Files are processed in your browser, not uploaded. Privacy →
Deckle
Open a PDF
Skip to guide

Privacy

What browser-local PDF processing means

By DeckleUpdated

Browser-local PDF processing means the website sends its code to your browser, and that code reads and rewrites your PDF on your own device. The document's bytes are not sent to a server to be processed. In Deckle, every tool works this way: you choose a file, the browser tab does the work in background workers, and the result is saved back to your device. The site itself, its scripts and its processing engines still load over the internet.

Merge PDF

Three different privacy tasks

Password

Controls access

Metadata

Document properties

Redaction

Selected page content

Choose the change; inspect the saved copy

Conceptual comparison · access, properties and content require separate checks. No single task certifies complete privacy.

How it works, step by step

  1. The site loads. Your browser downloads Deckle's pages, scripts and fonts, like any website.
  2. A tool loads its engine. The first time you open some tools, the browser downloads the code they need, such as image decoders or the PDF reader.
  3. You choose a file. The browser reads it from your device. Deckle counts the pages and draws thumbnails.
  4. You run the tool. The work happens in background workers inside the tab, on your processor and memory.
  5. Deckle checks the result. It reopens the new file and measures it, on your device.
  6. You download it. The browser saves the result to your downloads folder.

At no step is the PDF sent to Deckle or to another service to be processed.

What travels over the network

Sent or received Contains your document?
Requests for pages, scripts, fonts and engines No
Ordinary web request details: IP address, browser, page requested No
The PDF you choose Not sent
Passwords typed into Password protect PDF or Unlock PDF Not sent
The result file Not sent; it is saved on your device

The servers that deliver the website receive the same request details any website receives. Those requests do not include your files, their contents or your passwords.

What is kept on your device

Open documents and the results you create are kept in your browser's private storage for this site, so a reload or a closed tab can come back to the same work. Other websites cannot read that storage. Closing a document removes it, and clearing the site's data in your browser settings removes everything Deckle has stored. See browser storage vs downloaded files.

How to check it yourself

You do not have to take a privacy statement on trust. Any desktop browser can show what a page sends.

  1. Open Deckle and open a tool, such as Merge PDFs.
  2. Open the browser's developer tools (F12 on Windows, Option-Command-I on a Mac in Chrome, Edge or Firefox; Safari needs its Develop menu turned on first) and choose the Network tab.
  3. Clear the list, then add your PDF and run the tool.
  4. Look at the requests and their sizes. Script, font and engine files are the site loading. An upload would appear as an outgoing request roughly the size of your PDF.

Run this with an ordinary test file rather than a confidential one.

What local processing does not cover

  • The contents of the file. A PDF you send can still carry an author name, attachments, comments or hidden text. Clean it with Remove PDF metadata first.
  • Your device and browser profile. Anyone with access to them can reach what is stored for the site. On a shared computer, close your documents when you finish.
  • Browser extensions. Extensions you install can read the pages you visit. That is outside any website's control.
  • Where you send the result. Once the file is emailed or uploaded somewhere else, that service's rules apply.

Trade-offs of local processing

Because the work runs on your device, speed and the largest file you can handle depend on its memory and processor. Very large PDFs and high-resolution image exports take longer on a phone than on a desktop. Some tools state limits next to their controls, for example the largest image size a device can convert. In return, nothing waits on an upload, and there is no server copy to delete afterwards.

Tips

  • Use a current browser. Deckle needs a current version of Chrome, Edge, Firefox or Safari.
  • Download results you want to keep. Browser storage is a convenience, not a backup.
  • Treat "browser-based" claims carefully elsewhere. Some sites run in the browser but still upload the file. The network check above tells you which.
  • Clean before sending. Local processing protects the file while you work on it, not after it leaves your device.

Frequently asked questions

If processing is local, why does Deckle need the internet?

To load the website and the engines each tool uses. Your document is not part of those requests.

Can Deckle see my files?

No. The file is read and processed by code running in your browser, and its bytes are not sent to Deckle's servers.

Does closing the tab delete my files?

Not immediately. Open documents stay in the site's browser storage so you can return to them. Close the document in Deckle, or clear the site's data, to remove it.

Is local processing the same as offline?

No. The site has to load over the internet. Local processing describes where your document is handled, not whether you are connected.

Related tools

Sources