What Is URL Encoding?

URLs can only contain a limited set of ASCII characters. If you need to put spaces, special characters, or non-Latin text in a URL, they have to be "percent-encoded" — each byte gets converted to %XX format. A space becomes %20, an ampersand becomes %26, and so on. Decoding reverses the process back to the original characters.

When You'll Need It

API parameters — query string values with special characters need to be encoded
Redirect URLs — the target URL is often encoded and passed as a parameter
Debugging — logs full of %XX sequences are unreadable until you decode them
Form submissions — browsers encode form data automatically, but sometimes you need to do it manually