LightLine

A fast, lightweight code editor for Windows, written in Rust.

LightLine is a code editor that feels like VS Code but starts fast and stays light. It's a single portable .exe: no installer, no Electron, no admin rights. It draws its own window straight through Windows, so it uses little memory and keeps typing and scrolling smooth: in our tests it starts in under a tenth of a second, a keystroke reaches the screen in about 3 ms, and LightLine idling in the background doesn't wake up at all.

• Smart editing: syntax colors, code folding, bracket matching, find and replace, multiple cursors, word wrap, and a split editor.
• Unsaved-work recovery: periodic local checkpoints for modified files and untitled text, with a Restore/Discard choice after restarting. If LightLine ever crashes, it saves your unsaved work first. Cursor movement and deletion preserve combined characters and joined emoji.
• Stays in step with your files: files changed by another program reload by themselves; if you have unsaved edits, saving asks whether to keep your version or reload.
• Language support: errors as you type and a Problems panel, completions with fill-in arguments, parameter hints, inline type hints, highlighted uses of the name at the caret, go to definition and to symbols in the file or the whole project, rename across files, quick fixes, organize imports, and hover docs for Rust, Python, C/C++, JavaScript/TypeScript and Go, through their language servers.
• Run and debug: run Python, C/C++, JavaScript, TypeScript, Go or Rust with one key, and debug Rust and Python with breakpoints, stepping, variables and a Debug Console to evaluate expressions.
• Saved Run configurations: choose an entry file or command, arguments, environment variables and working directory in a panel that follows LightLine's theme. Each workspace remembers its configurations and selected default.
• Git built in: see changed lines in the margin, then stage, commit, push and review diffs without leaving the editor.
• Terminal: PowerShell, Command Prompt, Git Bash or WSL, in tabs.
• Markdown preview: see your README rendered beside the file as you type.
• Private AI Assistant (optional): ask about your code using a model on your own PC through Ollama. Off until you turn it on.
• Themes and icons: install color and icon themes from the Zed extension registry.
• Picks up where you left off: your folder, tabs and cursor positions come back when you reopen it.

1. Download lightline.exe from the latest release. It needs Windows 10 or 11. On a Windows on ARM PC, such as a Snapdragon laptop, download lightline-arm64.exe instead.
2. Double-click it. That's it; there's nothing to install.

Or install it with Scoop, which also keeps it up to date:

scoop bucket add lightline https://github.com/mehmoodulhaq570/LightLine
scoop install lightline

Update with scoop update lightline. Scoop adds LightLine to the Start menu and lets you run lightline from any terminal.

LightLine isn't code-signed yet, so Windows may show "Windows protected your PC" the first time. Click More info, then Run anyway. To check your download is genuine first, compare it with the release's SHA256SUMS.txt (how to).

Build it yourself (needs Rust):

git clone https://github.com/mehmoodulhaq570/LightLine.git
cd LightLine
cargo run --release

See the User Guide for every shortcut and setting, and how to set up Rust, Python, debugging, formatting and the AI Assistant.

Click Run or press Ctrl+Shift+R. No runner extension is needed; install the language's runtime or compiler first. JavaScript uses Node.js, TypeScript/JSX/TSX uses tsx, Go runs a package or standalone file, and Rust uses Cargo or rustc. Python uses the selected interpreter, and C/C++ uses GCC or Clang. JavaScript/TypeScript projects use their start or dev script when one is available. Programs run in Output, accept keyboard input, and retain their output and exit status. Use Stop Running Program in the Command Palette to stop a run.

Open ... → Run Configurations... in the editor, or Run: Configure / Select Saved Configuration in the Command Palette, to customize a run. Click New, fill in the fields, then Save & Select. Arguments use one line per argument; environment variables use one NAME=value per line. Paths are relative to the workspace. Automatic restores language detection.

The dropdown beside Run shows the selected configuration and switches between saved configurations and Automatic without opening the full panel. Choose Configure... to edit configurations. Missing runtimes or compilers show a LightLine error message with setup guidance; install the tool, add it to PATH, and restart the editor.

The panel uses LightLine's own controls, theme and fonts, with keyboard navigation, clipboard editing and scrolling in smaller windows. Configurations are saved in the workspace's .lightline/run.json; environment values apply only to the launched program and its children. See Direct language runners and Saved Run configurations for setup and shortcuts.

• User Guide: shortcuts, settings, language setup, AI Assistant, extensions
• Changelog: what's new in each release
• Contributing and Code of Conduct
• Architecture: how LightLine is built

LightLine collects no usage data and sends nothing on its own. It uses the network only when you:

• search for or install extensions;
• push, pull or fetch with Git;
• run Python: Install debugpy;
• allow web images in a Markdown preview;
• open a Python file without Pyright installed, when it asks before downloading Pyright.

LightLine stores preferences, caches and, if it ever crashes, a crash.log in %APPDATA%\LightLine; the log stays on your PC. It edits the files you open, and saves Run configurations in the workspace's .lightline/run.json. Standalone Rust runs and configured C/C++ runs create executables in a lightline-run folder in your temp directory; runtimes, compilers and project commands may create their own files or use the network. Python: Install debugpy also installs into your Python. To remove LightLine, delete lightline.exe and, if you like, %APPDATA%\LightLine.

Free code signing provided by SignPath.io, certificate by SignPath Foundation. Signing will start once the project is approved; until then, releases are unsigned.

Release builds of lightline.exe are built from this repository by the GitHub Actions release workflow. Only binaries built from this repository's source are signed.

MIT