JSON (JavaScript Object Notation) is the format APIs, apps and config files use to exchange data — but raw JSON is often a single unreadable line. A JSON formatter beautifies it with proper indentation and syntax highlighting, so you can actually read and debug it.
The free tool below formats, validates and minifies JSON instantly. Paste your code, get clean indented output with color-coded keys, strings and numbers, a collapsible tree view for deep structures, and exact line numbers when something is broken. Everything runs in your browser — your data is never uploaded anywhere.
JSON Formatter & Validator
Paste messy JSON, get clean formatted output, a collapsible tree view, or minified code — free, no signup.
How to Use the JSON Formatter
- Paste your JSON into the dark editor box — or click “Try sample” to see it in action.
- Click Format to beautify (choose 2 spaces, 4 spaces or tab indent), Minify to compress to one line, or Validate to check correctness.
- Switch between the Formatted view (syntax-highlighted code) and the Tree view (collapsible nested structure).
- Use Copy or Download .json to take the result with you.
Find JSON Errors Instantly
The validator doesn’t just say “invalid” — it tells you the exact line and column where parsing failed, with a snippet of the surrounding code. The most common JSON errors are trailing commas ({"a":1,}), single quotes instead of double quotes, unquoted keys, and comments (standard JSON doesn’t allow them). Fix the highlighted spot and re-validate.
Why This Formatter Is Private
Most online formatters send your JSON to their server. This one parses everything with JavaScript on your own device — API keys, configs and payloads never leave your browser. You can disconnect the internet after the page loads and it keeps working.
Frequently Asked Questions
How do I validate JSON online?
Paste your JSON into the tool above and click Validate. If it's valid you'll see a confirmation with key count and depth; if not, the tool shows the exact line and column of the error with a code snippet, so you can fix it in seconds.
What does JSON minify do?
Minify compresses JSON by removing all unnecessary whitespace and line breaks, producing the smallest possible single-line string. Use it before sending data over a network or storing it — smaller payloads load faster. Use Format when humans need to read it.
Is my JSON data safe in this tool?
Yes. Unlike most online formatters, this tool never uploads your data — all parsing happens in your browser on your own device. Paste API responses and config files without worry.
What's the difference between Formatted view and Tree view?
Formatted view shows the full JSON as color-coded code — best for reading and copying. Tree view renders the same data as a collapsible nested structure — best for exploring deep objects and arrays, since you can collapse branches you don't care about.
Why does my JSON show as invalid?
The four most common causes: a trailing comma after the last item, single quotes instead of double quotes around strings, unquoted object keys, and comments (standard JSON forbids them). The validator pinpoints the exact line — fix that spot and validate again.
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