How It Works

This tool parses, validates, and reformats JSON text — entirely inside your browser. No data is ever sent to a server.

What is JSON?

JSON (JavaScript Object Notation) is a lightweight, human-readable data interchange format. It supports six value types: string, number, boolean, null, array, and object. Because it maps directly to JavaScript data structures, it is the most widely used format for REST APIs and configuration files.

Implementation Details

The tool uses two standard JavaScript built-ins — no third-party libraries are involved:

• Parsing & validation: JSON.parse(input) — if the input is not valid JSON, the built-in parser throws a SyntaxError whose message is displayed as the error feedback. If parsing succeeds the JSON is considered valid.
• Formatting: JSON.stringify(parsed, null, 2) — re-serialises the parsed value with 2-space indentation, producing consistently pretty-printed output regardless of the original whitespace or key ordering.
• Minification: JSON.stringify(parsed, null, 0) — re-serialises with no extra whitespace, producing the most compact valid JSON string.

Because the round-trip goes through JSON.parse → JSON.stringify, the formatter also normalises the data: duplicate keys are deduplicated and certain non-standard values (e.g. undefined, functions) are stripped.

Privacy

All processing happens locally in your browser tab. JSON payloads — which may contain sensitive business data — never leave your device.