Why does the page make any requests at all?

To load its own scripts and engines (from this domain) and to send tiny anonymous usage counters so we know which tools are used. You can block the counters; the tools still work.

Are my files cached in the browser?

Only when you chain tools ("continue with"), in a local cache that is cleared when the next tool reads it. Never on a server.

Can I use the site offline?

Yes, once a tool page has been opened: it is installable as an app and keeps working without a connection.

How to check that a tool does not upload your files

Updated October 29, 2026

Every file tool says it is secure. Some mean "we use HTTPS to upload your contract to our server and delete it in an hour"; others mean the file never leaves your computer. The difference matters for an ID scan, a medical report or a payslip, and you can check it in two minutes.

This guide shows the check and explains how this site is built so that the check always passes.

The two-minute check

Open the tool's page, press F12 (or Cmd+Option+I on a Mac) and go to the Network tab. Clear the list, then use the tool with a real file. Watch the requests: a tool that uploads shows a POST or PUT with a size close to your file's. A tool that works locally shows only small requests for its own scripts, or none.

Stricter: once the page has loaded, switch the browser to offline mode (Network tab, "Offline") and run the tool again. If it still works, the processing is local. This site's tools pass that test; the engines are downloaded once and cached.

What "in the browser" means here

The image and PDF engines (codecs, pdf-lib, Tesseract, the video codecs of the browser) run as WebAssembly in Web Workers on your device. The only requests the site makes are for its own files and small anonymous counters: which tool ran, how long, whether it succeeded, never the file, its name or its content.

No file name appears in a URL; the error reporting strips paths; there are no third-party scripts, no cookies on the tool pages, and the privacy page lists every column the server stores.

Things that are still your responsibility

A local tool cannot protect a file you then email in clear text, or a password you reuse. Watermark ID copies, compress before sending so you do not fall back on cloud links, and keep originals where you control them.

Tips

A page that works offline cannot be uploading.
Extensions can read any page; check the Network tab with extensions disabled if you are unsure.
Our e2e tests fail the build if any request carries file data; the test is public in the repository.

Questions

Why does the page make any requests at all?: To load its own scripts and engines (from this domain) and to send tiny anonymous usage counters so we know which tools are used. You can block the counters; the tools still work.
Are my files cached in the browser?: Only when you chain tools ("continue with"), in a local cache that is cleared when the next tool reads it. Never on a server.
Can I use the site offline?: Yes, once a tool page has been opened: it is installable as an app and keeps working without a connection.