JSON Formatter & Validator
Free JSON formatter — paste any JSON to format, validate, and minify it instantly. Highlights errors and shows the cleaned output. Runs entirely in browser.
The JSON Formatter takes raw, minified, or poorly indented JSON and formats it into clean, readable output with proper indentation. It also validates the input and shows a clear error message pointing to the exact line if the JSON is malformed.
You can switch between formatted (pretty print) and minified views. Minified output is useful when you need to paste JSON into a URL parameter or store it compactly. Formatted output is useful when reading or debugging API responses.
Paste JSON from an API response, a config file, or a database field, and the formatter makes it readable in one click. It also handles JSON arrays and deeply nested objects without issue.
Frequently Asked Questions
- Can it detect and show me where the JSON error is?
Yes. If the JSON is invalid, the tool parses it and highlights the line and position of the first error with a description of what went wrong.
- Can I sort the keys alphabetically?
Yes. There is an option to sort object keys alphabetically in the output, which is useful for comparing two JSON objects or normalizing output for version control.
- What is the maximum size of JSON it can handle?
The tool handles JSON up to several megabytes comfortably in most browsers. Extremely large files (tens of megabytes) may be slow to process depending on available memory.
- Is there a free JSON formatter and validator online?
Yes. This JSON formatter is completely free. Paste any JSON string to format it with proper indentation, validate the syntax, and identify errors. No account or server upload required — runs entirely in your browser.
- How do I validate JSON syntax?
Paste your JSON into the formatter. If the JSON is valid, it formats cleanly. If there is a syntax error, the tool highlights the problem area and shows an error message. Common JSON errors include missing commas, trailing commas, unquoted keys, and single quotes instead of double quotes.
← Back to all free tools