Aster Mail is a free, open-source, end-to-end encrypted mail service. Every message subject line and attachment is encrypted locally on your device. This means we have no way to read your email and we never will.
You can sign up at astermail.org. A phone number and recovery email are not required.
All Aster-to-Aster messages are end-to-end encrypted using the standard OpenPGP (Ed25519 and Curve25519). Subject lines are also encrypted. This means that we cannot read your subject lines, unlike other providers. Aster-to-Aster messages also use ML-KEM-768 inside an X3DH and Double Ratchet protocol, which protects against store-now-decrypt-later attacks.
Your keys are yours, and they are fully portable. You can export them and use them with GPG or any OpenPGP client. Public keys are published through WKD and key servers automatically, so encrypting to other Aster users happens without any setup.
Aster runs on a zero-access architecture located in Germany. This means we store nothing we could hand over, even if we were compelled.
Go to astermail.org to create a free account. If you would like to contribute code to Aster, see CONTRIBUTING.md for instructions.
You can build Aster Mail yourself from this repository. It builds into a web bundle and a desktop app for Windows, macOS, and Linux. There is no account or API key involved, and you do not need to write a .env file. These are the same steps our release workflow runs.
You will need Node.js 20 or later and a stable Rust toolchain. On Debian or Ubuntu, the desktop build also needs a few system libraries:
sudo apt-get install libwebkit2gtk-4.1-dev libayatana-appindicator3-dev librsvg2-dev libxdo-dev libssl-dev build-essential fileAster Mail shares its interface components with our other apps through aster-ui, so you will need to clone it next to Aster Mail and build it first. Installing will fail if it is not there:
git clone https://github.com/Aster-Privacy/aster-ui.git
git clone https://github.com/Aster-Privacy/Aster-Mail.git
cd aster-ui && npm install && npm run build
cd ../Aster-Mail && npm install --forceTo build the web app:
npm run buildThe build is written to dist/. You can serve it with any static web server.
The desktop app updates itself through GitHub Releases, so Tauri asks for a signing key even on a local build. Generate one once. It will only ever sign your own builds, and you can leave the password empty:
npm run tauri signer generate -- -w ~/.aster_updater.key
export TAURI_SIGNING_PRIVATE_KEY=$(cat ~/.aster_updater.key)
export TAURI_SIGNING_PRIVATE_KEY_PASSWORD=""
npm run tauri:buildInstallers and binaries are written to src-tauri/target/release/bundle/.
The Android project in this repository is a development wrapper. The app we publish to Google Play is built from Aster-Android.
Join our Discord to share feedback, ask questions, and contribute to the privacy community. You can also find us on X and Reddit.
If you have any questions or security disclosures, email us at hello@astermail.org or security@astermail.org. Do not open a public issue for security vulnerabilities. Read SECURITY.md for the full security vulnerability disclosure process.
We welcome contributions of all kinds. Read CONTRIBUTING.md before opening a pull request.
By contributing to any Aster repository, you agree that your contributions will be licensed under AGPL v3.