About this tool
Paste raw JSON to pretty-print it with proper indentation, minify it for transport, or simply validate it. Errors are reported with the parser's exact message so you can find the missing comma or stray trailing bracket fast.
Because everything runs locally, this formatter is safe for API payloads containing tokens, customer records or anything else you should never paste into a tool that ships your data to a server. JSON (ECMA-404) is strict by design: keys must be double-quoted, trailing commas are invalid, and comments are not allowed — the most common reasons a “looks fine” payload fails validation.
How to use it
- Paste JSON into the input panel.
- Click Format for indented output or Minify for compact output.
- Fix any reported syntax error and re-run; copy the result.
Frequently asked questions
Why does my JSON fail with single quotes?
The JSON standard requires double quotes around keys and string values. Single quotes are valid in JavaScript object literals but not in JSON.
Are trailing commas allowed?
No. {"a":1,} is invalid JSON even though many programming languages tolerate the same pattern in source code.
Is my data sent anywhere?
No — parsing and formatting use your browser's built-in JSON engine. The payload never leaves your machine.