QR64Code validates data with `JSON.parse` and reports the parse error as clearly as the browser allows. Valid JSON can be formatted with two or four spaces, or minified to one line.
What changed in this update?
The tool, explanation, limits, sources, and accessible form flow were reviewed together.
How to use it
- 1
Paste JSON into the input field.
- 2
Choose Validate, 2 spaces, 4 spaces, or Minify.
- 3
Copy the valid result or download it as a file.
Limits and security notes
JSON does not support comments, trailing commas, `undefined`, or `NaN`. Browser memory can be a limit for very large documents.
Comparison
| Format | Comments | Trailing commas |
|---|---|---|
| JSON | No | No |
| JSON5 | Yes | Yes |
| JavaScript object | Possible | Possible |
Frequently asked questions
Why is my JSON invalid?
Common causes are single quotes, a trailing comma, or an unquoted key.
Will key order change?
The tool does not alter values, but JavaScript serialization rules can affect visible key order.
Is data sent to a server?
JSON input is processed in the browser and is not sent to QR64Code servers.