Merge PDF Files

Combine multiple PDF files into a single document, right in your browser. Free, private, no upload, no size limits, no watermarks.

Drop your files here (.pdf)

🔒 Private by design: your files are processed locally in your browser and never uploaded to any server.

How to merge PDF files

  1. Drag and drop your PDF files into the box above, or click it to pick them.
  2. Check the file list — files are merged top to bottom.
  3. Click Merge PDFs and download the combined document.

That’s it. No account, no email, no upload progress bar — because there is no upload.

Why merge PDFs in the browser?

Most online PDF mergers send your documents to a server, process them there, and send the result back. That means your contracts, bank statements or medical records travel across the internet and sit, at least temporarily, on someone else’s machine.

SysFenix works differently. The merge runs locally in your browser using WebAssembly: the same technology that powers in-browser games and video editors. Your files are read directly from your device’s memory, combined there, and the result is saved back to your downloads folder. Nothing is transmitted, logged or stored.

This approach has practical benefits beyond privacy. There is no file size cap, because there is no server bill to protect. There is no queue, because you are not sharing a machine with other users. And it works even on a flaky connection, because after the page loads, the network is no longer needed.

Common uses

Frequently asked questions

Are my PDF files uploaded to a server?

No. The merge happens entirely inside your browser using WebAssembly. Your files never leave your device, which makes this tool safe for contracts, invoices and other sensitive documents.

Is there a file size or page limit?

There is no artificial limit. Because processing is local, the only practical limit is your device's memory. Merging documents with hundreds of pages works fine on a normal laptop or phone.

Will the merged PDF have a watermark?

No. The output is a clean PDF containing your pages in the order you added them — no watermarks, no branding, no account required.

In what order are the files merged?

Files are merged in the order they appear in the list, from top to bottom. Add them in the order you want them to appear in the final document.

Does this work on mobile?

Yes. The tool runs in any modern browser, including Safari on iOS and Chrome on Android.

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