Aster Mail: Encrypted Email
Private email app with end-to-end encryption, aliases, and custom domains
| Repo: | F-Droid Main |
| AppID: | org.astermail.android |
| Author: | Aster Communications Inc. |
| License: | AGPL-3.0-or-later |
| InRepoSince: | 2026-09-09 |
| LastRepoUpdate: | 2026-10-01 |
| LastAppUpdate: | Unknown |
| LastVersion: | 0.6.192 |
| Categories: | |
| Google Play: | Check if it's there |
Aster Mail is a private, encrypted email app for astermail.org accounts.Your messages are encrypted on your device before they leave it. The server stores ciphertext and nothing else, so nobody at Aster can read your mail, scan it, or sell what is in it. There are no ads, no trackers, and no analytics anywhere in the app.
Private by design
- End-to-end encryption between Aster users, using a post-quantum ratchet protocol
- Zero-access architecture: the server holds only encrypted content
- No ads, no tracking, no telemetry, no profiling
- Open source under AGPL-3.0, so anyone can audit what the app does
Email aliases
- Create an alias for each site you sign up for, and turn one off when it starts getting spam
- See which alias a message arrived on, right in the message list
- Import and export your aliases
Your own domain
- Send and receive on a custom domain, with DKIM signing handled for you
- Buy a domain from inside the app
Everyday mail
- Folders, labels, categories, and search across your whole mailbox
- Swipe actions and a toolbar you can customize
- Templates, signatures, scheduled send, and auto-forwarding
- Blocked senders, sender filters, and an allow list
- Encrypted offline storage, so your mail is there without a connection
Security
- Biometric lock
- Two-factor authentication and a recovery key
- Active session management, so you can sign out a device you no longer have
Notifications
- Private mode hides the sender and subject on your lock screen
- Quiet hours schedule when notifications arrive
- Per-folder muting
This F-Droid build contains no Firebase or Google Play Services dependencies. Push notifications are delivered through any UnifiedPush-compatible distributor, such as ntfy. Background polling takes over when no distributor is installed.
Aster Mail is free to use. Paid plans add storage, larger attachments, more aliases, and custom domains.
Source code: https://github.com/Aster-Privacy/Aster-Android
WhatsNew:
What's new:
- You can sort folders A to Z and expand or collapse all of them at once.
- You can open password-protected PDFs and see Cc and Bcc in message details.
- You can choose the app language separately from your phone language.
Fixed:
- The app refreshes your session before it expires, so you stay signed in.
- When a message fails to send, the app tells you why.
- Images that you paste into a message send as attachments.
Anti-Features: NonFreeNet(this application promotes/depends a non-Free network service):
⇒ The app is a client for the astermail.org email service and cannot be used without an account there. That service is proprietary and hosted by its operator. Account registration and alias creation are additionally protected by Cloudflare Turnstile, a proprietary anti-abuse service.
While you can download the APKs here directly, you should preferably use an F-Droid client so the app stays up-to-date on your device.
Packages
Version 0.6.192 (2026-10-01) 
Android Versions:
- Target: 16.0
- MinVer: 8.0
- ABIs: arm64-v8a, armeabi-v7a, x86_64
Permissions:
Malware-Check:
Download (21.4 M)