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Free JSON Formatter & Validator
🔒 100% private — runs in your browser, nothing uploaded
Paste minified or messy JSON and get clean, indented output — or minify it for production. Invalid JSON gets a clear, human-readable error message pointing at the exact problem. Built for developers, runs 100% in your browser.
Auto-fix handles: trailing commas, single quotes, unquoted keys, and missing commas between values.
How to Format JSON Online
- Step 1: Paste your minified or messy JSON in the box.
- Step 2: Click Format / Beautify for readable output, or Minify for production.
- Step 3: Invalid JSON? Get a clear error message with the exact position.
Why Use Our JSON Formatter?
- Format, minify, and validate in one place
- Human-readable error messages with character positions
- Private — safe for sensitive API payloads
- Built for developers, runs 100% in-browser
Frequently Asked Questions
What does the validator check?
It parses your input with a strict JSON parser and reports the exact character position and reason for any syntax error.
Is my JSON data sent to a server?
Never. Formatting and validation run entirely in your browser — safe even for sensitive API payloads.
What's the difference between format and minify?
Format adds indentation and line breaks for readability; minify strips all whitespace for the smallest possible size.