# Penguin Mail Mail and calendar for Linux and macOS, written in Rust. [![CI](https://github.com/c9dev/penguin-mail/actions/workflows/ci.yml/badge.svg)](https://github.com/c9dev/penguin-mail/actions/workflows/ci.yml) [![Latest release](https://img.shields.io/github/v/release/c9dev/penguin-mail?sort=semver&label=release)](https://github.com/c9dev/penguin-mail/releases/latest) [![License: GPL-3.0-or-later](https://img.shields.io/badge/license-GPL--3.0--or--later-blue)](LICENSE) [![Rust 1.98](https://img.shields.io/badge/rust-1.98-orange?logo=rust)](https://www.rust-lang.org) [![GTK 4 and libadwaita 1.8](https://img.shields.io/badge/GTK_4-libadwaita_1.8-4a86cf?logo=gnome)](https://gnome.pages.gitlab.gnome.org/libadwaita/) [Website](https://penguin-mail.com) · [Watch the tour](https://youtu.be/0PyJCsw1FSE) · [Install](#install) · [Features](#features) · [Screenshots](#screenshots) · [Changelog](CHANGELOG.md)

Penguin Mail is mail and calendar for Linux and macOS. It reads Gmail accounts, Microsoft accounts (Outlook.com, Hotmail, Live and Microsoft 365) and any IMAP and SMTP account, such as Fastmail, iCloud and Yahoo, and finds the server settings for you. It shows your accounts in one inbox or one at a time and keeps your mail on your own computer. On Linux, it can sync from the system tray. Gmail and Google Calendar accounts talk to Google directly, and Microsoft accounts talk to Microsoft Graph, so no other server sees your mail. It is built with GTK and libadwaita and fits best on GNOME. It also runs on other Linux desktops and macOS. On macOS, Settings lives in the native app menu. A new Gmail account signs in one of two ways, and you pick one for it: - **Set up your own Google project.** Every Gmail feature, on Linux and macOS: Gmail filters, the automatic reply, send-as aliases and signatures, and label colours. It takes about 10 minutes, once: Penguin Mail opens each Google page for you and says what to click. - **Use the Google account on this computer** (Linux), signed in through your computer's Online Accounts, or **a password from Google** elsewhere. Mail, calendar and contacts, without those four. Preferences shows what each account has. An account keeps the way it signed in. To change it, remove the account and add it again. [![A two-minute tour of Penguin Mail: play the video](docs/screenshots/tour.png)](https://youtu.be/0PyJCsw1FSE) ## Features Penguin Mail has mail for Gmail, Microsoft (Outlook.com, Hotmail, Live and Microsoft 365), IMAP and POP3 accounts, a calendar, contacts, OpenPGP and S/MIME, rules, and an optional assistant. An IMAP or POP3 account gets its calendar and contacts over CalDAV and CardDAV where the provider offers them, and an IMAP account its rules over ManageSieve. ### Reading - **One inbox for every account**, plus each account's Inbox, Flagged, Sent, Drafts and labels. A colored dot tells accounts apart. - **Conversations in one view.** Older messages fold down to a line, and quoted text and signatures are dimmed. HTML mail renders in its own sandbox with scripts off and remote images blocked until you ask for them. - **Categories.** A bar above the inbox splits it into Primary, Updates, Promotions and Social, using Gmail's own categories. Categorize Sender moves a sender to another category for good. - **Gmail search** with its full query syntax, across one account or all, with suggestions for subjects, people and labels as you type. - **Junk, Trash and All Mail**, for every account or one, read live from Gmail. Delete Forever asks you to confirm each time, and needs the permission signing in already asked for. ### Writing - **A composer that shows formatting as you write.** Recipients are chips, Cc and Bcc stay hidden until you want them, and attachments list their sizes. Replies and forwards thread correctly in Gmail, and drafts save to Gmail with their formatting, so they follow you to your phone. - **Markdown when you want it.** Turn Markdown into Formatting styles the Markdown in the body, and Write in Markdown goes back. Paste, drop or insert images into the text. - **Recipient suggestions** from your contacts and the people you have written to or heard from. - **Undo Send and Send Later.** Sent mail waits a few seconds with an Undo button. Send Later schedules a message, which goes out on time while Penguin Mail runs, even in the tray. - **An Outbox.** A message that cannot go out waits on this computer through a quit and a restart, and Penguin Mail tries again on a widening interval and as soon as the network comes back. Problems another try would not fix, such as a refused recipient or a message over Gmail's size limit, come back to you instead. - **Templates** you drop in at the cursor, and a spelling check while you write. ### Organizing - **Select several at once** with Ctrl+click, Shift+click or Ctrl+A, then archive, trash, junk, flag, mark or label them together. Ctrl+Z undoes each one. - **One message at a time.** Right-click a message inside a conversation to reply to it, archive it, trash it, mark it, flag it, label it or export it on its own. The rest of the thread stays where it is. - **Flags in seven colors**, as in Apple Mail. The flag syncs through Gmail's star, and the color stays on this computer. - **VIPs.** Their mail gathers in a VIPs mailbox, their rows get a star, and notifications can be limited to them. - **Smart Mailboxes**: saved conditions such as sender, subject, label, age, size or attachments, for all accounts or one. They search Gmail, so they reach past the mail kept on this computer. - **Remind Me** takes a conversation out of the inbox and brings it back, unread, when you choose. **Follow Up** lists mail you sent that has had no answer for three days. **Mute** keeps a noisy thread out of the inbox. - **Labels** from the toolbar or with `l`, nested as a tree under their account. Drag mail onto any mailbox or label to move it there. - **Export** a conversation or a selection as mbox, or one message as `.eml`. ### Gmail settings - **Rules**: Gmail's filters, listed in plain words, with a form to add one. - **Automatic replies** with a subject, message and optional dates. - **Unsubscribe and Block Sender.** List mail shows an Unsubscribe banner that uses the list's one-click link when it has one. - **Hide My Email.** Make a plus address, such as `you+kelp.ember795@gmail.com`, for each site you sign up to, and turn it off to send its mail to the Trash. Your real address stays visible inside it, so this stops lazy spam, not a determined sender. Gmail runs all four, so they work with your computer off. With Online Accounts or a password from Google, you change filters and the automatic reply on gmail.com. Your Gmail filters still run, and Penguin Mail links to the page. ### Calendar - **A calendar beside your mail.** Every calendar on every account, by day, week, month or a scrolling list, read from this computer. Answer Yes, Maybe or No on an invitation from its event, and search across every account's events. ### Security and privacy - **OpenPGP and S/MIME through your own GnuPG.** A signed message names its signer and says how far your trust database or the certificate chain vouches for it. An encrypted message opens and says it arrived that way. The composer has one Sign and one Encrypt for both standards and offers Encrypt once every recipient has a key. A Bcc stays blind under OpenPGP, which leaves that reader's key out of the message; S/MIME cannot, so a message with a Bcc is not encrypted under it. A draft of an encrypted message waits in Gmail encrypted to your own key, and opens again in the composer with Encrypt on. Penguin Mail holds no key and asks for no passphrase: gpg, gpgsm and their pinentry do. - **Remote content blocked twice**, by a WebKit content filter and by the page's own Content-Security-Policy, with JavaScript off. Loading images is a choice per conversation, or per sender. - **Invitations** show as a card above the message, and you can accept, decline or propose another time. ### The assistant An assistant pane (Ctrl+J) summarizes, sorts, cleans up, drafts replies and changes settings such as an automatic reply, using the app's own tools. It also reads and changes your Google Calendar, finds free time, looks people up in your contacts, and reads attachments. - **Any model, per job.** It runs on a local model (LM Studio, Ollama, or any OpenAI-compatible server), an Anthropic API key, or your Claude subscription through Claude Code, and translation can use a different model from the assistant. - **You see the work.** Each answer shows the model's thinking and every tool it ran, folded up until you open them, and a line saying what it is doing right now. - **Web search**, through Claude's own search or, for a local model, Brave Search, your own SearXNG, or Keenable with no key. - **MCP servers** you add give it more tools, and **skills** teach it your routines. A skill's scripts run in a sandbox with no access to your mail, keys or home folder. It asks before it sends mail, changes Gmail settings or your calendar, or uses a tool from outside the app, and it is off until you pick a model. [docs/assistant.md](docs/assistant.md) covers setup. ### On the desktop - **Tray and notifications on Linux.** An unread count in the tray, and new-mail notifications with Archive, Mark Read, Delete and Reply buttons. - **Light on memory on Linux.** In the tray Penguin Mail uses about 55 MB. A minute after you close the window, it restarts itself in the background to give back the memory the window used. - **Apple Mail's shortcuts on Linux** with Ctrl in place of Command, plus Gmail's single keys. - **American English, British English, French, German, Greek, Indonesian, Italian, Japanese, Korean, Polish, Romanian, Russian, Spanish, European Portuguese, Simplified Chinese, Traditional Chinese (Taiwan), Turkish, Ukrainian and Vietnamese**, chosen in Preferences, with the window's controls named for screen readers. ## Screenshots The screenshots show the Linux build. The macOS app uses the same views with a native app menu. ![All accounts in one inbox, with a reply open and its quoted history folded](docs/screenshots/inbox.png) ![An Outlook.com inbox with Focused and Other, and the account's tags in the sidebar](docs/screenshots/outlook.png) | Week | Month | Agenda | |---|---|---| | ![The calendar's week, with working hours shaded and each day's location](docs/screenshots/calendar-week.png) | ![The calendar's month, with a bar across the days of a trip](docs/screenshots/calendar-month.png) | ![The calendar's agenda, one line per event](docs/screenshots/calendar-agenda.png) | | Invitation | Event | |---|---| | ![An invitation in a message, with the hours around the meeting](docs/screenshots/invitation.png) | ![An event's details, guests and answers](docs/screenshots/event-popover.png) | | Dark | Writing | Narrow | |---|---|---| | ![The inbox in dark mode](docs/screenshots/dark.png) | ![Replying in the composer](docs/screenshots/composer.png) | ![The phone-width layout](docs/screenshots/phone.png) | | Several selected | Automatic reply | |---|---| | ![Three conversations selected, with bulk actions](docs/screenshots/selection.png) | ![The automatic reply dialog](docs/screenshots/automatic-reply.png) | | Flags | VIPs | |---|---| | ![A conversation flagged blue](docs/screenshots/flags.png) | ![A VIP in the sidebar and the list](docs/screenshots/vips.png) | | Assistant | Categories | |---|---| | ![The assistant listing mail that waits on a reply](docs/screenshots/assistant.png) | ![The inbox narrowed to Promotions](docs/screenshots/categories.png) | | Send Later | Rules | |---|---| | ![A message scheduled for Monday morning](docs/screenshots/send-later.png) | ![A Gmail filter in the Rules dialog](docs/screenshots/rules.png) | | Hide My Email | Preferences | |---|---| | ![Hide My Email, with one address and its switch](docs/screenshots/hide-my-email.png) | ![Preferences, with the calendar settings](docs/screenshots/preferences.png) | ## Install Penguin Mail runs on Linux x86_64 and macOS Apple Silicon and Intel. On Linux, the .deb, the rpm and the Arch package need GTK 4.20, libadwaita 1.8 and WebKitGTK 6.0 from your distribution, as Ubuntu 26.04, Fedora 43 and Arch's own repositories have; the snap brings its own. On Ubuntu 24.04 and the releases built on it, such as Pop!_OS 24.04 and Linux Mint 22, apt refuses the .deb for its older GTK and libadwaita; install the snap there. The Flatpak comes from Penguin Mail's own repository, not Flathub. On Linux, the tray icon needs a StatusNotifier host, which Ubuntu's AppIndicator extension provides. | | .deb | rpm | Arch | Flatpak | Snap | |---|---|---|---|---|---| | Updates | Install in the app, or `apt upgrade` | `dnf upgrade` | Download the new `.pkg.tar.zst` | `flatpak update` | Snap Store | | GnuPG | the system's | the system's | the system's | the runtime's, on your `~/.gnupg` | the snap's, on your `~/.gnupg` | | Assistant skills | yes | yes | yes | no | no | | Claude Code, and MCP servers you run as a command | yes | yes | yes | no | no | | Tray icon | yes | yes | yes | yes | yes | Skills are off in the Flatpak and snap because a skill's scripts run in a sandbox of their own, which cannot start inside either package's sandbox. Those sandboxes also keep the app from starting programs installed on your system, such as Claude Code. [docs/setup.md](docs/setup.md#which-package) has the details. ### On macOS Download the macOS zip for your computer from the [latest release](https://github.com/c9dev/penguin-mail/releases/latest): `macos-arm64` for Apple Silicon or `macos-x86_64` for an Intel Mac. Unzip it, move `Penguin Mail.app` to Applications, and open it from Finder. The bundle includes its GTK libraries, so you do not need Homebrew to run it. The app bundle records the minimum macOS version each build requires. The macOS builds are not notarized yet, so their zips end in `-unsigned` and macOS blocks the first launch. Open the app once, then go to System Settings → Privacy & Security and choose Open Anyway; from then on it opens normally. Notarized builds will come with the first release after the Apple certificates are in place. To update, download the next macOS zip and replace the app in Applications. Your mail and settings stay in your user folder. The macOS app has no tray icon. GnuPG and command-line assistants are not bundled. ### With apt (recommended on Ubuntu) Penguin Mail has its own apt repository. Add its key and entry, then install: ```sh sudo curl -fsSLo /usr/share/keyrings/penguin-mail-archive-keyring.gpg \ https://c9dev.github.io/penguin-mail/penguin-mail-archive-keyring.gpg sudo curl -fsSLo /etc/apt/sources.list.d/penguin-mail.sources \ https://c9dev.github.io/penguin-mail/penguin-mail.sources sudo apt update && sudo apt install penguin-mail ``` `sudo apt upgrade` then brings each new version with the rest of the system. The key's fingerprint is `FE3C 3B6E 699A F939 DC46 70DC F3A8 5303 5C3E 2B8E`. ### From a release Download the `.deb` from the [latest release](https://github.com/c9dev/penguin-mail/releases/latest) and install it, replacing `X.Y.Z` with the version: ```sh sudo apt install ./penguin-mail_X.Y.Z_amd64.deb ``` apt pulls in the libraries it needs. The `.deb` also adds the apt repository above, so later versions arrive with `sudo apt upgrade`. ### Without root The same release has a tarball and a zip that install under `~/.local`: ```sh tar xzf penguin-mail-X.Y.Z-x86_64.tar.gz cd penguin-mail-X.Y.Z-x86_64 ./install-files.sh . ``` It starts in the tray at login unless you run it as `NO_AUTOSTART=1 ./install-files.sh .`. To check a download, fetch the release's `SHA256SUMS` and `SHA256SUMS.asc` and the apt repository's key from above, then: ```sh gpgv --keyring ./penguin-mail-archive-keyring.gpg SHA256SUMS.asc SHA256SUMS sha256sum -c --ignore-missing SHA256SUMS ``` ### With dnf, on Fedora Penguin Mail has a dnf repository beside the apt one, signed with the same key: ```sh sudo curl -fsSLo /etc/yum.repos.d/penguin-mail.repo \ https://c9dev.github.io/penguin-mail/rpm/penguin-mail.repo sudo dnf install penguin-mail ``` dnf asks you to accept the key the first time. `sudo dnf upgrade` brings each new version, and the `.rpm` on the releases page adds the repository too. ### With Flatpak Install from Penguin Mail's signed Flatpak repository: ```sh flatpak install --user https://c9dev.github.io/penguin-mail/flatpak/penguin-mail.flatpakref ``` The install adds the repository, so `flatpak update` brings later versions. The GNOME runtime comes from Flathub. The repository uses the signing key shown under apt above. ### On Arch [![penguin-mail on AUR](https://img.shields.io/aur/version/penguin-mail?label=penguin-mail)](https://aur.archlinux.org/packages/penguin-mail/) [![penguin-mail-bin on AUR](https://img.shields.io/aur/version/penguin-mail-bin?label=penguin-mail-bin)](https://aur.archlinux.org/packages/penguin-mail-bin/) ```bash # Build release package from source yay -S penguin-mail # OR install the binary release yay -S penguin-mail-bin ``` ### From the Snap Store ```sh sudo snap install penguin-mail --edge ``` The snap waits for the Snap Store to approve its access to `~/.gnupg` and to the keyring, and the command above finds it once the store has. New versions reach the edge channel first. The snap is strictly confined, and signing and encryption use your own keys. ### From source [CONTRIBUTING.md](CONTRIBUTING.md#building-from-source) has the steps, and how to build the Flatpak yourself. With Nix, `nix run github:c9dev/penguin-mail -- --demo` runs the app on sample mail. See [the Nix guide](docs/nix.md) for installation and account sign-in. ### First run The first window offers **Add your first account**. Pick a provider and follow the steps; **Add Account** in the sidebar adds each account after that. For a Gmail account, Penguin Mail asks **Choose how Penguin Mail signs in to Gmail** and lists the ways it offers. Pick one. If you pick one that opens Google's page in your browser, Google may show a warning page first; choose **Advanced**, then continue to Penguin Mail. ### Updates A Penguin Mail installed on Linux from the .deb, tarball or source checks GitHub for a new release once a day. When one is out, it says so in a notification, a banner across the window, and the tray menu, and **Install** does the rest: - **From the .deb or the apt repository**, it downloads the new `.deb` and installs it with apt. GNOME asks for your password, because apt changes files under `/usr`. `sudo apt upgrade` installs the same version, if you would rather update that way. - **From the tarball or from source**, it downloads the new tarball and installs it into the same folder as before, with no password. Before it installs anything, Penguin Mail checks that the release's `SHA256SUMS` carries a good signature from the apt repository's key, which is built into the app, and then checks the download against those sums. It refuses a release whose signature is missing or made by any other key, and the update log says so. Once the new version is in, Penguin Mail restarts into it. With a message open in the composer, it waits and shows **Restart** instead, since a draft saves only when you save it. **Check for Updates** in the tray menu checks at once. To stop the daily check, turn off **Check for Updates** under Preferences, Startup. A copy run with `cargo run` or as the demo never checks. The rpm leaves updates to dnf, and the snap to the Snap Store. Those copies never check GitHub and offer no Install of their own; Preferences and the About window say who brings updates. The macOS app has no in-app installer. Download the next macOS zip from the releases page and replace `Penguin Mail.app` in Applications. To update by hand, download the new release and install it the same way as the first time. For a copy built from source, pull and run `scripts/install.sh` again. ### Try it without an account ```sh penguin-mail --demo ``` On macOS, run `"/Applications/Penguin Mail.app/Contents/MacOS/penguin-mail" --demo` from Terminal instead. The demo opens three sample accounts in a throwaway store. Search, triage, the composer and attachments all work against sample data, and nothing talks to Google. ## Usage ### Keyboard On Linux, Apple Mail's shortcuts work with Ctrl in place of Command. Gmail's single keys work whenever you are not typing. `Ctrl+?` lists every shortcut. On macOS, open **Keyboard Shortcuts** from the window's main menu to see the keys for that build. | Key | Action | Key | Action | |---|---|---|---| | `j` / `k` | Next / previous conversation | `Ctrl+R` or `r` | Reply | | `Ctrl+Alt+A` or `e` | Archive | `Ctrl+Shift+R` or `a` | Reply all | | `Delete` or `#` | Move to trash | `Ctrl+Shift+F` or `f` | Forward | | `Ctrl+Shift+J` | Junk | `Ctrl+N` or `c` | New message | | `Ctrl+Shift+L` or `s` | Flag or unflag | `Ctrl+Shift+D` | Send | | `Ctrl+Alt+1` to `Ctrl+Alt+7` | Flag color | `Ctrl+Shift+A` | Attach files | | `Ctrl+Shift+U` or `u` | Mark read or unread | `Ctrl+B` / `Ctrl+I` / `Ctrl+K` | Bold, italic, link | | `Ctrl+Alt+M` or `l` | Labels | `Ctrl+F` or `/` | Search | | `Ctrl+Z` | Undo | `Ctrl+1` to `Ctrl+9` | Open a mailbox | | `Ctrl+A` | Select all | `Ctrl+=` / `Ctrl+-` / `Ctrl+0` | Text size | | `Ctrl+Shift+N` or `F5` | Check for mail | `Ctrl+P` | Print | | `Ctrl+O` or double-click | Open in a new window | `Ctrl+Alt+U` | View source | ### Command line ```sh penguin-mail --background # on Linux, start in the tray penguin-mail --compose # new message penguin-mail mailto:ann@example.com # new message to Ann penguin-mail --version ``` On Linux, to make Penguin Mail open `mailto:` links: ```sh xdg-mime default io.github.c9dev.PenguinMail.desktop x-scheme-handler/mailto ``` On Linux, the running app answers D-Bus actions, for custom shortcuts: ```sh gdbus call --session --dest io.github.c9dev.PenguinMail --object-path /io/github/c9dev/PenguinMail \ --method org.gtk.Actions.Activate show-window [] {} ``` The actions are `show-window`, `hide-window`, `compose`, `check` and `quit`. When built from source, `penguin-mail-cli` drives the same sync core without a window: `account add`, `sync`, `threads`, `show`, `triage` and `export`. ## Privacy - Penguin Mail talks to Google's APIs straight from your computer. No Penguin Mail server sits in between. - Refresh tokens live in Keychain on macOS or the desktop keyring on Linux. The config file holds sync settings and, for accounts added through the old setup page, their Google client ID and secret, readable by you alone. - Mail is cached in `~/.local/share/penguin-mail` on Linux or `~/Library/Application Support/penguin-mail` on macOS: the last 30 days plus everything in your inbox. Opening an older thread fetches it on demand. - The assistant is off until you pick a model. A local model keeps mail on your computer; the Anthropic API and Claude Code send what the assistant reads to Anthropic. API keys live in the same credential store. The full policy is in [docs/privacy-policy.md](docs/privacy-policy.md). ## Help and feedback Questions, bug reports and ideas are welcome in [Issues](https://github.com/c9dev/penguin-mail/issues). [CONTRIBUTING.md](CONTRIBUTING.md) says what a useful report holds, and how the code is built and tested. [SECURITY.md](SECURITY.md) says where to send a vulnerability. ## License Penguin Mail is free software under the [GNU General Public License, version 3 or later](LICENSE). The icon is a penguin holding a letter, drawn on the rounded square and bevel of the Gruvbox Plus icon pack so it sits among that pack's apps.