JSON is the lingua franca of web APIs, configuration files, and data exchange — but servers usually send it minified into a single unreadable line. A JSON formatter (also called a beautifier or pretty-printer) adds indentation and line breaks so the structure becomes obvious: which objects contain which fields, where arrays begin and end, and where that missing comma broke everything.
This tool formats, validates, and minifies JSON entirely in your browser. If the input is invalid, you get the exact parser error so you can fix trailing commas, unquoted keys, or mismatched brackets quickly. Because nothing is uploaded, it is safe for API responses containing private data.
How to Use This Tool
- Paste your raw or minified JSON into the input box.
- Click Format for 2-space or 4-space indentation, or Minify to compress it.
- If the JSON is invalid, read the error message to find the exact problem.
- Copy the result with the copy button.
Frequently Asked Questions
What makes JSON invalid?
The most common errors are trailing commas after the last item, single quotes instead of double quotes, unquoted keys, and comments (standard JSON does not allow them). The validator pinpoints the first character where parsing failed.
What is the difference between formatting and minifying?
Formatting adds whitespace for human readability. Minifying removes every unnecessary space and line break to make the payload smaller for transmission — both represent exactly the same data.
Is it safe to paste API responses with sensitive data?
Yes. The formatting runs locally in your browser with JavaScript's built-in JSON parser. No data leaves your machine, unlike some online formatters that process JSON server-side.