Free Online JSON Formatter and Validator
HubKit's JSON Formatter lets you pretty-print, minify, and validate JSON data instantly in your browser. Whether you're debugging API responses, cleaning up configuration files, or preparing JSON payloads, this tool formats your data with proper indentation and highlights syntax errors in real time. No data is sent to any server — everything runs locally.
How to Use
Paste your JSON into the input pane or click Sample to load example data. Choose Pretty to add indentation (2 or 4 spaces, or tabs) or Minify to strip all whitespace. The output updates instantly as you type. Copy the result to your clipboard or download it as a .json file.
Features
- Pretty-print JSON with 2-space, 4-space, or tab indentation
- Minify JSON to a single compact line
- Real-time JSON validation with error messages
- Works offline — no server processing required
Frequently Asked Questions
Is my JSON data safe when using this formatter?
Yes. All processing happens directly in your browser using JavaScript. Your JSON data is never uploaded to any server, making it safe for sensitive or proprietary data.
What is the maximum JSON size this tool can handle?
The tool can handle JSON files up to several megabytes. Performance depends on your browser and device, but typical API responses and config files work instantly.
Can I use this tool to validate JSON?
Yes. The formatter automatically validates your input and shows a green "Valid JSON" badge or displays the specific error message if the JSON is malformed.
What is the difference between pretty-print and minify?
Pretty-print adds indentation and line breaks to make JSON human-readable. Minify removes all unnecessary whitespace, producing the smallest possible output — ideal for API payloads and storage.