JSON Formatter & Validator
Pretty-print, minify and validate JSON instantly in your browser. Get the exact line and column of any syntax error — and your data never leaves your device.
How to use it
- 1Paste your JSON
Type or paste JSON into the editor, or load a .json file. Everything stays in your browser.
- 2Format or minify
Click Format to pretty-print with your chosen indentation, or Minify to strip whitespace for the smallest possible output.
- 3Fix any errors
If the JSON is invalid, you get the exact line, column and reason, so you can jump straight to the problem.
- 4Copy or download
Copy the result to your clipboard or download it as a file.
Format, minify and validate
Paste messy JSON and get clean, indented output you can actually read — or minify it down to the smallest valid form for production. Invalid JSON is caught immediately with the exact line and column of the problem.
Fast and completely private
Your JSON often contains sensitive data. Here it’s parsed entirely in your browser and never sent anywhere, so you can format configuration, API responses and secrets with confidence.
Frequently asked questions
Is my JSON sent to a server?
No. Parsing, formatting and validation all happen locally in your browser. Your data never leaves your device.
How precise is the error reporting?
Invalid JSON is reported with the exact line and column plus a human-readable message, so you can fix it quickly.
Can it handle large JSON files?
Yes. Formatting is designed to handle large inputs without freezing the page.
What’s the difference between format and minify?
Format (pretty-print) adds indentation and line breaks for readability; minify removes all unnecessary whitespace to produce the smallest valid JSON.
Does it support comments (JSONC)?
Standard JSON does not allow comments. The validator follows the JSON specification, so you can be confident the output is valid everywhere.