Ulauncher — Fast Application Launcher for Linux

Introduction

Ulauncher is a lightweight application launcher for Linux that provides quick access to apps, files, bookmarks, and custom actions through a keyboard-driven search interface. It fills the same role as Spotlight on macOS or PowerToys Run on Windows.

What Ulauncher Does

• Searches and launches installed desktop applications with fuzzy matching
• Browses files and directories with real-time path completion
• Runs custom web searches and calculator expressions
• Extends functionality through a community extension ecosystem
• Supports custom shortcut keywords for frequently used actions

Architecture Overview

Ulauncher is built with Python and GTK, running as a persistent background process that listens for a global hotkey. On activation, it presents an overlay search bar that queries an indexed list of desktop entries, files, and extension results. Extensions communicate via a WebSocket-based API, allowing both Python and script-based extensions to provide search results asynchronously.

Self-Hosting & Configuration

• Install via PPA (Ubuntu), AUR (Arch), RPM, or from the GitHub releases
• Configure hotkey, theme, and behavior from the preferences window
• Extensions are installed by pasting their GitHub URL into the extension panel
• Custom user shortcuts can map keywords to URL patterns or shell commands
• Autostart is configurable via the desktop environment autostart mechanism

Key Features

• Fuzzy search with smart ranking that learns from usage patterns
• Extension API with 300+ community extensions for various services
• Customizable themes with CSS-based styling
• Custom shortcuts for parameterized commands and URL templates
• Low memory footprint with fast startup time

Comparison with Similar Tools

• Albert — C++/Qt-based launcher with similar features but heavier resource usage
• Rofi — powerful but primarily a window switcher/dmenu replacement with steeper configuration
• dmenu — minimal and composable but requires scripting for app-launcher functionality
• GNOME Shell search — built-in but limited extension support and not available on other desktop environments
• Flow Launcher (Windows) — similar concept but Windows-only

FAQ

Q: Which Linux desktop environments does Ulauncher support? A: It works on GNOME, KDE, XFCE, i3, Sway, and most X11 or Wayland-based desktops.

Q: Can I write my own extensions? A: Yes. Extensions are Python packages that implement the Ulauncher extension API. A project template is available in the documentation.

Q: Does it support Wayland? A: Yes, with caveats. The global hotkey works on most Wayland compositors but may require compositor-specific configuration on some.

Q: How much memory does it use? A: Ulauncher typically uses 30-60 MB of RAM while running in the background.

Sources

• https://github.com/Ulauncher/Ulauncher
• https://ulauncher.io