URL encoder & decoder

The URL encoder & decoder converts text to and from percent-encoding — the %XX escapes that let spaces, punctuation and non-ASCII characters travel inside a web address. Pick encode or decode, then the scope: component mode escapes every reserved character and is right for a single query-string value; full-URL mode leaves structural characters such as : / ? and # alone, so a whole URL can be encoded without breaking it. When decoding hits a malformed escape such as %ZZ, the tool says so instead of silently mangling the text.

Component mode escapes every reserved character — use it when the value is one piece of a URL, such as a query parameter. Full-URL mode leaves the structural characters : / ? # alone — use it when the input is already a complete URL.

The input contains a malformed % escape — %ZZ, or a stray % followed by fewer than two hex digits. The tool reports it rather than guessing.