Working with JSON data is a daily task for developers, QA engineers, and anyone interacting with APIs. Our free online JSON formatter lets you paste raw or minified JSON and instantly pretty-print it with proper indentation, making it readable at a glance. The built-in JSON validator catches syntax errors immediately and tells you exactly what went wrong. Need to send compact JSON in an API request? The Minify button strips all whitespace in one click. Everything runs in your browser — your JSON data never leaves your device, making it safe to use with proprietary API responses or confidential configuration files.
How to Format or Validate JSON
- Paste your JSON into the input area.
- Click Format / Pretty-Print to add proper indentation and line breaks.
- Click Minify to strip all whitespace for compact transmission.
- Click Validate Only to check if the JSON is syntactically valid without reformatting.
- If there is an error, the red status badge shows the exact error message and position.
- Click Copy Output to copy the result to your clipboard.
Common JSON Errors & Fixes
- Unexpected token — usually a trailing comma after the last item in an array or object. Remove it.
- Unterminated string — a string value is missing its closing quote.
- Unexpected end of JSON — a closing
}or]is missing. - Invalid escape character — a backslash in a string needs to be escaped as
.
Frequently Asked Questions
What is the difference between JSON and JavaScript objects?
JSON is a text format derived from JavaScript object syntax, but it is stricter: all keys must be double-quoted strings, trailing commas are not allowed, and functions are not valid values. Use JSON.parse() to convert JSON text to a JavaScript object.
Is my JSON data safe when using this tool?
Yes. The formatter runs entirely in your browser using JavaScript. No data is transmitted to our servers.