1. Introduction: The Mystery of the Percent Sign You have likely seen a URL that looks like a chaotic mess of symbols. Instead of clear words, you see strings like Hello%20World , name%3DJohn , or even %E2%98%BA . This is Encoded text. It is the language web browsers use to talk to servers securely. While it is perfect for computers, it is completely unreadable for humans. If you are a marketer tracking a campaign, a developer debugging a script, or just a user trying to figure out where a strange link leads, you need to turn that mess back into plain English. This is where the URL Decoder comes in. It is a simple but powerful translation tool. It takes the "computer-safe" format (filled with percents and numbers) and restores it to the original "human-readable" format. It turns %20 back into a space, %40 back into an @ symbol, and %3F back into a question mark. In this guide, we will explore why URLs get scrambled in the first place, how the decoding math works...