Astroid

Free plan LinuxMacWindows

What Astroid is

Astroid is a free, open-source desktop mail user agent for Linux, macOS and Windows. It searches, displays, composes and organizes email in threads and tags, using the notmuch backend for search. Other programs must fetch, synchronize, index and send messages; the project’s typical setup uses OfflineIMAP, notmuch and msmtp, with vim or emacs as an editor. The interface is fully keyboard-operable, and buffers can be arranged in separate windows. Astroid displays HTML mail and common attachments inline, provides syntax highlighting for patches and code segments, and supports PGP/MIME cryptography. Themes and configuration can be adjusted, and Python and Lua plugins are supported. Editors may be embedded or external, including vim, emacs or other choices. The project documents cloning its source and compiling with CMake, with installation guidance including /usr/local/bin and Linux distributions such as Arch Linux, Ubuntu, Debian, Fedora and NixOS. Configuration effort varies by provider, and Gmail needs special configuration.

Who it suits

It suits desktop users who want a keyboard-driven graphical interface around notmuch. Users must be comfortable configuring separate mail-fetching, synchronization and sending programs.

What it does well

Free and open source
Keyboard-operable interface
Threads and tags organize email
Inline HTML and attachment display
Python and Lua plugins supported

What to know first

Requires other programs for mail transport
Configuration varies by provider
Gmail needs special configuration
Builds from source with CMake

Plans

Plan	Billed and limits	Price
Astroid	Graphical email client for Notmuch · requires other programs for fetching, syncing and sending email	Free

As astroidmail.github.io lists them, read 12 Oct 2026. The maker's own page has the final word.

Verdict

Astroid offers a customizable graphical front end for a notmuch-based mail setup. Its reliance on separate programs and source-build instructions makes it better suited to users willing to configure their own mail stack.

Facts from Astroid's own pages

App coverage: desktop · astroidmail.github.io, 20 Sept 2026
Code display: Astroid provides syntax highlighting for patches and code segments. · github.com, 12 Oct 2026
Customization: The interface is themable and configurable. · github.com, 12 Oct 2026
Display: Astroid displays HTML mail and common attachments inline. · github.com, 12 Oct 2026
Distribution: The project README provides instructions to clone the source repository and build Astroid with CMake. · github.com, 5 Oct 2026
Editors: Astroid supports embedded or external Vim or Emacs editors, as well as other editors. · github.com, 12 Oct 2026
Encryption: Astroid has built-in PGP/MIME cryptography support. · github.com, 12 Oct 2026
Installation: The project documents compiling Astroid from source using CMake and installing its binary. · github.com, 12 Oct 2026
Interface: The interface can be operated by keyboard and its buffers can be placed in separate windows. · github.com, 5 Oct 2026
Keyboard use: The interface is fully operable by keyboard. · github.com, 12 Oct 2026
Mail handling: Astroid relies on other programs to fetch, sync, index, and send email. · github.com, 5 Oct 2026
Mail setup: Astroid relies on other programs for fetching, syncing and sending email. · github.com, 12 Oct 2026
Message display: Astroid can display HTML mail and common attachments inline. · github.com, 5 Oct 2026
Platform evidence: The README describes installing the astroid binary under /usr/local/bin, and the project wiki lists setup instructions for Linux distributions including Arch Linux, Ubuntu, Debian, Fedora, and NixOS. · github.com, 5 Oct 2026
Plugins: Astroid supports Python and Lua plugins. · github.com, 12 Oct 2026
Product: Astroid is a lightweight graphical mail user agent for searching, displaying, composing, and organizing email in threads and tags. · astroidmail.github.io, 5 Oct 2026
Purpose: Astroid is a lightweight mail user agent for searching, displaying and composing email organized in threads and tags. · astroidmail.github.io, 12 Oct 2026
Search: Astroid uses the notmuch backend to search through email. · astroidmail.github.io, 12 Oct 2026
Setup limit: The project says configuration effort can vary by email provider and that Gmail requires special configuration. · github.com, 5 Oct 2026
Support: Users can report issues on GitHub or contact the project mailing list. · github.com, 12 Oct 2026
Typical setup: The project describes a typical setup using OfflineIMAP, notmuch, msmtp, and Astroid, with vim or emacs as an email editor. · github.com, 5 Oct 2026

Where Astroid stands on Freedom251

Email clients#80 of 142