Developer Tools
JSON Formatter
Beautify JSON with two or four spaces, or a tab character. Paste your JSON, pick an indent style and format it in one click. Parse errors include the line and column so you can fix typos fast.
Your input is processed locally in your browser. It is not uploaded to Dueneo.
Loading JSON Formatter…
How to use
- 1
Paste your JSON
Drop raw JSON into the left-hand editor. The textarea preserves whitespace and never autosaves — your input stays in your browser tab.
- 2
Pick an indent style
Choose 2 spaces (the most common convention), 4 spaces for readability, or a tab character for compact editors.
- 3
Format and review
Click Format JSON. The pretty-printed result appears on the right; if your input is invalid you get the exact line and a snippet so you can fix it.
- 4
Copy or download
Use Copy to put the result on your clipboard, or Save to download it as formatted.json.
Common use cases
- Make a minified API response readable before debugging.
- Standardise indentation across a team before committing a config file.
- Validate that hand-written JSON has balanced braces and quotes.
- Prepare a JSON payload for a code review or documentation snippet.
Limitations
- Inputs larger than 1 MB are rejected to keep the tab responsive.
- Trailing commas are not valid JSON and will be flagged as errors.
- JSON with circular references cannot be serialised — this tool follows the standard
JSON.stringifybehaviour.