Free tool
JSON Formatter & Validator
Pretty-print, minify and validate JSON — entirely in your browser.
About this tool
Format, validate and minify JSON in your browser. Paste in raw JSON and we'll pretty-print it with your chosen indentation, or compress it down for production. Invalid JSON shows a clear error with the line and column so you can fix it fast.
How to use the Free JSON Formatter & Validator
- Paste your JSON into the input panel.
- Choose your indentation (2 spaces, 4 spaces or tabs).
- Click Format to pretty-print, or Minify to compress.
- If your JSON is invalid, read the error message — it points to the exact line.
- Copy the formatted result to the clipboard with one click.
Frequently asked questions
- Is my JSON uploaded anywhere?
- No. Parsing and formatting use JSON.parse and JSON.stringify directly in your browser.
- Why does my JSON fail to parse?
- Common causes: trailing commas, single quotes instead of double quotes, or unquoted keys. The error message shows the line and column of the problem.
- Can it handle large JSON files?
- Yes — within the limits of your browser's memory. Files of several MB are usually fine.
- Does it support JSON5 or comments?
- No — we use strict JSON. Remove comments and trailing commas before formatting.