JSON Formatter & Validator
Format, validate, beautify, and minify JSON strings locally in your browser with precise syntax error messages and instant download controls.
How the JSON Formatter works
The JSON Formatter parses your input string using strict JSON.parse() specifications. When valid, it formats the data structure into clean, human-readable JSON using JSON.stringify() with your selected indentation depth (2 spaces, 4 spaces, or tab).
Best practices for working with JSON
- Double Quotes Only: JSON keys and string values must use double quotes (
"key": "value"). Single quotes ('key') are invalid JSON syntax. - No Trailing Commas: Ensure object properties and array elements do not end with trailing commas (
[1, 2, 3,]is invalid). - Escape Characters: Backslashes, quotes, and control characters must be properly escaped inside JSON strings.
Frequently Asked Questions
Is my confidential JSON payload uploaded to any server or logged?+
Never. All JSON parsing, formatting, validation, and minification runs 100% locally using standard JavaScript in your browser tab memory.
What happens if my JSON has syntax errors?+
The validator highlights the syntax failure immediately with an inline error message indicating the unexpected character or missing bracket/comma.
Can I convert formatted JSON into a compact single-line string?+
Yes. Click the Minify button in the top toolbar to strip all unnecessary whitespaces and linebreaks for production APIs or environment variables.
What indentation options are available?+
You can customize indentation to 2 spaces (standard web API convention), 4 spaces, or 1 tab character.