JSON Formatter & Validator
Beautify, minify and validate JSON. Get clear error messages with line numbers and a collapsible tree view.
Programmer case converter
| camelCase | helloWorldExample |
| PascalCase | HelloWorldExample |
| snake_case | hello_world_example |
| kebab-case | hello-world-example |
| CONSTANT_CASE | HELLO_WORLD_EXAMPLE |
How to use the JSON Formatter & Validator
- Paste your JSON into the input area.
- Choose an indent size (2 spaces, 4 spaces or tab) or click Minify.
- If the JSON is invalid, read the error message and line number.
- Copy the formatted output or download it as a .json file.
Examples
| Input | Output | Notes |
|---|---|---|
{"name":"Ada","skills":["math","code"]} | {
"name": "Ada",
"skills": [
"math",
"code"
]
} | Beautify with 2-space indent |
{
"a": 1,
"b": 2
} | {"a":1,"b":2} | Minify |
{"a": 1,} | Error: Unexpected token } at line 1 | Validation catches the trailing comma |
What is JSON?
JSON (JavaScript Object Notation) is a lightweight, text-based data format built from objects (key/value pairs), arrays, strings, numbers, booleans and null. It is the default format for web APIs and config files because it is easy for both people and machines to read.
Beautify vs minify
Use beautify while developing and debugging so structure is visible. Use minify for production payloads and storage to cut bytes — a minified response can be 20–50% smaller.
Reading validation errors
The validator reports the position of the first syntax error. Fix that one, re-run, and repeat — one broken bracket often masks the real problem further down.
Frequently asked questions
What does a JSON formatter do?
It re-indents JSON so nested objects and arrays are readable ("beautify"), or strips all whitespace to make it as small as possible ("minify"). It also checks that the JSON is syntactically valid.
Why is my JSON invalid?
The most common causes are trailing commas, single quotes instead of double quotes, unquoted keys, and missing commas or brackets. The error message points to the line where parsing failed.
Is my JSON sent to a server?
No. Parsing and formatting happen in your browser with the native JSON engine, so sensitive payloads never leave your machine.
What is the difference between JSON and JSON5?
JSON5 is a relaxed superset that allows comments, trailing commas and unquoted keys. This tool can optionally parse JSON5-style input but always outputs strict JSON.
Can it sort object keys?
Yes. Enable "sort keys" to alphabetically order the keys of every object, which is useful for diffing two config files.