Question 1

Are my files safe and private?

Accepted Answer

Absolutely. This is the most important feature of ZentoPDF. All processing happens 100% locally in your web browser. Your files are never uploaded to any server, which means we—or anyone else—can never see them. Your privacy is guaranteed.

Question 2

Is ZentoPDF really free? What's the catch?

Accepted Answer

Yes, it's completely free, and there's no catch. There are no hidden fees, no subscription plans, no usage limits, and no premium-only features. We believe essential tools should be accessible to everyone.

Question 3

Do I need an internet connection to use the tools?

Accepted Answer

After you load the website for the first time, most tools will work completely offline! Because all the processing libraries are loaded into your browser, you can disconnect from the internet and continue to merge, split, compress, and edit your PDFs securely. Some niche tools that require external data (like Markdown to PDF with web images) may need a connection.

Question 4

Are there any file size or usage limitations?

Accepted Answer

No, we do not impose any artificial limits on file size, the number of files, or how many times you can use a tool. The only practical limitation is the processing power and memory of your own computer, as very large or complex files may take longer to process.

Question 5

Why did my PDF fail to process?

Accepted Answer

Failures are rare but can happen for a few reasons: The PDF might be corrupted or not compliant with standard specifications. The file could be encrypted with a password you don't have. Please use our Decrypt tool first. The file might be a special XFA or dynamic form-based PDF, which some of our tools cannot process.

Question 6

Do you track my activity on ZentoPDF?

Accepted Answer

We care about your privacy. ZentoPDF does not track personal information. We use Simple Analytics solely to see anonymous visit counts. This means we can know how many users visit our site, but we never know who you are. Simple Analytics is fully GDPR-compliant and respects your privacy.

Question 7

What technology does ZentoPDF use?

Accepted Answer

ZentoPDF is built on the power of modern web technologies. We primarily use JavaScript libraries like PDF-lib.js and PDFKit.js that are compiled to run efficiently in your browser via WebAssembly. This allows for powerful, server-like processing without your data ever leaving your machine.

Frequently Asked Questions