Paste broken JSON — with trailing commas, single quotes, unquoted keys, or comments — and the tool fixes it into valid JSON.
Trailing commas, single-quoted strings, unquoted object keys, comments, and other JSON5-tolerated syntax are all repaired into strict JSON.
Your input is parsed with the JSON5 parser (which is lenient) and re-serialized with strict JSON.stringify, producing valid JSON.
If the input is too broken for even the lenient JSON5 parser (e.g. missing brackets or mismatched quotes), it reports the parse error instead of guessing.