Why this is safe

01Where your file stays

The tool comes to you

A typical online tool sends your file to someone else’s computer, processes it there and sends the result back. Here it is built the other way around: Only the tool comes from the server. Your file stays where it is.

02What is created in your browser

The document is created in your tab

Your browser has long been a full-fledged computer: It writes PDFs, processes images, encrypts files and typesets letters. It only needs the program code, and it gets that from here. This is how every tool works:

1. Your file or your entriesFile · form
2. In the memory of your browserArrayBuffer
3. The tool computespdf-lib · Canvas · WebCrypto
4. A new file is creatednew Blob()
5. You download itblob: address

This is created directly in your browser:

• PDFs
• Invoices
• Letters
• Images
• QR codes and barcodes
• ZIP archives
• Calendar files

1. No service that accepts filesbnkz.de consists of ready-made pages, style sheets and program code. There is no account, no database with your files or entries, and no program on the server that accepts files.
2. Nothing is left behindThe site stores nothing of yours in your browser: no cookie, no local storage, no database. If you want to keep details for next time, for example for the next invoice, you save them as a file yourself.

This design supports more than a hundred tools, most of them in German only so far. Text recognition from scans would need a server or a very large recognition model, so it is not offered here.

03What the browser forbids

The rule is written into every page

Every page comes with a Content Security Policy: a list of prohibitions that is enforced by your browser, not by the page. Even against my own code.

• connect-src 'none'No fetch, no XMLHttpRequest, no WebSocket, no EventSource, no sendBeacon. The usual ways to send data in the background are blocked, even to bnkz.de itself.
• script-src 'self'Only program code from here. No outside script, no ad code, no tracking script from a third party.
• img-src 'self' blob: data:Images only from here or from the memory of your browser. That way the preview shows your own file without sending it anywhere. No tracking pixel from a third party either.
• form-actionForms do not send anywhere. The only exception is the “Suggest a tool” form, and that sends only to bnkz.de.

The rule blocks the usual ways, not every conceivable one. In the detailed explanation (in German), I list honestly which ways stay open. You can find the line itself by right-clicking the page and choosing “View page source”. It is right at the top, in the head.

04If you do send something

Only the “Suggest a tool” form

05Check it yourself

Four steps, two minutes

1. Press F12In Chrome, Edge and Firefox this opens the developer tools. On a Mac: Cmd + Option + I.
2. Go to “Network”This tab lists the requests this page makes, as long as the tab is open. Leave it open.
3. Use a toolDrag a PDF in, merge it, download the result.
4. Look at the listYour file is not in it. Apart from the page itself you only see an anonymous page counter without a cookie (p.php). Details are in the privacy policy. Tip: Type method:POST into the filter field, and the list stays empty.