JSON Formatter
Paste messy or minified JSON and get clean, readable, validated output in one click. This free online JSON formatter pretty-prints, minifies, and validates JSON, pointing you straight to syntax errors.
About the JSON Formatter
JSON (JavaScript Object Notation) is the most common format for APIs and config files, but raw responses are often minified into a single unreadable line. A formatter re-indents that data into a clear hierarchy so you can scan keys, nesting, and values at a glance.
Validation catches the small mistakes that break parsers — trailing commas, unquoted keys, mismatched brackets — before they reach production. Because everything here runs locally in your browser, you can safely format JSON that contains internal or sensitive data without it ever leaving your machine.
How to use it
- 1Paste your JSON into the input panel on the left.
- 2Choose Beautify to pretty-print or Minify to compact it.
- 3Fix any errors highlighted in the status bar, then Copy the result.
Features
- Pretty-print with configurable indentation, or minify to a single line
- Instant validation with the exact line/position of any syntax error
- Collapsible tree view to explore deeply nested JSON
- One-click copy and download of the result
Frequently asked questions
Is this JSON formatter free?
Yes. Every tool on Appachi Tools is completely free, with no signup, no ads injected into your data, and no usage limits.
Is my JSON uploaded to a server?
No. All formatting and validation happens entirely in your browser using JavaScript. Your JSON never leaves your device, so it is safe to use with private data.
What does “validate JSON” mean?
Validation checks that your text conforms to the JSON specification (RFC 8259). If something is malformed — a missing quote, trailing comma, or bad bracket — the tool reports where the error is.
Can I minify JSON too?
Yes. Use the Minify option to strip all whitespace and produce the smallest valid JSON, which is useful for reducing payload size.