JSON Formatter & Beautifier
Paste in JSON and this prettifies, minifies or validates it — with indentation you control, syntax highlighting, and error messages that actually tell you where the problem is in plain language. Your input is treated as plain text and never executed, and it all runs locally.
- 100% free
- Private & safe
- Runs in your browser
Why use JSON Formatter?
JSON Formatter is a quick, no-nonsense developer utility that runs entirely client-side, so your code and data never leave your machine.
- Runs instantly in your browser — nothing to install, nothing uploaded.
- Completely free, with no account, no watermarks and no usage limits.
- JSON (RFC 8259)
- Paste JSON, or load the example to see the format.
- Works on any device — desktop, tablet and phone — and is fully keyboard accessible.
What it can do — and its limits
- Validates JSON and pinpoints the line/character where parsing fails.
- Beautifies with 2-space, 4-space or tab indentation, or minifies to one line.
- Handles large documents and nested structures; syntax highlighting aids scanning.
- Parsing happens in your browser — your data isn't sent anywhere.
How to use JSON Formatter
- Paste JSON, or load the example to see the format.
- Choose indentation: 2 spaces, 4 spaces or tabs.
- Format to prettify, Minify to compact, or Validate to check correctness.
- Invalid JSON shows a clear message with the line and column of the error.
- Copy or download the result. Optionally sort object keys.
Examples
- Beautifying a minified API response to read it.
- Minifying a config file before embedding it.
Worked example
Input
{"name":"Ada","skills":["math","code"],"active":true}
Output
{ "name": "Ada", "skills": ["math", "code"], "active": true }
Minify reverses this back to a single compact line for transport.
Supported formats & limits
- JSON (RFC 8259)
Limitations
- Extremely large inputs are guarded to protect browser performance.
- Comments and trailing commas are not valid JSON and will be reported as errors.
Common problems & fixes
"Unexpected token" / trailing comma error.
JSON doesn't allow a comma after the last item in an object or array. Remove it.
Keys or strings use single quotes.
JSON requires double quotes around every key and string value.
Comments cause a parse error.
Standard JSON has no comments. Remove // or /* */ before parsing.
Sources & references
Last verified August 2026.
Frequently asked questions
Is my JSON sent to a server?
No. Parsing, formatting and validation all happen in your browser.
Is the input ever executed?
Never. Input is treated strictly as text and parsed safely — no eval is used.
Can it handle very large JSON?
It guards extremely large inputs to protect performance; for multi-megabyte files, format locally in an editor.