Privacy
Seratus is built so that your personal information never reaches us. There is no account, no server, no database on our end. This page explains where your data actually goes.
The short version: everything stays on your device. We collect nothing. We store nothing. We see nothing.
When you use Seratus, all your information (your name, dates, finances, health data, notes) is saved to your browser's localStorage. This is a storage area built into every modern browser that lives entirely on your device. It works like a file on your computer. It is not sent anywhere.
localStorage is sandboxed by origin: only Seratus can read Seratus's data. No other website you visit can access it. You can verify this yourself: Seratus is open source, and there is no code that transmits your data over a network.
A few honest caveats: localStorage is not encrypted on your device, so anyone with physical access to your computer and your browser profile could open it. Browser extensions with broad permissions can also read it. If either of those concern you, we recommend reviewing your installed extensions and using a device you control.
If you clear your browser data, your Seratus data clears with it. That's why we give you the option to export a backup file. That file also stays on your device. We never see it.
Seratus can import data from Apple Health, with support for Clue, Natural Cycles, Flo, and Seratus v1 coming soon. The same privacy guarantee applies to all of them.
You export your data from the source app directly to your device. You then open that file in the Seratus import tool. The file is read and converted entirely in your browser. Nothing is uploaded. Nothing is sent anywhere.
The result is a JSON file that downloads to your computer for you to review. You decide what to import and when. We never receive the original file, the converted file, or any of its contents.
Seratus uses no cookies, no analytics, no tracking scripts, no third-party services that collect data about you. There is nothing to opt out of.
The only external resource loaded on the landing page is the Google Fonts icon library (Material Symbols), which is used for icons. Google may log that request. If that concerns you, the app itself functions without it.
You can export your data as a JSON file at any time. This file contains everything you've entered. You can keep it, move it to another device, or import it back into Seratus. It is your filewe never see it or receive a copy.
Seratus is open source. You can read every line of code and verify these claims yourself. If you find something that contradicts what's written here, please open an issue on GitHub.
If you have any questions about privacy, you can reach out via GitHub.
Last updated: May 2026