JSON Formatter & Validator

Paste your JSON below to format, validate, or minify it instantly.

What Does This JSON Formatter Do?
This tool takes raw or minified JSON data and makes it easy to read. It can format (prettify with indentation), minify (remove whitespace), and validate (check for syntax errors) any JSON input. No data is sent to any server — everything happens locally in your browser.
How to Use
  1. Paste your JSON into the input area
  2. Click Format to prettify with 2-space indentation
  3. Click Minify to compress into a single line
  4. Click Validate to check for JSON syntax errors
  5. Click Copy to copy the output to your clipboard
Common JSON Errors
The most common JSON validation errors include: trailing commas, single quotes instead of double quotes, unquoted keys, and missing brackets. This tool shows you the exact error position so you can fix it quickly.
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What Is the JSON Formatter?
Our JSON Formatter and Validator is a free developer tool that instantly prettifies, minifies, and validates JSON data directly in your browser. Whether you're debugging API responses, cleaning up configuration files, or verifying data structures, this tool makes raw JSON readable and catches syntax errors before they cause runtime failures. Nothing is sent to any server — all processing happens locally on your device for complete privacy.
How to Use This Tool
  1. Paste your JSON — Copy JSON data from your API response, config file, or any source and paste it into the input text area. The tool accepts any valid (or invalid) JSON string.
  2. Choose an action — Click "Format" to prettify with 2-space indentation for readability, "Minify" to compress into a single line for production use, or "Validate" to check for syntax errors without modifying the input.
  3. Copy the result — The output area displays syntax-highlighted JSON. Click "Copy" to grab the formatted or minified result and paste it wherever you need it.
Why Use Our JSON Formatter?
This tool provides instant syntax highlighting with color-coded keys, strings, numbers, booleans, and nulls for easy visual scanning. Error messages pinpoint the exact location of JSON syntax problems so you can fix them quickly. It handles large JSON payloads efficiently, works offline after initial page load, and requires zero setup — no extensions, no IDE plugins, no API keys. It's the fastest path from messy JSON to clean, readable output.
Tips & FAQ
What are the most common JSON errors?
The top mistakes are: trailing commas after the last item in arrays or objects, using single quotes instead of double quotes, unquoted property keys, and missing closing brackets or braces. This tool's error messages identify the exact character position of each issue.
Can I format JSON with comments?
Standard JSON does not support comments (// or /* */). If your data contains comments, you'll need to remove them first. Consider using JSON5 or JSONC for commented configuration files, then strip comments before validating here.
Is there a size limit for the input?
The tool runs in your browser, so it's limited only by your device's available memory. It comfortably handles files up to several megabytes. For extremely large datasets (50MB+), consider using a command-line tool like jq instead.