Flectar Mail

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Email, made fast again

Built from the ground up for speed. Flectar Mail delivers native performance, instant startup, and as little as 80 MB of RAM.

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Flectar Mail on macOS showing the unified inbox and message view

Flectar Mail is a lightweight, native home for your email, calendars, and contacts. It is engineered to open instantly, stay responsive, and use a fraction of the memory of a typical web-based mail client. ## ❓ Why Flectar Mail? - **Fast from the first click.** A native interface and local-first data path get you to your inbox without waiting on a browser runtime. - **As little as 80 MB of RAM.** Flectar Mail is deliberately designed to keep memory use low, even with a full-featured inbox at your fingertips. - **Everything in one place.** Move between mail, calendars, and contacts without stitching together separate apps. - **Offline by design.** Your mailbox and calendar are stored locally, so your synced data remains useful without a connection. - **Works with your accounts.** Connect Gmail, Outlook and Microsoft 365, or standards-based IMAP, POP3, SMTP, JMAP, CalDAV, and CardDAV services. - **Privacy-conscious defaults.** Remote images are blocked until you allow them, helping prevent tracking pixels from reporting when you read a message. - **Security by architecture.** Email content is never opened in a WebView. Flectar Mail renders HTML and CSS through its own Rust-native pipeline, does not execute email scripts, and blocks remote images by default. This avoids the embedded-browser attack surface by design. - **An experimental Rust renderer.** Building an email renderer without a browser engine is new territory. Rendering issues are expected, especially in complex messages, while compatibility continues to improve. - **Made for every screen.** Spacious and minimal desktop layouts share the same experience as the touch-friendly compact interface. - **Native and open source.** Built from the ground up with Rust. It is not a browser wrapped in a window, and it is released under the AGPLv3. ## 📁 Files and attachments Browse JMAP/WebDAV storage, search mail attachments, keep files offline, and preview PDFs, images and text. ## ✍🏻 Account signatures and OpenPGP Settings → Accounts → Signatures & OpenPGP provides named signatures, separate new-message and reply defaults, and a composer signature selector. Desktop OpenPGP/MIME signing and encryption use installed GnuPG 2.x with pinentry for private-key passphrases. Required encryption blocks delivery when recipient keys are missing or invalid; protected drafts remain local until Send. S/MIME and mobile OpenPGP are not currently supported. ## 🧪 Experimental HTML rendering > [!WARNING] > HTML email rendering is currently the most experimental part of Flectar Mail. > Some messages, especially those with complex or unusual markup and CSS, may > not render correctly yet. To keep the client fully native and memory usage around 80 MB, Flectar Mail renders email HTML with [Blitz](https://github.com/DioxusLabs/blitz), a Rust HTML/CSS renderer from the Dioxus team, instead of embedding a browser or WebView. Desktop builds include **CPU — Low Memory** and **GPU — WGPU** under Settings → General → Renderer. CPU is selected initially and does not initialize WGPU. The GPU option uses Slint and Vello on a shared WGPU 30 device; changing the setting takes effect after restarting the app. A failed GPU startup falls back to CPU automatically. As far as we know, Flectar Mail is one of the first projects using Blitz for arbitrary, real-world email HTML. Email markup contains plenty of unusual HTML and CSS, so this pushes the renderer into demanding territory. We currently carry several patches on top of Blitz and hope to upstream as much of that work as possible over time. If you find an email that renders incorrectly, please [report it](https://github.com/flectar/mail/issues). This approach is still experimental, but it is also a major reason Flectar Mail can remain so lightweight compared with WebView-based clients built with frameworks such as Tauri or Wails. ## 🎨 Make it yours Choose the workspace that fits the way you handle email. Keep the detailed three-pane layout, switch to a streamlined minimal view, choose a light or dark theme, select a built-in color palette or create a custom one, and show or hide sender avatars. You can also give the app icon a different color: on the taskbar or Dock, in the system tray, in the Linux app launcher, and on Android and iOS home screens. Message appearance can follow the app theme or stay light or dark independently. It uses your selected color palette for HTML, plain text, and Reader mode. To temporarily show the sender's original colors, use the contrast icon between Find and Reader mode in the desktop message toolbar, or choose **Show original colors** from the message's three-dot menu on any screen size. The full workspace keeps your folders, message list, and selected email visible together. The minimal layout reduces visual noise and gives each part of your inbox more room when you need it. ### 👥 Profiles and account colors Group related accounts into named profiles such as Work or Personal, then give each profile its own color. Create a profile from the profile menu at the start of the tab bar, or in Settings → Accounts → Profiles, and check the accounts that belong to it. Choose a profile in that menu to focus the mail view on its accounts: the unified inbox, search, counts, and sidebar show only their mail, while your tabs stay the same. **All accounts** shows everything again. You can also override an individual account's color and show the effective color along the left edge of every message. The markers make accounts easy to tell apart while working in the unified inbox; the example below uses purple for Work and orange for Support.

### 🧵 Conversation threads Replies stay grouped in chronological order, with the active message expanded inside the reading pane. Use **Up/Down** to navigate messages, **Home/End** to jump to the first or last loaded message, and **Page Up/Page Down** to move a page at a time. **Enter** opens the current message and focuses its content; **Space** checks or unchecks it for bulk actions. **Tab/Shift+Tab** move between controls. In the full workspace, **F6** moves focus between the message list and reader. In the minimal layout, arrow keys highlight messages and **Enter** opens them; **Escape** or **F6** returns to the list.

Flectar Mail conversation with incoming and replied messages

### 🗂️ Tabs Keep several places open at once with browser-style tabs. Each tab remembers its own place: a mailbox, search, or open conversation, the calendar, contacts, files, or Settings, along with how far you scrolled the list and the message you were reading. Middle-click or Ctrl/⌘-click a message to open it in a background tab (add Shift to switch to it), or choose **Open in new tab** from its menu. Drag tabs to reorder them, middle-click a tab to close it, right-click a tab to close the others or those to its right, and pick up where you left off the next time you open Flectar Mail. **Ctrl/⌘+T** opens a new tab, **Ctrl/⌘+W** closes the current one, and **Ctrl/⌘+Shift+T** reopens the last tab you closed. **Ctrl+Tab** and **Ctrl+Shift+Tab** cycle through tabs, **Ctrl/⌘+1–8** jump to a tab, and **Ctrl/⌘+9** jumps to the last.

Flectar Mail with tabs for several conversations, the calendar, contacts, and files

### Full and minimal workspaces

Full workspace	Minimal workspace

### Color palettes

Teal	Green	Purple	Custom

### 🪟 Frameless window Turn on **Frameless window** in Settings → General → Interface to replace the system title bar with window controls in the toolbar. Each platform keeps its own behavior: macOS keeps the native traffic lights, Windows keeps Snap Layouts and the system menu, and Linux follows the button order and title-bar actions configured for GNOME or KDE.

macOS	Windows

Linux (GNOME)	Linux (KDE)

### 📅 Calendar, contacts, and files

Calendar	Contacts	Files (WebDAV/JMAP)

### 💾 Storage and backups Settings → Storage shows how much space mail, attachments, offline files, and databases use on the device. From the same page, you can export verified database snapshots or transfer connected-account setup and preferences through a backup. Passwords and OAuth tokens stay in the system keyring, so a restored device asks you to sign in again. POP3 accounts download mail to this device and leave it on the server unless you choose otherwise: each account can remove mail from the server after 7, 14, or 30 days, once you delete it here, or as soon as it's downloaded, but never before it's stored on this device. Their folders exist only on this device, so snapshots include that mail, and removing a POP3 account or deleting all data offers to export it first as mbox files, one per folder, which other mail apps can import. The same import also brings accounts over from Thunderbird (a profile folder, its Tools › Export archive, or `prefs.js`) and from Thunderbird for Android or K-9 Mail (`.k9s` settings exports). You review each account before anything is added: settings Flectar Mail can't reproduce, such as an Exchange server, are explained instead of changed silently, and POP3 accounts keep their rule for removing mail from the server. Existing accounts are never modified, and passwords are never imported. Saved mail comes over the same way: Thunderbird's Local Folders and the mail its POP3 accounts downloaded, mbox files such as a Google Takeout export or Flectar Mail's own, `.eml` messages, maildir folders, Apple Mail mailboxes, and ZIP archives of them. You pick the files, several at once if you like, then the folders, with Trash and Junk left out unless you check them, and the folder structure and read and starred states come along. Mail that's already there is skipped, so a stopped import can simply run again, and a long one can carry on in the background. Mail that belongs to no account goes to **On this device**: folders kept only here, which Settings → Storage can export or delete. It can also go into a POP3 account's folders, or up to the server of an IMAP, JMAP or Gmail account, into a folder of its own there.

Flectar Mail Storage settings with local usage, mail on this device, database snapshot, and account backup controls

### 📱 Made for smaller screens The compact interface keeps the important actions within reach while giving messages, events, and contacts the full screen when they need it. | Light | Dark | | --- | --- | | ![Flectar Mail mobile inbox in light mode](resources/screenshots/mobile-light.png) | ![Flectar Mail mobile inbox in dark mode](resources/screenshots/mobile-dark.png) | ## 📥 Get Flectar Mail Flectar Mail is currently in development and is not yet stable. > [!WARNING] > **Google OAuth verification requires an annual CASA security assessment.** > Flectar is a community open-source project, so completing this assessment > depends on sponsor support. Until the required verification is funded and > complete, a stable release with Gmail OAuth configured by default will not be > possible. If you want to help make built-in Gmail sign-in available, please > [sponsor Flectar](https://github.com/sponsors/flectar). > > Google and Microsoft OAuth verification is still in progress. Earlier GitHub > prereleases are intended for testers using their own OAuth registrations or > IMAP, POP3, or JMAP accounts. Builds without OAuth app keys keep Gmail and Outlook sign-in disabled. Use the **Sign-in settings** cog on the welcome screen to save your own Google or Microsoft app registration, or connect an IMAP, POP3, or JMAP account. Custom keys are shared with Settings and take precedence over bundled keys; clearing a custom client ID restores the defaults when available. Each provider enables separately once its configuration is saved. When preview builds are published, download them from [GitHub Releases](https://github.com/flectar/mail/releases) and look for the **Pre-release** badge: - **Linux x64:** AppImage, Debian/Ubuntu `.deb`, Fedora 43/44 `.rpm`, or a sideloaded Flatpak preview bundle - **Windows x64:** Setup `.exe` or portable ZIP - **macOS Apple silicon or Intel (macOS 14+):** DMG or application ZIP - **Android arm64 (Android 8.0+):** Signed APK; previews and stable releases share one app identity Windows previews are unsigned; macOS previews are ad-hoc signed and not notarized, so operating-system security prompts are expected. Install updates manually. The Flatpak preview is provided as a standalone test bundle. It is not yet a Flathub package and therefore does not receive automatic Flathub updates. Its close-to-tray option is disabled until the tray backend can use a sandbox-safe D-Bus name. Starting automatically at sign-in goes through the desktop's Background portal and opens the window, because there is no tray to start into. The app icon stays orange there, because the sandbox cannot change the launcher icon on the host. Install the downloaded Linux package with either `sudo dnf install ./flectar-mail--linux-x64.rpm` or `flatpak install --user ./flectar-mail--linux-x64.flatpak`. Launch the Flatpak with `flatpak run com.flectar.mail`. The RPM targets Fedora 43 and 44 on x86_64. Release builds use Fedora 43 as their compatibility baseline; the same RPM must pass installation, PDF rendering, X11 and Wayland startup, and removal checks in clean containers for both versions before publication. Other RPM-based distributions are not yet tested. If Discover reports a generic conflict, run the `dnf install` command above and include its dependency error in your bug report. The older `0.1.0-alpha.7` RPM was built on Fedora 44 and cannot install on Fedora 43 because it requires glibc 2.43. Its Flatpak bundle is an alternative while waiting for an RPM release built with the compatibility checks above. Each GitHub release includes `SHA256SUMS` and signed build-provenance attestations. With GitHub CLI installed, verify a download with `gh attestation verify --repo flectar/mail`. Starting with alpha 8, Android alpha, beta, release-candidate, and stable builds use one package (`com.flectar.mail`) and one persistent signing identity. Later versions can update the app in place and retain local data. Alpha 6 and alpha 7 used different keys and cannot update to this signing identity. Both Android release workflows use the `android-release` GitHub environment. They require the same keystore and password secrets, verify the public certificate against `platform/android/app-signing-certificate.sha256`, and derive Android version codes from the release version. A missing or different key blocks publication. **Do not generate a replacement key or change the pinned fingerprint for a routine release.** Password changes preserve the identity when the original private key and certificate are retained. See [Android signing setup and recovery](docs/android-signing.md) for the one-time migration command, required secrets, backups, and Play App Signing. Local developer builds can still generate a local test key. They only update installations signed with that same local key. You can also build Flectar Mail from source with the [Rust toolchain](https://rustup.rs/): ```bash cargo run --bin flectar-mail ``` Linux desktop OAuth uses the system browser through the desktop portal and stores refresh credentials through the freedesktop Secret Service. A normal desktop session therefore needs an `xdg-desktop-portal` backend and a Secret Service provider such as GNOME Keyring. Release builds stop before opening the OAuth page when secure credential storage is unavailable, so an authorization grant can never be completed without a safe place to persist it. Podman and Docker development shells commonly have neither the host session D-Bus nor the host browser's loopback network. Debug builds support that setup with a clearly marked, owner-only development credential file and an accordion for pasting the final loopback callback URL. The file backend is excluded from release builds. ## 🌍 Help translate Flectar Mail Flectar Mail is built for everyone, and we'd love your help making it available in more languages! We're using [Weblate](https://translate.flectar.com/) to manage community translations. Whether you'd like to translate Flectar Mail into your native language, improve an existing translation, or help review translated strings, every contribution is welcome. **[Start translating Flectar Mail →](https://translate.flectar.com/)** Getting started is easy: 1. Create an account on our translation platform. 2. Select your language, or start a new translation if it isn't available yet. 3. Translate strings directly through Weblate, no programming or GitHub experience required. Translations are synchronized with our GitHub repository and submitted as pull requests for review. Contributors can also receive GitHub attribution for their work. README translations are maintained in this repository. See [Contributing translations](CONTRIBUTING.md#translations) to add or update one. ## ♿ Accessibility Flectar Mail includes keyboard navigation, light and dark themes, and flexible layouts. Accessibility work is ongoing. See [ACCESSIBILITY.md](ACCESSIBILITY.md) for current features, testing limitations, and how to report a barrier. ## 🔒 Security To report a vulnerability privately, follow [SECURITY.md](SECURITY.md). Please keep vulnerability details out of public issues. ## 🌐 Open source, for everyone Flectar Mail is one open-source application. There is no separate community edition. The client is licensed under the [GNU Affero General Public License v3](LICENSE). Read the [licensing overview](LICENSING.md) for the practical details, or see [CONTRIBUTING.md](CONTRIBUTING.md) to help shape the project. ## 🫡 Acknowledgements Flectar Mail is made possible by the work of these projects and their contributors: - [Slint](https://slint.dev/), the native UI toolkit that powers the Flectar Mail interface. - [Blitz](https://github.com/DioxusLabs/blitz), the Rust HTML/CSS renderer from the Dioxus team that powers the email reading experience. ---