DePDF: A Secure, Client-Side PDF Unlocker

September 10, 2025

Have you ever been stuck with a PDF that’s locked behind a password you already know but don’t want to type in every time? That’s the problem I wanted to solve with DePDF — a simple, privacy-focused tool to remove passwords from your own PDF files.


Why I Built It

Most “unlock PDF” tools on the web require you to upload your document to a third-party server. That’s a huge red flag for anything personal, confidential, or business-related. I wanted a solution that:

  • Runs entirely in the browser
  • Never uploads or stores files
  • Feels fast and lightweight

That’s exactly what DePDF does.


How It Works

At the heart of DePDF is QPDF — a powerful PDF manipulation library. I compiled it to WebAssembly (WASM), which means it can run safely and efficiently right inside your browser.

Here’s the flow:

  1. You drop a locked PDF into the app and enter the password.
  2. QPDF runs locally in your browser (via WASM) to decrypt the file.
  3. The unlocked PDF is instantly downloaded back to your device.

No uploads. No server in the middle. 100% client-side.


Security by Design

Privacy and security were the main design goals:

  • Client-side only — nothing leaves your device.
  • No tracking or analytics beyond basic usage stats.
  • Open standards — QPDF is a battle-tested open-source library.

This makes DePDF a tool you can trust for sensitive documents.


Try It Yourself

You can try DePDF here: https://depdf.co

It’s completely free, works in any modern browser, and keeps your files safe.

Manav Majithia