Formatted JSON will appear here...
How to Use This Tool
Step 1
Paste your JSON
Paste raw JSON into the left panel. Use the Paste button or Ctrl+V. Click Sample to load example data with nested structures.
Step 2
View formatted output
The right panel instantly shows your JSON with syntax highlighting. Errors appear with descriptions to help you fix invalid JSON.
Step 3
Adjust & explore
Switch between 2-space, 4-space, or tab indentation. Click Minify to compress. Click Tree to explore as a collapsible tree view.
Step 4
Copy & use
Click Copy to grab the formatted or minified output. The stats bar shows key count, nesting depth, and size at a glance.
Frequently Asked Questions
What is JSON formatting?
JSON formatting (also called pretty-printing or beautifying) adds indentation and line breaks to make compact JSON data human-readable. Minified JSON saves bandwidth for APIs and storage, but formatted JSON is far easier to read, debug, and review in code. This tool lets you switch between both formats instantly.
Is my JSON data sent to a server?
No. All JSON parsing, formatting, validation, and tree rendering happens entirely in your browser using JavaScript. Your data never leaves your device — nothing is transmitted, stored, or logged. You can verify this by checking the Network tab in your browser's developer tools.
What causes JSON validation errors?
The most common JSON errors are: trailing commas after the last item in an array or object (e.g.,
[1, 2, 3,]), single quotes instead of double quotes ('hello' vs "hello"), unquoted property names, comments (JSON does not support // or /* */ comments), missing or extra brackets/braces, and using undefined, NaN, or Infinity which are not valid JSON values.
What is the difference between JSON and a JavaScript object?
JSON is a strict data interchange format that is a subset of JavaScript object syntax. JSON requires all keys and string values to be wrapped in double quotes, does not allow trailing commas, and cannot contain functions,
undefined, comments, or special numeric values like NaN. JavaScript objects are more permissive — they support unquoted keys, single quotes, trailing commas, methods, and all JavaScript value types.
What is the maximum size of JSON this tool can handle?
Since all processing happens in your browser, the limit depends on your device's available memory. Most modern browsers can comfortably handle JSON files up to 5-10 MB. For very large files (50 MB+), you may notice slower formatting. The tree view is best suited for files under 1 MB, as rendering many DOM nodes can impact performance.