JSON Formatter & Validator — Format & Fix JSON Free Online
DeveloperPaste minified or broken JSON and fix it instantly. Validates syntax, pinpoints errors by exact position, and minifies for production. Free online JSON formatter.
About the JSON Formatter & Validator — Format & Fix JSON Free Online
Our free JSON formatter, validator and minifier helps developers work with JSON data faster and more accurately. Paste raw, minified or malformed JSON and instantly get a perfectly indented, human-readable output with syntax highlighting. The validator pinpoints exact errors — missing commas, unclosed brackets, incorrect data types — so you can fix them without manually scanning hundreds of lines. The minifier strips all whitespace for production-ready compact JSON. Used daily by front-end developers, backend engineers, data analysts and QA testers who work with APIs, configuration files, databases and data pipelines. All processing runs in your browser — your JSON data is never sent to any server.
How to Use the JSON Formatter & Validator — Format & Fix JSON Free Online
- 1
Paste your raw, minified or malformed JSON into the input box on the left.
- 2
Click Format JSON to beautify it with proper indentation and line breaks.
- 3
If the JSON contains errors, a red error message shows the exact line and type of the problem.
- 4
Fix the error in the input box and click Format JSON again.
- 5
Click Minify to compress the formatted JSON into a single compact line for production use.
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Click Copy to copy the output to your clipboard.
Frequently Asked Questions
What is JSON and why does formatting matter?
JSON (JavaScript Object Notation) is the most widely used data format for APIs, configuration files and data storage. Minified JSON from APIs is a single unbroken line that is impossible to read manually. Formatting adds indentation and line breaks so you can understand the structure, debug issues and edit values correctly.
How does the JSON validator detect errors?
The validator parses your JSON using the JavaScript JSON.parse() engine and reports the exact location and type of any syntax error — for example, 'Unexpected token at position 142' or 'Missing comma after property'. This is far faster than scanning raw JSON manually.
What are the most common JSON errors?
The five most common JSON errors are: trailing commas after the last item in an array or object (not allowed in JSON), single quotes instead of double quotes for strings, unquoted property names, missing commas between items, and mismatched brackets or braces.
What is the difference between JSON and JavaScript objects?
JSON looks similar to JavaScript objects but has stricter rules: all property names must be in double quotes, values can only be strings, numbers, booleans, null, arrays or other objects (no functions or undefined), and trailing commas are not allowed. Our formatter validates against these strict JSON rules.
Is my JSON data sent to a server?
No. All formatting, validation and minification runs entirely in your browser using the native JSON.parse() and JSON.stringify() functions. Your data never leaves your device.
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