URL Encode / Decode

Percent-encode or decode text and URLs: component vs. full-URL vs. form rules, with the changed characters highlighted. Runs in your browser.

URLs may only contain a small set of ASCII characters, so everything else (spaces, &, accented letters, emoji) is written as % and two hex digits per UTF-8 byte. Which characters get encoded depends on what you're building: a single query value or path segment must escape / ? & = and # (encodeURIComponent), while encoding a whole URL must keep them (encodeURI). Form posts turn spaces into +. Getting this wrong is the classic cause of broken links, double-encoded %2520 and "invalid signature" errors on signed URLs.