DevTools Pro · 1 November 2026

Common JSON parse errors

The JSON formatter uses the browser's JSON.parse. When parsing fails, the page shows that SyntaxError message, including the position when the browser provides one. The text you paste stays in the browser.

Trailing commas

{ "name": "Ada", } is invalid. JSON does not allow a comma after the last property or array item.

Single quotes and unquoted keys

Keys and strings must use double quotes. { name: 'Ada' } is JavaScript, not JSON.

Comments

JSON has no // or /* */ comments. Remove them before formatting.

How to fix the error

The formatter reports the browser error and leaves the text unchanged. Fix the syntax at the reported position, then format or minify again. For an array of objects, the JSON to CSV converter uses the same JSON.parse rules.