Make any window on Windows see-through — per app, with a slider.
Transparency App is a lightweight tray utility that lets you set the opacity of other applications' windows. Want your code editor at 90% so you can read a video behind it, keep a chat window ghosted over your work, or dim everything except what you're focused on? Add a rule, drag a slider, done. Rules keep working for windows you open later, and the app sits quietly in your system tray.
- 🪟 Per-app transparency rules — match by window title or by application, each with its own opacity.
- 🎯 Pick a window — click one of your open windows instead of guessing its exact title.
- 🎚️ Quick shades — one-tap 25 / 50 / 75 / 100 %.
- 🗂️ Presets — save rule sets and switch between them (Work, Gaming, …).
- 🫥 Focus mode — dim every window except the one you're using; it follows your focus automatically.
- 🌒 Screen dimmer — a soft, click-through overlay across all monitors.
- ⌨️ Global hotkeys — toggle transparency/focus, nudge opacity, or restore everything with one keystroke. Every shortcut is remappable in Settings.
- 🖱️ Per-rule click-through & always-on-top.
- 🚀 Run at startup, 💾 import/export settings, 🌗 dark/light theme, 🎨 seven accent colours.
- Download
TransparencyApp.exefrom the latest release. - Double-click it to run. That's it — no installer, no admin rights.
- (Optional) Turn on Settings → Start with Windows to launch at sign-in.
Windows SmartScreen may warn about a new unsigned app. Choose More info → Run anyway. The full source is in this repo and the executable is built in the open by GitHub Actions.
- Click ＋ Pick a window and choose an open window.
- Drag its Opacity slider down.
- Minimise to the tray — the rule keeps working in the background.
The full guide is in docs/USAGE.md.
All remappable in Settings → Keyboard shortcuts. Defaults:
| Shortcut | Action |
|---|---|
Ctrl+Alt+T |
Toggle all transparency |
Ctrl+Alt+F |
Toggle focus mode |
Ctrl+Alt+↑ / ↓ |
Focused window more / less opaque |
Ctrl+Alt+Home |
Restore every window (panic) |
Windows exposes per-window opacity through layered windows
(SetLayeredWindowAttributes). Transparency App watches the system for window
events (a window opening, showing, being renamed, or gaining focus) via
SetWinEventHook and applies your rules only when something actually changes —
so it costs almost nothing while idle, unlike a polling loop. A single worker
thread owns all the Win32 calls, every window's original state is recorded so
it can be restored exactly, and if the app is ever killed it cleans up on the
next launch.
Windows-only, Python 3.12:
python -m venv .venv
.venv\Scripts\activate
pip install -r requirements-dev.txt
python -m transparency_app # run from source
pyinstaller --clean --noconfirm TransparencyApp.spec # build the exeSee docs/BUILDING.md for the test suite, project layout, and release process.
Issues and pull requests are welcome. Please run the tests
(powershell -File scripts\run_tests.ps1) before opening a PR. Changes are
tracked in CHANGELOG.md.
Released under the MIT License.