Best Private PDF Viewers: Keep Your Reading Habits Secret
Looking for a PDF viewer that doesn't track you? Here are the best privacy-focused PDF readers that don't collect your data or history.
Every time you open a PDF in most readers, something happens in the background that you don't see. Your reading habits get logged. Your document titles get sent to servers. Your usage data gets collected, analyzed, and sometimes sold.
It doesn't have to be that way. There are PDF readers out there that respect your privacy and don't treat your document activity as a data collection opportunity.
This guide covers the best privacy-focused PDF viewers and what makes them different from the mainstream options.
What Makes a PDF Viewer Private?
Before we get to the list, let's talk about what "private" actually means for a PDF viewer:
No Data Collection
The app shouldn't send your document titles, reading patterns, or any metadata to external servers. Some readers "phone home" every time you open a file, and that's a problem.
No Account Required
You shouldn't need to create an account just to open a PDF. Account-based systems can link your reading activity to your identity, defeating the purpose of privacy.
Local Processing
The PDF should open and render on your device, not in the cloud. Cloud-based viewers technically see everything you upload.
No History or Telemetry
The app shouldn't track which PDFs you've opened, when you opened them, or keep a record of your reading history.
The Best Privacy-Focused PDF Viewers
1. Sumatra PDF — Best Overall
Sumatra PDF is a free, open-source PDF reader for Windows that doesn't collect any data. It's lightweight, fast, and does one thing well: it opens PDFs without any fuss.
Platform: Windows
Price: Free, open source
Privacy features:
- No internet connection required
- No telemetry or data collection
- No account needed
- Open source — anyone can verify the code
Sumatra is minimal by design. It doesn't have advanced annotation features, but if you just need to read PDFs privately, it's excellent.
2. Firefox (PDF.js) — Best for Browser Viewing
Firefox has a built-in PDF viewer that processes PDFs locally using PDF.js. Your PDF never leaves your browser, and Firefox itself is pretty privacy-respecting.
Platform: Windows, Mac, Linux
Price: Free
Privacy features:
- PDFs render locally in the browser
- No data sent to Mozilla
- Enhanced tracking protection available
- No account required
Configure Firefox to always use its built-in viewer instead of Chrome or Edge's viewers for better privacy.
3. Apple Preview — Best for Mac Users
If you use a Mac, Preview is already installed and it's actually quite private. Apple doesn't collect data on your PDF reading habits through Preview.
Platform: macOS, iOS
Price: Free (comes with macOS)
Privacy features:
- No account required
- Local processing only
- Apple doesn't track document usage
- Works offline
Preview also has basic annotation tools if you need to highlight or add notes.
4. Okular — Best for Linux
Okular is KDE's document viewer and one of the most feature-rich options for Linux users. It's free and open source with no tracking.
Platform: Linux, Windows
Price: Free, open source
Privacy features:
- Open source — no hidden data collection
- Works completely offline
- No account or registration
- No telemetry by default
Okular also supports annotations and has more features than most privacy-focused readers.
5. Microsoft Edge — Best Built-in Option for Windows
Microsoft Edge has improved significantly, and its built-in PDF viewer actually processes files locally. It's not as private as the options above, but it's better than Adobe.
Platform: Windows
Price: Free (comes with Windows)
Privacy features:
- Local PDF rendering
- No Microsoft account required to view PDFs
- You can disable "Improve Microsoft Edge" to reduce telemetry
Go to Edge settings → Privacy and turn off any optional data collection for the best experience.
6. PDF Viewer (Android) — Best Mobile Option
The PDF Viewer app by Mozilla is a simple, privacy-focused option for Android that doesn't collect your data.
Platform: Android
Price: Free
Privacy features:
- No tracking or analytics
- Local processing only
- Open source
- Minimal permissions
What About Adobe Acrobat Reader?
Adobe Acrobat Reader is the most popular PDF reader, but it's not the most private. It collects usage data, can show personalized ads, and requires an account for some features. If privacy matters to you, consider one of the alternatives above.
Online PDF Viewers: Privacy Risks
Using an online PDF viewer means uploading your document to their servers. Even if they say they delete it after viewing, you have no way to verify that. Avoid online viewers for sensitive documents.
If you must use an online tool, make sure it's a one-time view and don't upload anything sensitive.
Quick Comparison
| Viewer | Platform | Open Source | Account Required |
|---|---|---|---|
| Sumatra PDF | Windows | Yes | No |
| Firefox PDF.js | All | Yes | No |
| Apple Preview | Mac/iOS | No | No |
| Okular | Linux/Windows | Yes | No |
| Microsoft Edge | Windows | No | Optional |
Wrapping Up
You don't need to sacrifice privacy just to read a PDF. Whether you're on Windows, Mac, or Linux, there are solid options that don't track your reading habits. Sumatra PDF and Firefox's built-in viewer are the easiest recommendations for most people — they're free, private, and get the job done.
If you need more features like annotation or editing, consider using a privacy-focused tool just for viewing and keeping your editing separate.