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JSON Formatter

Format, validate & minify JSON

Input JSON
Output

About JSON Formatter

Paste JSON, get readable JSON. That's it. The formatter adds proper indentation so you can actually read what an API returned. The validator catches syntax errors — trailing commas, unquoted keys, single quotes where doubles are required — and tells you the exact line. Minify mode strips whitespace when you need to shave bytes off a payload. Everything runs locally in the browser. The JSON never leaves your tab.

Common Use Cases

  • →Making API responses readable when debugging
  • →Catching syntax errors in JSON config files before deploy
  • →Minifying JSON payloads in production builds
  • →Quickly comparing structure before and after a transformation

Frequently Asked Questions

Does my JSON get sent to a server?+
No. Formatting and validation run entirely in the browser via JavaScript. Nothing is transmitted.
What is the size limit?+
There is no enforced limit. The practical cap is whatever your browser can hold in memory — multi-megabyte files work fine on any modern machine.
Format vs Minify — what is the actual difference?+
Format (pretty-print) adds indentation and newlines so a human can read the structure. Minify removes all of that whitespace to reduce file size. Same data, different presentation.
Why is my JSON invalid?+
Common culprits: trailing comma after the last property, single quotes instead of double quotes, unquoted property keys, or JavaScript-specific values like undefined and NaN that are not valid JSON. The error message shows exactly where to look.