SYNTHLUCIDA LEVEL is a free web-based spirit level and inclinometer. The app reads data from your phone's gyroscope and accelerometer (DeviceOrientation API) and converts it to a tilt angle in real time. It includes a Surface mode for two-axis leveling, an Angle / Tilt mode for measuring the slope of a single edge, and an optional flashlight feature. Everything runs directly in your browser, with no installation required.
The app doesn't collect or send any personal data to a server. Specifically:
The app requests access to your gyroscope and accelerometer (DeviceOrientation API) so it can display the device's tilt in real time — without this access the app can't function. For the flashlight feature, on some devices (Android/Chrome) the app requests camera access in order to turn on the camera flash; the camera's video feed is never displayed, stored, or sent anywhere — it's used solely to control the flash. Where turning on the flash isn't available (e.g. iPhone), the app instead just lights up the screen.
The app stores the following in your browser's localStorage (locally on your device, not on a server):
This data never leaves your browser, and the app has no access to it from anywhere else. You can remove it by clearing the site's data in your browser settings.
You can export your saved readings as a CSV file. The export is generated locally in your browser from the data stored in localStorage — the app never sends it anywhere on its own; the file downloads directly to your device.
The app loads fonts from Google Fonts (fonts.googleapis.com). Loading the page therefore sends a standard request to Google's servers, which is common practice for most sites using custom fonts. Aside from that, the app loads no other external scripts or tracking code.
If you run into a bug or have any question about privacy or how the app works, please reach out via the contact form on synthlucida.com. We'll do our best to sort it out quickly.