JSON Formatter — Free Online JSON Beautifier, Minifier & Validator
Format, minify, and validate JSON data instantly in your browser. Analyze key count, depth, and size — all processed locally with no server upload.
Output will appear hereFrequently Asked Questions
Q. Is my JSON data sent to a server?
No. All processing happens in your browser. You can safely use sensitive data.
Q. Can I validate invalid JSON?
Yes — entering invalid JSON immediately shows the error location and reason.
Q. Can I change the indentation size?
Yes — choose 2, 4, or 8 spaces. The default is 2 spaces.
Q. When should I use Minify?
Use it to reduce payload size for API requests or to save bandwidth in production environments.
Q. Can it handle large JSON files?
Yes, within browser memory limits. Files of several MB are typically processed without issues.
Q. What is the difference between JSON and a JavaScript object?
JSON keys must be double-quoted and trailing commas are not allowed. JavaScript objects have no such restrictions.
How to Use
Paste your JSON data into the left input area.
Click Format, Minify, or Validate.
The processed JSON and stats (key count, depth, size) appear on the right.
Click the copy button to save the result to your clipboard.
Expert Knowledge: JSON Formatter — Free Online JSON Beautifier, Minifier & Validator
JSON (JavaScript Object Notation) is a lightweight data exchange format designed by Douglas Crockford in 2001. Defined by ECMA-404 and RFC 8259, it is the de facto standard for REST APIs. Common JSON parse errors: ① missing double-quotes around keys, ② trailing commas after the last element, ③ using single quotes instead of double quotes. JSON Schema allows you to define and validate JSON structure ahead of time, improving API reliability.
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