URL Encoder/Decoder Online Free: Complete Guide to Percent-Encoding

If you've ever pasted a URL into a browser and seen %20 where a space should be, or watched an API call fail because a query parameter contained an ampersand, you've encountered URL encoding. Also known as percent-encoding, it's the mechanism that lets URLs carry special characters safely across the internet. In this comprehensive guide, we'll cover everything you need to know about URL encoding and decoding: the underlying standard (RFC 3986), how percent-encoding works character by character, the differences between reserved and unreserved characters, practical code examples in JavaScript and Python, a complete reference table of common encodings, and the most frequent mistakes developers make. Whether you need a quick URL encoder decoder online free tool or want to deeply understand the mechanics, this article has you covered. What Is URL Encoding (Percent-Encoding)? URL encoding — formally called percent-encoding — is the process of converting characters into a format that can be s