Format, validate and minify JSON with clear error reporting.
Parsed locally — your data is never uploaded.
How do you format and validate JSON?
A JSON formatter parses your input with the browser's native JSON engine, then re-serialises valid JSON with your chosen indentation to beautify it, or with no whitespace to minify it. Formatting only changes whitespace, never your data. If the JSON is invalid, the tool shows the parser's error message and position instead of producing output, so you can fix it quickly.
Understanding your result
Formatting only changes whitespace, never your data. If the JSON is invalid, the tool shows the parser’s error message and position instead of producing output.
Formula and method
The tool parses your input with the browser’s native JSON engine. Valid JSON is re-serialised with your chosen indentation for formatting, or with no whitespace for minifying.
Assumptions and limitations
The tool checks that your JSON is syntactically well formed against the standard; it does not validate against a schema, so it cannot tell you whether a field is missing or has the wrong type. It touches whitespace only and never reorders keys or alters values.
Worked example
The input {"a":1,"b":[2,3]} formatted with 2 spaces becomes a clean, indented, multi-line structure that is easy to read and review.
How to use this tool
- Paste your JSON into the input box.
- Choose your preferred indentation.
- Press Format to beautify, or use Minify and Validate.
Common mistakes to avoid
- Using single quotes — JSON requires double quotes around keys and strings.
- Leaving a trailing comma after the last item.
- Pasting JavaScript objects with unquoted keys.
About the JSON Formatter
The JSON Formatter cleans up messy JSON, validates that it is well formed and can compress it to a single line. It reports the exact location of syntax errors so you can fix them fast.
Who should use this tool
Back-end and front-end developers debugging API responses, engineers reviewing config files, and QA testers inspecting payloads. Anyone who pastes a wall of unindented JSON from a log or network tab and needs it readable, validated, or squeezed onto one line before committing.
Benefits
- Pinpoints the exact position of a syntax error for quick fixes
- Re-indents dense JSON into a readable, reviewable structure
- Minifies to a single line to trim payload size
- Runs entirely in your browser, so pasted data stays private
Practical use cases
- Tidying an API response copied from browser dev tools
- Validating a config file before deploying it
- Minifying JSON to shrink a request body
- Reviewing a colleague's payload in a readable layout
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Frequently asked questions
Is my data sent to a server?
No. Parsing and formatting happen entirely in your browser.
What is minifying?
Minifying removes all unnecessary whitespace to produce the smallest valid JSON, useful for transmission.
Does the JSON formatter reorder or sort my keys?
No. Formatting only adds or removes whitespace such as indentation and line breaks. Your keys stay in their original order, and every value is preserved exactly. If you need alphabetical keys, that is a separate transformation this tool deliberately avoids.
Can it validate JSON against a schema?
No. It confirms that your input is syntactically valid JSON, catching mistakes like trailing commas or unquoted keys. It does not check field names, types, or required properties against a JSON Schema, so structurally valid but semantically wrong data will still pass.