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Open →Free JSON Formatter & Validator
Paste messy JSON, get clean indented JSON back — or minify it. Invalid JSON gets a plain-English error message.
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100% free · No signup · Your data never leaves your browser.
What is a JSON formatter?
A JSON formatter is a free online tool that validates JSON and rewrites it neatly indented (pretty-print) or compressed onto one line (minify). Developers use it to read API responses, find syntax errors and prepare JSON for production.
Pretty-print vs minify
- Pretty-print adds indentation and line breaks so humans can read nested JSON easily — ideal for debugging API responses.
- Minify strips all unnecessary whitespace, producing the smallest valid JSON — ideal for pasting into code or requests where size matters.
How error messages help
When JSON is invalid, the tool tells you exactly what went wrong and where — for example an unexpected character at a specific position. Common culprits are trailing commas, single quotes instead of double quotes, and unescaped line breaks inside strings.
Private by design
Validation and formatting run entirely in your browser. API keys, tokens and payloads you paste are never uploaded or stored anywhere.
Frequently asked questions
Is this JSON formatter free?
Yes — free forever, no signup, no limits.
Is my JSON data uploaded to a server?
No. Parsing happens locally in your browser, so sensitive payloads stay on your device.
What does minify do?
It removes all optional whitespace — newlines, spaces and indentation — leaving valid JSON on a single line, as small as possible.
Why does it say my JSON is invalid?
The usual causes: a trailing comma after the last item, single quotes instead of double quotes, comments, or special characters that aren't escaped.
Can it handle large JSON files?
Yes — pasting tens of thousands of lines works fine since everything runs locally.
Does it work offline?
Yes. Once the page has loaded, no internet connection is needed.
Short answer: A JSON formatter is a free online tool that validates JSON and rewrites it neatly indented (pretty-print) or compressed onto one line (minify). Developers use it to read API responses, find syntax errors and prepare JSON for production.
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