URL Encoder
Percent-encode or decode URL components — instantly, client-side.
Component vs Full URI encoding
encodeURIComponent encodes everything except letters, digits, and - _ . ! ~ * ' ( ) — including ?, &, =, #, and /. Use it for query parameter values and path segments. encodeURI preserves those characters plus : / ? # [ ] @ ! $ & ' ( ) * + , ; = because they have meaning in a full URL. Use it when encoding a complete URL to make it safe for a header or attribute without breaking its structure.
When you need percent-encoding
Spaces, non-ASCII characters, and reserved symbols must be encoded before being placed in a URL. A space becomes %20 (or + in form-encoded contexts), é becomes %C3%A9, and & in a query value must be %26 or it will be parsed as a parameter separator. OAuth signatures, redirect_uri parameters, and search queries all require proper encoding — a single unencoded character can break the entire request.
Reading percent-encoded sequences
Each percent-encoded sequence is a % followed by two hexadecimal digits representing one byte of a UTF-8 encoded character. %20 is a space (byte 0x20), %2F is a slash (/), %3A is a colon (:). Multi-byte characters need multiple sequences: the euro sign € is %E2%82%AC (three bytes in UTF-8). The Decode mode here converts any valid percent-encoded string back to its original form.