JSON Formatter & Validator
Format, beautify, and validate JSON instantly
How to Use
- 1Paste your JSON into the input panel on the left
- 2See the formatted result instantly on the right
- 3Adjust indentation or sort keys using the controls
- 4Copy the result or download as a file
Features
- Real-time formatting as you type
- Syntax error detection with messages
- Adjustable indentation (2 or 4 spaces)
- Minify mode to compress JSON
- Sort keys alphabetically
- Works offline — runs in your browser
What is JSON?
JSON (JavaScript Object Notation) is the most common data format for web APIs and configuration files. While machines read JSON fine, humans need it formatted with proper indentation and line breaks to understand the structure.
This free JSON formatter takes any valid JSON — whether minified, poorly indented, or copied from a console log — and restructures it into a clean, readable format. It also validates the syntax and shows exactly where errors occur.
Everything runs in your browser. Your data never leaves your device, making this safe for sensitive information like API keys or authentication tokens.
FAQ
Is my JSON data safe?
Yes. This tool runs entirely in your browser using JavaScript. Your data is never sent to any server. You can verify this by using the tool offline — it works without an internet connection.
What is the maximum JSON size I can format?
There is no fixed limit. Since processing happens in your browser, the limit depends on your device memory. Most modern devices handle JSON files up to 50-100 MB without issues.
Why is my JSON showing an error?
Common JSON errors include: missing commas between items, trailing commas after the last item (not allowed in JSON), using single quotes instead of double quotes, and unquoted property names.
What is the difference between JSON and JavaScript objects?
JSON is a text format that looks like JavaScript objects but has stricter rules: all property names must be double-quoted, only double quotes are allowed for strings, no trailing commas, no comments, and no undefined values.