How I Built a Privacy-First PDF Toolkit That Runs Entirely in the Browser

Most "free" PDF tools online have a dirty secret: they upload your files to their servers. Some keep them. Some scan them. Some sell the data.

I wanted to build something different — a PDF toolkit where files never leave the user's browser.

The result is FileFlex — a free, browser-based file toolkit.

The Problem with Existing Tools

Open any popular online PDF tool and watch the Network tab in DevTools. You'll see your file getting uploaded to their servers within seconds. Then you wait. Then you download.