Outlook Lite for Linux

Lightweight, native Microsoft Outlook client for Linux using CEF (Chromium Embedded Framework) and C++20.

No Electron. No Node.js. A native C++ app with Chromium rendering, Wayland support, and persistent sessions.

Features

• Chromium-based rendering via CEF (Chromium 133) — full Outlook web compatibility
• Native Wayland support with GPU acceleration
• Persistent sessions — login once, stay logged in
• System tray with unread badge count
• Desktop notifications for new emails
• Ad popup blocking (network-level)
• Frameless window mode (configurable)
• Close-to-tray (configurable)
• Window state persistence (position + size)
• Custom CSS injection (~/.config/ofl/custom.css)
• OAuth popup handling for Microsoft sign-in
• Auto-download attachments to ~/Downloads
• Keyboard shortcuts (F5 reload, Ctrl+Shift+R bypass cache, F12 devtools, Ctrl+Q quit)
• Single-instance enforcement
• Spellcheck with context menu suggestions
• CI packaging: .deb, .rpm, .pkg.tar.zst, binary tar.gz

Install

Build from source

# Dependencies (Ubuntu/Debian)
sudo apt install build-essential cmake pkg-config curl patchelf \
  libgtk-3-dev libayatana-appindicator3-dev libnotify-dev libnss3-dev

# Dependencies (Fedora)
sudo dnf install gcc-c++ cmake pkg-config curl patchelf \
  gtk3-devel libayatana-appindicator-gtk3-devel libnotify-devel nss-devel

# Dependencies (Arch)
sudo pacman -S cmake pkg-config gtk3 libayatana-appindicator libnotify nss curl patchelf

# Download CEF (official minimal distribution, ~350MB)
bash packaging/download-cef.sh /tmp/cef-ofl

# Build
cmake -B build -DCMAKE_BUILD_TYPE=Release -DCEF_ROOT=/tmp/cef-ofl
cmake --build build -j$(nproc)

# Run
./build/ofl

Packages

Pre-built packages (.deb, .rpm, .pkg.tar.zst) are available on the Releases page.

Configuration

Config file: ~/.config/ofl/config

# Default URL (outlook.office.com for work, outlook.live.com for personal)
url = https://outlook.office.com

# Window size
width = 1280
height = 800

# Enable browser developer tools (F12)
dev_tools = false

# Minimize to tray on close
close_to_tray = true

# Start minimized to tray
start_minimized = false

# Frameless window (no title bar)
frameless = true

Data directories

Path	Purpose
~/.config/ofl/config	Configuration file
~/.config/ofl/custom.css	Custom CSS (injected on page load)
~/.local/share/ofl/	Cookies, IndexedDB, session data (persistent)
~/.cache/ofl/	HTTP cache (disposable)

Environment variables

Environment variables override the config file:

Variable	Description
OFL_URL	Override default URL
OFL_WIDTH	Override window width
OFL_HEIGHT	Override window height
OFL_DEV_TOOLS	Enable devtools (true/1)

Related

• Teams Lite for Linux (TFL) — sister project for Microsoft Teams, using custom CEF with WebRTC/H.264/PipeWire support

License

MIT