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Penguin Mail is an open-source Rust mail client for Linux and macOS
Penguin Mail is a free, open-source mail and calendar client for Linux and macOS, written in Rust with GTK4, that collected 471 stars in the 27 days since its first commit.
Image: GitHub
Why it mattersA desk worker on Linux or macOS who wants an alternative to Thunderbird, Apple Mail or Outlook now has a native Rust client that already supports Gmail, Microsoft 365, OpenPGP and Google Calendar on day one.
A free, open-source mail and calendar client for Linux and macOS called Penguin Mail collected 471 stars in the 27 days since its first commit, the GitHub repository at c9dev/penguin-mail shows. The project is written in Rust and built on GTK4 and libadwaita, and runs on both desktop platforms as a native application.
The project's README positions it as a free alternative to the mail clients a desk worker reaches for now: Apple Mail on macOS, Mozilla Thunderbird on Linux, and Microsoft Outlook on either. The licence is GPL-3.0 and the GitHub API returns 23 forks, 15 open issues, three open pull requests and 2,509 commits on its main branch.
What it supports on day one
The README lists the account types the client already works with: Gmail and generic IMAP, Microsoft 365 and Outlook, calendar through Google Calendar and CalDAV, contacts through CardDAV, and the IMAP server-side filter language ManageSieve. Message protocols include IMAP, SMTP, POP3 and JMAP. End-to-end encryption and signing are supported through OpenPGP and S/MIME, which the project names in its description.
Features beyond the account connections, as the project describes them: conversation threading, multiple accounts in one window, calendar integration beside the mailbox, a contact manager, and what the README calls an AI assistant for productivity tasks. The author gives the AI feature one line and no further detail, so it is a feature claim rather than a measured capability.
Packaging and system requirements
The project ships through four Linux package channels and a macOS bundle: apt and dnf repositories, Flatpak, Snap, and a signed .pkg for macOS. The required toolchain is Rust 1.98 or newer, GTK 4 and libadwaita 1.8, which pins the project to recent desktop stacks on both operating systems. The GitHub API shows the main branch pushed within the last day, so the project is being worked on daily.
How to read the traction
The GitHub API returns the counts above: 471 stars, 23 forks, 2,509 commits over 27 days. The 471 to 23 stars-to-forks ratio sits in the normal range for an early project with real contributors rather than only star-botters, and the commit count is high enough to say the project is being written rather than announced. The project has not published a 1.0 release, so this is early software: a reader who switches to it now should expect to file issues and should keep a copy of their mail elsewhere.
For a Linux desktop user, the choices for a native, modern mail client are short, and most of them are either paid or carry a company's branding into the home. Penguin Mail joins the free list under GPL-3.0, written in a language that is becoming the default for new Linux desktop applications, with the calendar and encryption support that a work mailbox needs on day one.
Source
This item was written by an AI system from the linked source. Reveneau is responsible for what it publishes.
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