JSON Formatter
Free JSON formatter online — no signup required. Beautify, validate, and minify JSON instantly in your browser with syntax highlighting and precise error reporting. 100% client-side.
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Features
- Pretty-print JSON with proper indentation
- JSON validation with exact error line numbers
- Minify JSON to a single line for production use
- Syntax highlighting for keys, strings, numbers, and booleans
- Instant formatting — no submit button needed
- Copy formatted or minified output in one click
Frequently Asked Questions
What is a JSON formatter and beautifier?
A JSON formatter (also called a JSON beautifier) takes compact or unindented JSON text and re-formats it with consistent indentation and line breaks, making it easy to read and debug.
How do I format and validate JSON online?
Paste your JSON payload and click Format to pretty-print it. If the syntax is invalid, the tool shows the exact line number and error message so you can fix commas, brackets, or quotes quickly.
What is the difference between JSON pretty print and minify?
Pretty-print adds indentation and line breaks for human readability during development and debugging. Minify strips all whitespace to produce a compact single-line payload for smaller transfers in production.
Why does my JSON fail validation?
Common causes: trailing commas, single-quoted strings, unquoted keys, comments (not allowed in strict JSON), or JavaScript-only values like undefined. Fix the reported line and run validation again.
Can I validate JSON online for free?
Yes. This free JSON validator works entirely in your browser — no signup, no file uploads, no rate limits. Paste your JSON and get instant validation results.