Don't Trust Us — Verify It Yourself
Most PDF tools claim privacy but quietly upload your files. We give you the tools to prove PDFMint never sends a single byte of your document anywhere. It takes 60 seconds.
Privacy claims are cheap. Every online PDF tool says they ‘respect your privacy,’ but how would you know? Their privacy policy is just a text file on a website — you have no way to verify what actually happens when you upload a file. PDFMint is different. Because every free tool runs entirely inside your web browser, you can use a feature that's built into Chrome, Safari, Firefox, and Edge — the Network tab — to literally watch the network traffic while you process a PDF. If even one byte of your document leaves your computer, you will see it. Spoiler: you won't. This page walks you through exactly how to verify it. No technical background required — if you can right-click, you can prove this. We'll also explain why it works the way it does, and what to do if you spot something suspicious on any privacy-claiming PDF site (including ours).
How Browser-Based Processing Works
Before we get to the proof, here's a quick primer on what makes PDFMint structurally different from server-based competitors. Understanding this is what makes the verification meaningful.
Code Runs Locally
When you load PDFMint, your browser downloads the JavaScript and WebAssembly that contains all the PDF logic. Once loaded, that code runs on your CPU, not on our servers.
Files Stay In Memory
When you drop a PDF, the file is read directly into your browser's memory using the standard FileReader API. It never touches a network socket, never gets POSTed anywhere.
Output Is Local Too
The processed PDF is created in browser memory and downloaded via a local Blob URL. You could literally unplug your network cable and PDFMint would still work.
Verify It in 60 Seconds
Follow these steps to prove with your own eyes that PDFMint never uploads your files. Works on any modern desktop browser.
1. Open the DevTools Network Tab
On any PDFMint tool page (try /merge), right-click anywhere on the page and select ‘Inspect’ or press F12 (Cmd+Option+I on Mac). The Developer Tools panel will open. Click the ‘Network’ tab at the top of the panel.
2. Clear the Existing Requests
You'll see a list of network requests already loaded (the page assets, JavaScript, fonts, etc.). Click the circular ‘Clear’ icon (or press Ctrl+L / Cmd+K) to wipe the list. This gives you a clean slate so you can clearly see any new requests that happen next.
3. Drop In a PDF File
While the Network tab is open and watching, drag a PDF file into the upload area — or click to browse and select one. Choose a real document, ideally something with sensitive content, so the test is meaningful.
4. Run the Operation
Click the action button (Merge, Compress, Split, etc.) and let the operation complete. Keep your eyes on the Network tab the entire time. Watch carefully for any new entries appearing in the request list.
5. Read the Result
If PDFMint uploaded your file, you would see a POST request with your filename and a payload size matching your file. You won't. The Network tab will stay completely empty during processing — zero requests, zero bytes out. That's your proof: the file never left your machine.
Browser-Specific Instructions
The Network tab works the same way in every major browser, but the menus differ slightly. Here's the exact path for each:
Google Chrome / Microsoft Edge / Brave
Press F12 (or Cmd+Option+I on macOS). Click the ‘Network’ tab. To filter for uploads only, select ‘Fetch/XHR’ at the top. The ‘Preserve log’ checkbox keeps requests visible across navigations. Look for any rows with method ‘POST’ during processing — there will be none.
Safari (macOS)
First enable Develop menu: Safari → Settings → Advanced → check ‘Show features for web developers’. Then on the PDFMint page press Cmd+Option+I, click the ‘Network’ tab in the inspector. You can filter by ‘XHR’ to focus on data requests. Process a file and observe — the list stays empty.
Mozilla Firefox
Press F12 (or Cmd+Option+I on macOS). Click ‘Network’. Use the ‘XHR’ filter button. The ‘Persist Logs’ option in the settings cog keeps requests across reloads. Drop a PDF, run the tool, watch nothing happen.
What You Should See
Zero Network Requests During Processing
From the moment you drop your file until the download finishes, the Network tab should show no new entries — no POST requests, no uploads, no telemetry pings carrying your file. The size column will not show your file size going outbound.
Bonus: It Works Offline
For the ultimate test, load PDFMint with internet access, then turn on Airplane Mode (or disconnect Wi-Fi / Ethernet). Reload the tool page if you need to — actually, don't reload, just use the page that's already loaded. Drop a PDF and process it. It still works perfectly. A tool that processes files offline cannot possibly be uploading them.
Source Code Transparency
We don't ask you to take our word for any of this. The PDF processing logic uses well-known open-source libraries: pdf-lib, pdf.js, and pdfjs-dist — all of which run client-side by design. You can inspect them on npm and GitHub. In the DevTools ‘Sources’ tab, you can also browse the actual JavaScript files served by PDFMint. The function that handles your file (e.g. mergePdfs, compressPdf) is right there, and you can set a breakpoint on it to confirm it operates on the in-memory File object without ever calling fetch() or XMLHttpRequest with your data. If you find anything that contradicts our privacy claims, please report it to security@pdfmint.app. We will publicly disclose and fix the issue within 24 hours. Trust isn't a marketing slogan — it's something we earn by being verifiable.
Frequently Asked Questions
Why don't competitors offer this kind of verification?
Because they can't. Smallpdf, iLovePDF, Adobe Acrobat web tools, PDF24 online, and most others perform their PDF processing on server infrastructure. The moment you click ‘Compress’ or ‘Merge’, your file is HTTP POSTed to their backend. If you opened the Network tab and tried this on those sites, you'd immediately see a large outbound request containing your document — there is no way to hide that.
Are there any exceptions where PDFMint does upload files?
Yes, and we're upfront about it. A few advanced features — PDF to Word conversion, Office to PDF conversion, and OCR — require server-side processing because the underlying engines are not yet practical to run in a browser. These are clearly labeled with a ‘Server’ badge in our UI and are gated behind the Pro plan. For Pro server tools, files are transmitted over HTTPS, processed, and deleted immediately. All free tools (merge, split, compress, rotate, organize, annotate, jpg↔pdf, protect, unlock, watermark, redact, batch) run entirely in your browser with zero uploads.
Can the JavaScript code secretly upload my file?
It cannot do so without making a network request, and a network request always shows up in the Network tab. There is no way for a web page to send data over the network without the browser's own network stack — and the browser shows that activity to you. Even if the code were obfuscated, the actual outbound traffic would be visible. This is the fundamental security model of the web platform.
What about analytics or error tracking — doesn't that count?
We use Google Analytics 4 to count page views and feature usage. These requests are visible in the Network tab too — they appear as small calls to google-analytics.com, and they contain no information about your files (no filenames, no file contents, no metadata). They're triggered by page navigation, not by file processing. You can verify this by checking the request payloads. We do not use any error reporting service that captures user data.
What if I want even stronger guarantees?
Use PDFMint offline. Load any tool page, then disconnect from the internet entirely. Process your most sensitive PDFs with confidence — no request can possibly be made when there's no network. You can also save the page for offline use, or self-host the source. The tools will keep working forever, exactly as they did when you first loaded them.
Now You Know — Try It With Confidence
Privacy you can verify yourself. Drop a PDF and watch the Network tab.