How it works

Every tool on this site runs in your browser. When you add a file, your browser reads it from your device and processes it there. The file is not uploaded to our server or to anyone else's.

What happens when you use a tool

1. Your browser downloads the page and the tool's code from this site, like any web page.
2. You choose a file. Your browser reads it into memory on your device.
3. The tool's code processes the file on your device, usually in a background thread so the page stays responsive.
4. The result is created on your device. When you click Download, your browser saves it straight from memory.

Because the work happens on your device, speed depends on your computer or phone, and very large files can run into your browser's memory limits. The tools tell you when that happens.

Check it yourself

You do not have to take our word for it. Your browser's developer tools list every request a page makes. It takes about a minute:

1. Open a tool, for example SHA-256 checksum.
2. Open the developer tools. On Windows and Linux press F12 or Ctrl+Shift+I. On a Mac press Cmd+Option+I. In Safari, first turn on Show features for web developers under Settings › Advanced.
3. Select the Network tab. Click the clear button (a circle with a line through it) so the list is empty.
4. Add a file to the tool and wait until the result appears.
5. Look at the rows that appeared. You may see the tool's code being loaded from this site, such as files ending in .js. You will not see a request that sends your file.

What to look for

• Method. Uploads are almost always POST or PUT requests. Right-click the column headers and turn on Method: every request should be GET.
• Domain. Turn on the Domain column. Every request should go to this site.
• Size. No request should be anywhere near the size of your file. You can click any row and open its Payload or Request section to see exactly what was sent.

What the site loads

At the moment the site only loads files from its own address: the pages, styles, scripts, fonts and the data files the PDF tools need. It does not load anything from other companies, it does not set cookies and it does not use analytics.

Working offline

After you have used a tool once, your browser keeps a copy of it, so it also works without an internet connection. Try it: use a tool, switch off Wi-Fi or mobile data, reload the page and use it again. The copy holds only the site's own pages and code, never your files.

We plan to pay for the site with ads in the future. Ads are loaded from other companies, so you would see those requests in the network tab. Before that happens we will update this page and the privacy policy. The tools themselves will still not upload your files.