JSON Formatter & Validator
Beautify · Minify · Validate · Syntax highlighting · Key/object/array stats · Free · Runs in browser
JSON Syntax Quick Reference
| Type | Syntax | Example |
|---|---|---|
| String | "key": "value" | "name": "ClickyFix" |
| Number | "key": 123 | "count": 42 |
| Boolean | "key": true / false | "active": true |
| Null | "key": null | "middleName": null |
| Array | "key": [item1, item2] | "tags": ["free", "tool"] |
| Object | "key": { "nested": "value" } | "meta": {"v": 1} |
Common JSON Errors
✗ Trailing comma
{"name": "Alice",}Remove the comma after the last item in objects and arrays — JSON does not allow trailing commas.
✗ Single quotes
{'name': 'Alice'}JSON requires double quotes for strings and keys. Single quotes are not valid JSON.
✗ Unquoted keys
{name: "Alice"}Object keys must be quoted strings in JSON. Use double quotes around all keys.
✗ Comments
{"name": "Alice" // comment}JSON does not support comments. Remove all // and /* */ comments before parsing.
✗ Undefined / NaN / Infinity
{"value": undefined}JSON only supports null, not undefined, NaN, or Infinity. Replace these with null or remove the key.
Frequently Asked Questions
Is my JSON sent to a server?
No. Formatting and validation runs entirely in your browser using JavaScript's built-in JSON.parse() and JSON.stringify(). Your data never leaves your device.
What is the difference between Format and Minify?
Format (beautify) adds indentation and line breaks to make JSON human-readable. Minify removes all whitespace to produce the smallest possible string, which is what you'd send over an API. Both represent exactly the same data structure.
Why is 2 spaces better than 4 spaces for JSON?
2 spaces is more compact — deeply nested JSON stays readable within a typical editor or terminal width. Many style guides (including Google's and Airbnb's) use 2 spaces. 4 spaces is common in Windows-oriented tooling. The choice is purely aesthetic.
Can I use this to format JSON from an API response?
Yes — copy the raw JSON from your browser's network tab, Postman, curl output, or any other source, paste it here, and click Format. The key/object/array stats are also useful for quickly understanding an unfamiliar API response structure.