Privacy proof: check it yourself

Check it yourself

1. Test 1, airplane mode (phone or computer). Open a tool, for example Compress, and process a first file that doesn't matter: your browser then keeps what it needs for this tool.
2. Cut off every connection: airplane mode on a phone; Wi-Fi off and cable unplugged on a computer.
3. Now process your real document, then download the result. Everything works without the internet: no server is needed for the processing.
4. Test 2, the Network tab, in Chrome or Edge (computer). Open the tool, then press F12 or Ctrl+Shift+I (Cmd+Option+I on Mac) and choose the “Network” tab. Do this before choosing your file: the tab only records what happens while it is open.
5. In Firefox: press Ctrl+Shift+E (Cmd+Option+E on Mac) to open the Network tab directly.
6. In Safari (Mac): in Safari, Settings, Advanced, tick “Show features for web developers”. Then open the Web Inspector from the Develop menu and choose the Network tab.
7. Choose your file and start the processing. The list shows downloads coming from twodocument.com (pages, scripts, libraries, fonts) and, sometimes, a small request named “stat”. Click it: its content fits on one line, for example {"e":"traite","c":"compresser"}. That is the only thing sent, and your file is not in it. Lines starting with “blob:” or “data:” are data created on your device, not uploads.
8. To read the security rule: still in the Network tab, reload the page, click the first line (the page itself) and look for “content-security-policy” in the response headers. There you will see, among other things, connect-src 'self' blob: data:.

The page's security rule

Every TwoDocument page comes with a security rule, called Content-Security-Policy, which your browser enforces. It contains connect-src 'self': the page's programs can only exchange data with twodocument.com. If the page tried to send something to another site, through fetch, XMLHttpRequest or sendBeacon, the browser would block it. The programs themselves can only come from twodocument.com (script-src 'self').

So this rule prevents your file from leaving for a third-party site. To check that it does not go to twodocument.com either, look at the Network tab: the only things sent are described below, and none of them contains your document.

Everything that is sent

An anonymous counter. For every page viewed and every document processed or downloaded, the page sends twodocument.com/api/stat the type of event and the name of the tool, for example “one document compressed”. No cookie, no identifier. The counter records neither your IP address nor the name or content of your files.

Your e-mail address, only if you create an account or join the Premium waiting list. If you sign in with Google, Microsoft or Facebook, that service identifies you and then passes your address on to TwoDocument.

The file itself is never uploaded. As with any website, your browser downloads the pages and programs from our host, Cloudflare: these are downloads to your device, not uploads of your documents.

Offline, everything keeps working

Once a tool is open, your browser keeps what it needs: pages, programs, libraries. You can then switch off the internet: the tools already opened on this device keep working. A service that sent your files to a server could not work in airplane mode.

The files you create are kept for 7 days in “My files”, in your browser's storage, on your device. They are never transmitted. Clearing the site's data in your browser erases them.

The AI tools: Summarize and Translate

These two tools use the artificial intelligence built into Google Chrome. The first time, it is Chrome itself, not the page, that downloads its model. After that, according to Chrome's developer documentation, the model runs on your computer, offline, and no data is sent to Google or any third party when it is used. Your document is not sent to TwoDocument either.

Open-source libraries with public code

The work is done by well-known open-source libraries, served from twodocument.com in fixed versions. Their source code is public: anyone can check what they do.

The fonts used for conversions (Carlito, Caladea, Liberation Sans, Tinos, Cousine, Gelasio, Noto and others) are open source, under the SIL Open Font License.

The libraries used