Understanding URL Encoding: When and Why You Need It

If you’ve ever seen a URL filled with %20 or %3F, you’ve encountered URL encoding.

What is URL Encoding?

URLs can only be sent over the internet using the ASCII character-set. If a URL contains special characters outside of this set (like spaces, emojis, or foreign alphabets), they must be converted into a valid ASCII format. This is done by replacing the unsafe character with a % followed by two hexadecimal digits.

Reserved Characters

Certain characters like ?, &, and = have special meanings in URLs (query string delimiters). If your data actually contains an ampersand, you must encode it to %26 so the server doesn’t misinterpret it as a new parameter.

Encoding in JavaScript

JavaScript provides encodeURIComponent() to handle this automatically. If you need a quick way to encode or decode a string without opening the DevTools console, use our offline URL Encoder/Decoder.