jsontools

Most JSON validators tell you there's an error at position 4,213 and leave it there. jsontools.gg fixes it: trailing commas, comments, single quotes, Python's True/None, a reply wrapped in a ```json fence, a log line with a timestamp in front. It also lists each change with the line it was on, so you can check nothing important got guessed.

Once it parses, the same input is ready to format, minify or sort, to run a JSONPath query against, or to compare with another version. The diff ignores key order and whitespace, so a reformatted file doesn't light up as "everything changed".

It's quick on big files (a 10 MB file formats in about a quarter of a second in our tests), works offline once loaded, and there's no account.