JSON (JavaScript Object Notation) is the standard format for APIs, configuration files and data exchange. Machines are happy with a single long line of JSON, but people are not. Formatting adds indentation and line breaks so you can read the structure, while validation tells you exactly where a syntax error is.
How to format JSON online
- Open the JSON Formatter.
- Paste your JSON into the input box (or load a sample).
- Click Format. Valid JSON is pretty-printed with your chosen indentation.
- If the JSON is invalid, read the error message — it shows the line and position of the problem.
- Copy or download the formatted result.
The most common JSON errors
| Error | Wrong | Correct |
|---|---|---|
| Trailing comma | {"a": 1,} | {"a": 1} |
| Single quotes | {'a': 'b'} | {"a": "b"} |
| Unquoted keys | {a: 1} | {"a": 1} |
| Comments | // note | Not allowed in JSON |
| Undefined / NaN | {"a": undefined} | {"a": null} |
Other useful JSON tools
- JSON Validator – check syntax only.
- JSON Minifier – remove whitespace for smaller payloads.
- JSON Tree Viewer – explore large nested objects.
- JSON Diff – compare two JSON documents.
- JSON to CSV – open data in a spreadsheet.
Privacy tip
ToolsPoint's JSON tools run in your browser, but you should still remove secrets like API keys, tokens and passwords before pasting data into any website.
Try it now: JSON Formatter
Format and prettify JSON with validation. Free, fast and private.
Open JSON Formatter →