URL Encoder / Decoder
Encode and decode URLs and query parameters. Supports encodeURIComponent for params and encodeURI for full URLs
How URL Encoding Works
URL encoding (also called 'percent-encoding') replaces special characters with %XX where XX is the hex code of the character. So a space becomes %20, & becomes %26, # becomes %23. RFC 3986 defines which characters need encoding. Letters, digits, and -_.~ are 'unreserved' and pass through unchanged.
Used everywhere URLs include user input. Search queries: 'hello world' becomes 'hello%20world' (or 'hello+world' in form data). Special characters in URLs: 'café' becomes 'caf%C3%A9' (UTF-8 bytes percent-encoded). Always encode untrusted input before placing it in a URL - failure to encode causes broken links and is a common source of XSS vulnerabilities.
Common URL Encodings
| Character | Encoded |
|---|---|
| space | %20 (or + in forms) |
| # | %23 |
| & | %26 |
| ? | %3F |
| / | %2F |
| : | %3A |
| = | %3D |
| @ | %40 |
| café (UTF-8) | caf%C3%A9 |
Frequently Asked Questions
Why are some characters encoded and others not?
Reserved characters (?, &, =, /, etc.) have special meaning in URLs - encoding preserves their literal value when used in data. Unreserved (letters, digits, -_.~) have no special URL meaning and stay as-is. The line is set by RFC 3986 spec; modern systems follow it strictly.
Is + the same as %20?
In query strings (form data after ?): yes, + represents space. In path components (before ?): no, + is literal +. Use %20 if you want a space in a path component. Most URL encoders default to + for query strings, %20 for paths.
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