JSON Formatter
Format, beautify, and validate JSON with syntax highlighting.
Paste your JSON to instantly format it with proper indentation and syntax highlighting. Invalid JSON will show error messages with line numbers. Everything runs locally in your browser.
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What is JSON Formatter?
JSON Formatter is a free online tool that formats, beautifies, and validates JSON data. It adds proper indentation, highlights syntax with colors, and identifies errors in invalid JSON with specific line numbers.
When Should You Use This Tool?
Use this tool when you receive minified JSON from APIs, need to debug JSON syntax errors, want to make JSON more readable for documentation, or need to validate JSON before using it.
How to Use JSON Formatter
- 1Paste your JSON into the input area.
- 2The tool automatically formats and validates the JSON.
- 3View the formatted result with syntax highlighting.
- 4If there are errors, check the error message for the line number.
- 5Adjust indentation size if needed (2 or 4 spaces).
- 6Copy the formatted JSON using the Copy button.
How Does This Tool Work?
This tool uses JavaScript's built-in JSON.parse() to validate your JSON and JSON.stringify() with indentation to format it. Syntax highlighting is done with a custom tokenizer. All processing happens in your browser.
Privacy Note: Runs entirely in your browser. Your data never leaves your device. No file uploads to any server.
Common Use Cases
API Developers
Format API responses for debugging and documentation.
Backend Developers
Validate JSON configuration files.
QA Engineers
Make test data readable and validate payloads.
Data Analysts
Format JSON exports for review.