These are notes I wrote for the buttons on the home page, plus a longer JSON history because that question never goes away. Everything in the editor stays in your browser. Format is four-space stringify. Minify is the compact version. Auto Fix is jsonrepair.
Crockford, json.org, the RFCs, and why application/json is still everywhere. This is the long one.
Trailing commas, comments, keys without quotes. What Auto Fix will not guess for you.
Click a node, copy the value. Don’t turn it on for a 50 MB file unless you like waiting.