Transparency, by design
Privacy proof
Your files never leave your device. Here is how that works, how to check it yourself in a minute, and what our automated tests record for each release.
What happens to your files
- Your browser reads the file you choose into the page's memory. Nothing is sent anywhere to do that.
- The tool runs on your device, in your browser, using background workers. The engines it needs (for PDFs, images, passwords and OCR) are downloaded from this site like the page itself, and run locally.
- The result is made on your device and offered as a download from the page's memory (a blob: address), not from a server.
- There is no upload address. This site is only static files: its server can send them, and it refuses anything else. The page's security policy also stops it from connecting to any other site.
- Once a page has loaded, it keeps working with your internet connection turned off. That is the simplest proof.
Check it yourself
- Open a tool and wait until the badge at the top says “Offline ready”.
- Open your browser's developer tools on the Network tab (F12, or Ctrl+Shift+I; on a Mac, Cmd+Option+I). Or open “Network activity” at the bottom of the tool, which lists the same requests on the page.
- Turn off Wi-Fi or mobile data.
- Run the tool. It still works, and the Network tab shows no upload: every request is the app fetching its own files, and nothing is sent.
- Compare what you see with the capture from our tests, below.
The network activity list on each tool
Every tool page has a “Network activity” list that counts every request since the page opened and says whether any of them sent data. It combines your browser's own record of the page's requests with reports from this site's offline worker, which sees what the page and its background workers fetch.
It can't see everything. On a first visit, before offline mode is running, the background workers' requests aren't listed (the page's own are). The browser's own checks for app updates are never listed, and neither is anything a browser extension does. Your browser's developer tools show all of these.
Network captures from our tests
Before each release, automated tests run every tool flow in Chrome, Firefox, Safari (WebKit), and Chrome on Android (emulated), recording every request the browser makes from loading the page to downloading the result. A test fails if any request goes to another site, uses a method other than GET or HEAD, or carries a body.
Release 0.1.0, captured 2026-10-17: 4,970 requests in 48 recordings, none to another site, and none sent any data.
| Tool flow | Browsers | Requests | To other sites | Sent data |
|---|---|---|---|---|
| A typed signature and date send no file data or name anywhere | 4 | 43–46 | 0 | 0 |
| An uploaded signature photo is used without sending it anywhere | 4 | 39–43 | 0 | 0 |
| Compressing sends no file data anywhere | 3 | 67–321 | 0 | 0 |
| Converting images sends no file data anywhere | 3 | 63–69 | 0 | 0 |
| Crop, flatten and metadata send no file data or metadata anywhere | 4 | 90–95 | 0 | 0 |
| Editing text sends no file data or text anywhere | 4 | 36–41 | 0 | 0 |
| Making a searchable PDF sends no file data or words anywhere | 3 | 54–307 | 0 | 0 |
| Merging PDFs sends no file data anywhere | 4 | 32–35 | 0 | 0 |
| Page tools send no file data anywhere | 4 | 61–337 | 0 | 0 |
| Protecting and unlocking send no file data or passwords anywhere | 4 | 66–69 | 0 | 0 |
| Reading a scanned card in Mask Aadhaar sends no file data or numbers anywhere | 3 | 62–316 | 0 | 0 |
| Redacting and masking send no file data, words or numbers anywhere | 4 | 73–88 | 0 | 0 |
| Watermark and page numbers send no file data or logo anywhere | 4 | 61–317 | 0 | 0 |
Download the full capture for release 0.1.0 (JSON): every file each flow requested, with method and type. It holds no file contents, because no request carried any.
Sharing files to the app
Once Staydoc is installed, you can share PDFs and images to it from other apps. Your device hands them to the app's offline worker, which keeps them on the device until you choose a tool, then deletes them.
One case is different. If the offline worker isn't there, for example just after you clear the browser's data for this site, your browser would send a shared file to this site's server. The server refuses it, because it accepts no uploads, and keeps nothing, but the file would have left your device. After clearing site data, open the app once before sharing files to it.
What this can't cover
- Browser extensions can read any page you open, including this one. Use a browser profile without extensions for sensitive files.
- Files you download are saved by your browser to your device, where your own backups and sync apps may copy them.