Filozy

Private by design

Which PDF tools don't upload your files?

More than you might expect, and some are already on your computer. They fall into four kinds: tools built into your operating system or browser, desktop applications, self-hosted software, and websites that do the work inside your browser. What they share is that the document is processed on hardware you control. Whichever you pick, test it — the test is at the end, and it takes thirty seconds.

By the Filozy team, with AI assistance Reviewed How we write and review

1. Already on your computer

Preview (macOS)
Merge files by dragging pages between sidebars, reorder, rotate and delete pages, annotate, fill forms, add a signature, and redact text with Tools → Redact. Entirely local.
Microsoft Edge's built-in PDF viewer (Windows)
Fill in forms, highlight, draw and add text. Useful on work computers where you cannot install anything, since Edge ships with Windows.
Firefox's built-in PDF viewer
Add text, drawings, highlights and images to a PDF, and fill forms, without leaving the browser or uploading the file.

Built-in viewers annotate and fill; they do not merge, compress, convert or redact (except Preview). For those, read on.

2. Desktop applications

PDFsam Basic — free, open source, Windows, macOS, Linux
Merge, split, rotate and extract pages, fully offline.
LibreOffice Draw — free, open source
Opens a PDF so you can change text boxes and images, then export it again. Layout can shift on complex documents.

The trade is installation — not possible on every work machine, and not something you want to do on a borrowed one.

3. Self-hosted

Stirling PDF — open source
A broad PDF toolkit you run on your own computer or server. Files are sent to that server, which is yours — the right answer for a team that wants shared tools without a third party, and more setup than an individual usually needs.

4. Websites that process in your browser

The newest kind, and the one that needs neither installation nor an upload: the page downloads its processing engine to your device and does the work there.

Filozy — free, no account, 39 tools
Merge, split, compress, convert to Word, redact, OCR, sign and more, all inside the tab. Needs a connection to load the page; the job itself does not use it. Honest limits: the code is closed source, and signatures are visual marks, not certificates.

Other sites make the same claim, and some honour it for most tools while sending one or two — commonly compression or Office conversion — to a server. We have not named them because we cannot verify them from here. You can, in half a minute. For the best-known upload-based services we did measure it — see the PDF upload test, with the method and raw data.

The test that settles it — for any tool on this page

  1. Open the tool, then developer tools (F12) → Network. Clear the list.
  2. Run a job. An upload appears as a request about the size of your file; a local tool shows nothing of the kind.
  3. For certainty, turn on airplane mode and run it again in the same tab. A local tool still works.
  4. Repeat for each tool you rely on — the claim is per tool, not per site.

That includes us. The verification page walks through it on Filozy, and are online PDF tools safe? explains when uploading is perfectly fine anyway.

Common questions

Which PDF tools do not upload your files?
Tools that process the file on your own device. Some are already installed: macOS Preview can merge, reorder, rotate, sign and redact PDFs, and the PDF viewers built into Microsoft Edge and Firefox can fill forms and add text, drawings and highlights. Free desktop applications such as PDFsam Basic and LibreOffice Draw work offline. Stirling PDF can be self-hosted so files go only to your own server. And browser-based sites such as Filozy run the processing inside the browser tab, so nothing is installed and nothing is uploaded.
How do I know a PDF website really does not upload my file?
Test it rather than trusting the claim. Open developer tools with F12, select the Network tab, clear it and run a job; an upload shows as a request about the size of your file. Then load the tool, turn on airplane mode and run it again in the same tab: a tool that processes locally still works. Check each tool you use, not just the site, because some sites process simple tasks locally and send compression or Office conversions to a server.
Is there a free PDF editor that works without uploading?
Yes. For annotating, filling forms and adding text, the PDF viewers in Microsoft Edge and Firefox and Preview on a Mac need no upload and no installation. For merging, splitting, compressing, converting and redacting in a browser without uploading, Filozy offers 39 free tools with no account. For fully offline work on any operating system, PDFsam Basic handles merging and splitting.
Are browser-based PDF tools as capable as upload-based ones?
For most everyday jobs, yes — merging, splitting, rotating, compressing, converting images, filling forms, signing and redacting all run well in a modern browser. The gaps are the heaviest jobs on the weakest devices: a very large file on an old phone may be slow, because your device does the work instead of a server. That is the trade for the file never leaving it.