JSON Formatter and Validator - Free and Easy Online Tool
JSON Formatter & Validator
Format, validate, beautify, and minify JSON instantly in your browser. Check JSON syntax without uploading your data.
Paste your JSON below. The tool checks its syntax and immediately shows whether it is valid. If valid, you can format or minify the JSON and copy the result.
JSON Formatter & Validator
Validate JSON, format it for readability, or minify it for compact output.
Instant Validation
Check JSON syntax in your browser and see immediately whether the input can be parsed successfully.
Browser-Based Processing
JSON parsing, formatting, and minification happen locally in your browser without requiring an external processing API.
Format or Minify
Beautify JSON for debugging and readability or remove unnecessary whitespace for compact output.
Free JSON Formatter and Validator
A JSON formatter makes structured data easier to read by adding indentation and line breaks. A JSON validator checks whether the supplied text follows valid JSON syntax and can be parsed correctly.
This free JSON formatter combines both functions with JSON minification. You can paste an API response, configuration object, webhook payload, or other JSON data and process it directly in your browser.
What Is JSON?
JSON, or JavaScript Object Notation, is a text-based format commonly used to represent structured data. It is widely used for APIs, application configuration, web applications, integrations, and data exchange between software systems.
JSON uses objects, arrays, strings, numbers, booleans, and the
null value to represent data.
What Does a JSON Validator Check?
This tool uses the browser's native JSON parser to determine whether the input can be parsed as JSON. If parsing succeeds, the JSON is considered valid for the parser. If parsing fails, the tool displays the parser's error message.
Common JSON Syntax Errors
| Problem | Invalid Example | Valid JSON |
|---|---|---|
| Unquoted key | {name: "John"} |
{"name": "John"} |
| Single quotes | {'name': 'John'} |
{"name": "John"} |
| Trailing comma | {"name":"John",} |
{"name":"John"} |
| Incorrect bracket | {"items":[1,2,3} |
{"items":[1,2,3]} |
| Invalid value | {"active":undefined} |
{"active":null} |
JSON Formatting Rules
JSON has stricter syntax rules than a JavaScript object literal. Some syntax that JavaScript accepts is not valid JSON.
- Object property names must use double quotes.
- JSON string values must use double quotes.
- Objects use curly braces.
- Arrays use square brackets.
- Items are separated with commas.
-
JSON supports
true,false, andnull. -
Values such as
undefined, functions, andNaNare not valid JSON values. - Trailing commas are not valid JSON.
JSON Formatter vs JSON Validator
Formatting and validation are related but different operations. Validation checks whether the input can be parsed as JSON, while formatting changes the presentation of valid JSON by adding indentation and line breaks.
| Function | What It Does | When to Use It |
|---|---|---|
| Validate | Checks whether JSON can be parsed | Finding syntax errors |
| Format | Adds indentation and line breaks | Reading and debugging JSON |
| Minify | Removes unnecessary whitespace | Compact JSON output |
When Should You Use a JSON Formatter?
A JSON formatter is useful whenever structured data is difficult to inspect in its compact form. Developers commonly use formatters while working with APIs, webhooks, configuration files, logs, and application data.
- API debugging: Inspect nested API responses more easily.
- Webhook testing: Review structured webhook payloads.
- Configuration: Check JSON configuration files before using them.
- Development: Format JSON copied from logs or browser developer tools.
- Compact output: Minify valid JSON when whitespace is unnecessary.
How to Format JSON
Paste your JSON into the input field and select Format / Beautify. The tool validates the input before generating formatted output.
If the JSON is invalid, the output remains empty and the status area displays the parser error. Correct the syntax and run the formatter again.
How to Minify JSON
Paste valid JSON into the input field and select Minify. The tool parses the JSON and generates a compact version without unnecessary formatting whitespace.
Frequently Asked Questions
How This JSON Tool Works
Validation uses the browser's native
JSON.parse() function. Formatted output is generated
with JSON.stringify() using two-space indentation.
Minified output uses JSON.stringify() without indentation.
Because the processing is performed client-side, the tool does not need an external JSON-processing API.
Your JSON is processed locally in your browser. Avoid pasting passwords, API keys, access tokens, credentials, or confidential production data into any online utility unless your organization's security policy permits it.
The JSON validation, formatting, minification functionality and tool instructions were reviewed on this date.