About this tool
This JSON Formatter & Validator is a lightweight, privacy-first utility that runs entirely in your browser. It uses the native JavaScript JSON parser to both validate and transform JSON input. Common needs it solves include turning compressed JSON into readable, indented data for debugging, compacting human-readable JSON into a minimized representation for network transfer, and quickly surfacing syntax errors with actionable messages.
How to use
Start by pasting or typing the JSON into the input area. Use the Prettify button to format the JSON with consistent indentation and line breaks — useful for reading or code reviews. Use Minify to remove unnecessary whitespace for compact storage or transmission. The Validate control will attempt to parse your input and will show an error message with the parse exception if the JSON is invalid.
Benefits
Readable JSON speeds up debugging, makes diffs and PR reviews easier, and helps you find structural issues quickly. Validating before copying into code or sending to APIs reduces runtime errors. The client-side model minimizes latency: you get instant formatting with no network roundtrips.
Common edge cases
- Large JSON files (multi-MB) may be slow to parse in some browsers
- Trailing commas and comments are not valid JSON
- Binary data embedded as strings should be handled with the Base64 tool
FAQs
Q: Is my data sent to a server?
A: No — everything is processed locally in your browser.
Q: Can I format JSON automatically on paste?
A: Currently the tool uses manual controls to avoid unexpected transformations.