Free PDF tools that don't upload your files

What happens to a file you upload

When an online converter uploads your PDF, a copy of the document travels to a company's computers and is stored there while it's worked on - and usually for some time afterwards, often an hour or more, sometimes longer. Most services describe this in their privacy policies and delete files on a schedule, and many are careful. But for that time, your document exists on hardware you don't control, under the company's security and the laws of wherever its servers are.

For a recipe or a flyer that hardly matters. For the documents people most often need to merge, compress or convert - passports, bank statements, payslips, contracts, medical letters, exam certificates - it's worth asking whether the upload is necessary at all.

How a PDF tool can work without uploading

Modern browsers are powerful enough to read, change and write PDFs and images on their own. A browser-based tool sends you the program instead of asking you to send the document: the web page contains the code that merges, splits or compresses, and that code runs on your device.

1. You open the page; your browser downloads the tool's code, like any web page.
2. You choose a file; the browser reads it from your disk into memory. Nothing is sent.
3. The tool does the work in the background on your device, while the page stays responsive.
4. The result is handed straight to you as a download. When you press Start over or close the tab, the memory is cleared.

On SentrueFile, each page also carries a security policy that only allows it to talk to its own website, so it cannot send data to anyone else. The only things the site sends home are anonymous daily counts - which pages are viewed and whether a tool run worked - with no cookies, no IP addresses and nothing from your files. Browsers set to Do Not Track or Global Privacy Control send nothing at all.

How to check that a tool really doesn't upload

You don't have to take a website's word for it. Two simple tests:

• The offline test. Open the tool, wait for the page to load, then turn off Wi-Fi and mobile data (or switch on airplane mode). Now use the tool. If it still produces your file, the work happened on your device - an upload-based service can't do anything without a connection. SentrueFile's tools pass this test.
• The network test (on a computer). Open your browser's developer tools (F12, or right-click and Inspect), go to the Network tab, then use the tool. Upload-based services show a large request carrying your file. A browser-based tool shows no request containing your document.

Also read the privacy policy for plain statements rather than vague ones. SentrueFile's privacy policy says exactly what is and isn't collected.

What you can do without uploading

Everything below runs in your browser on SentrueFile, free and without an account:

• Merge PDF - combine up to 20 PDFs in the order you choose.
• Split PDF - extract pages or cut a PDF into separate files.
• Compress PDF - shrink scans and photo-heavy PDFs, or aim for a size such as 1 MB.
• Organize PDF and Rotate PDF - reorder, turn and delete pages.
• Add Page Numbers - number pages at the top or bottom.
• JPG to PDF and Scan to PDF - turn photos and paper into PDFs.
• PDF to JPG - save PDF pages as JPG or PNG images.
• Compress Image, Resize Image and Convert Image - get photos to the size, dimensions and format a form asks for.

The trade-offs of browser-based tools

Doing the work on your device is private and fast, but it has honest limits:

• Your device does the work. Very large files - a 300-page scan, or 20 high-resolution photos - take longer on an older phone and can run out of memory. A computer copes better, and lower quality settings help.
• Some formats aren't supported yet, such as iPhone HEIC photos and password-protected PDFs.
• Nothing is stored for you. There's no account or online folder; close the tab and the work is gone. Download your result before you leave.

For most everyday jobs - an application pack, a statement for a visa, a photo under 100 KB - none of these get in the way, and you skip both the upload wait and the question of where your document ended up.

Using browser-based PDF tools on a phone

No app is needed: the tools run in the phone's browser. Files open from your Files app or gallery, and results save back to your phone. Once you've opened a tool, its page keeps working even with a weak or no connection - handy in an office or exam hall with poor signal.

Tip: add sentruefile.com to your home screen from the browser menu. It then opens like an app, straight to the tools.

Questions to ask any online PDF tool

Before you hand a personal document to any website, a minute with these questions tells you most of what you need to know:

• Does the file leave my device? If the tool can't work offline, it almost certainly uploads.
• If it uploads, for how long is the file kept, and where? Look for a specific time and a named country, not just secure servers.
• Do I need an account? Sign-up walls often exist to collect email addresses rather than to protect your files.
• Is there a watermark or a page limit on the free version? Many free tools only let you try before you pay.
• Who runs it? A real company name and contact details on the site are a good sign; an anonymous site is not.

SentrueFile answers them simply: files never leave your device, there is no account, no watermark and no page limit, and the site is run by Sentrue Labs, whose contact details are on the contact page.