Why do I see a malformed encoding error?

The input contains a percent sign that is not followed by two valid hex digits, so it is not valid percent-encoding. Check for stray % characters or truncated sequences.

Which mode should I use?

Component mode (decodeURIComponent) decodes every escape sequence and suits a single query value. Full-URL mode (decodeURI) leaves reserved characters like : / ? & # untouched.

Is my data uploaded anywhere?

No. Decoding runs entirely in your browser using built-in functions — nothing is sent to any server.

URL Decoder

Decode percent-encoded text and URLs back to readable form.

URL decoder

Turn percent-encoded text such as %20 and %2F back into readable characters. Use component mode (decodeURIComponent) to decode everything, or full-URL mode (decodeURI) to keep reserved URL characters intact.

It all happens in your browser with built-in functions — nothing is uploaded. To encode again, use the URL encoder.