JSON Formatter Online
Paste JSON, get it beautified instantly — with syntax highlighting, a foldable tree view and the exact position of any error. Runs in your browser, nothing is uploaded.
Input
Output
About this tool
JSON is easy for machines to parse and painful for humans to read once it arrives minified from an API. This formatter re-indents any valid JSON document, highlights keys, strings and numbers, and points at the exact line and column when the syntax is broken. Switch the output to Tree when the document is deep enough that indentation alone stops helping — every object and array folds away. Minify is one click away when you need the compact form back.
How to use it
- 1Paste or type your JSON into the input panel on the left.
- 2Pick an indent size — 2 spaces, 4 spaces or a tab. Formatting happens as you type.
- 3Switch the output to Tree to fold nested objects, or press Copy to take the formatted text.
Frequently asked questions
›How do I collapse parts of a large JSON document?
Switch the output to Tree view. Every object and array becomes a foldable node showing its key count, so you can collapse the parts you do not care about and drill into the ones you do. Collapse all gives you the top level at a glance.
›What is JSON formatting?
Formatting (or beautifying) adds line breaks and indentation to JSON so the structure becomes readable. The data itself is unchanged — only the whitespace differs.
›What's the difference between beautify and minify?
Beautify adds indentation for humans; minify removes every optional space and newline to make the payload as small as possible for transfer. Both produce valid, identical JSON data.
›Is my data uploaded to a server?
No. The formatter runs entirely in your browser with JavaScript. Nothing you paste ever leaves your machine, which makes it safe for API keys, tokens and production payloads.
›Can I format large JSON files?
Yes. Files of several megabytes format in well under a second because the work happens locally. Very large documents are limited only by your browser memory.
›How do I format JSON in the terminal instead?
Pipe it through jq: cat data.json | jq . — or with Python: python -m json.tool data.json. Both give the same indented output as this tool.