprietary; external mail is not always end-to-end encrypted.
Windows download, licence and matching source
Download the unmodified Windows x64 installer for Aster Mail 1.4.80. Its client code is licensed under AGPL-3.0-only. Download the matching 1.4.80 source archive, read the 1.4.80 licence and follow the tagged build instructions. The source manifest identifies the shared aster-ui 0.2.2 dependency.
The file is aster-1.4.80-x64.exe (14,185,925 bytes), taken from the official 1.4.80 release. SHA-256: 9d7a990d0906d0131ea14c2ecb034d4638a9de43b931e7d466199a49592cab9b.
The exact-file VirusTotal report returned 0 malicious and 0 suspicious findings, with 70 engines reporting undetected, one timing out and four not supporting the file. These results are not a safety guarantee. The installer was not executed during our review.
Official plans and other platforms
Compare the current Free and paid plans, choose another platform on the official download page, and review the privacy policy. The gallery is an official publisher-provided inbox image from the press kit, not a screenshot from a mailbox created for this review.
Features
- Free hosted 10 GB mailbox
- One custom domain and five aliases on the Free plan
- Folders, labels, contacts and search
- Tracking-pixel and remote-image blocking
- OpenPGP support for compatible external recipients
- Open-source desktop and web clients
Requirements
- Windows 10 or later; x64 installer for this mirrored file
- macOS: universal package for Intel and Apple silicon; a minimum macOS version was not established from the official download page
- Linux: official x86-64 and ARM64 AppImage, .deb and .rpm packages; choose a package compatible with your distribution
- Web: current browser
- Aster account and internet access to use the hosted service