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Format, validate, beautify, and minify your JSON data instantly — right in your browser. No data is sent to any server. Everything runs locally with JavaScript for maximum privacy and speed. Used by thousands of developers daily for debugging APIs, formatting configuration files, and validating JSON data structures.
Ctrl+Enter) to beautify and validate instantlyCtrl+Enter to format, Tab to indentA JSON formatter (also called JSON beautifier or JSON pretty printer) takes raw or minified JSON and reformats it with proper indentation and line breaks for readability. A JSON validator checks whether JSON conforms to the JSON specification (RFC 8259) and reports syntax errors.
This tool does both simultaneously — when you click Format, it parses your JSON (validating it), then outputs it with clean formatting. If there are errors, you get detailed error messages with exact line and column numbers, plus visual highlighting of the problematic area.
These are the most frequent JSON syntax errors developers encounter:
{"a": 1, "b": 2,} — Remove the comma after the last item, or use our Repair feature{'key': 'value'} — JSON requires double quotes. Use Repair to auto-convert{key: "value"} — All keys must be in double quotes{"key": "value" // comment} — JSON does not support comments. Use Repair to strip them{"a": 1 "b": 2} — Add commas between key-value pairsnull insteadJSON (JavaScript Object Notation) is a lightweight, text-based data interchange format. Despite its name, JSON is language-independent and is used across virtually all programming languages including Python, Java, C#, Go, Ruby, PHP, and JavaScript.
"hello world"42, 3.14, -1e10true or falsenull{"key": "value"}[1, 2, 3]JSON is the de facto standard for:
package.json, tsconfig.json, .eslintrc.jsonA JSON formatter is an online tool that takes raw or minified JSON data and reformats it with proper indentation and line breaks, making it easy to read and debug. It typically also validates the JSON syntax and highlights errors. This tool formats, validates, minifies, repairs, and visualizes JSON — all in one place.
Yes. This JSON formatter runs entirely in your browser. No data is transmitted to any server. You can verify this by opening your browser's Network tab in Developer Tools — you'll see zero outbound requests when formatting. You can even disconnect from the internet and the tool will still work perfectly.
This tool handles JSON up to 5MB comfortably in most modern browsers. Performance depends on your device's memory and processing power. For extremely large JSON files (50MB+), consider using a desktop editor like VS Code with a JSON extension.
First, click Format to see the exact error with line and column numbers. Common fixes include: adding missing commas, replacing single quotes with double quotes, quoting keys, and removing trailing commas or comments. You can also click Repair to automatically fix many common issues.
Absolutely. Paste your JSON and click Format. If it's valid, you'll see a green "✓ Valid JSON" status with statistics. If not, you'll get a detailed error message with the line and column where the problem was found, plus visual highlighting of the error location.
A JSON formatter reformats JSON with proper indentation for readability. A JSON validator checks whether JSON is syntactically correct. This tool does both simultaneously — formatting and validating in one click.
Yes! Click the URL button in the toolbar, enter any API endpoint URL, and the tool will fetch the JSON and format it automatically. This is perfect for debugging API responses.
The Repair feature can handle some JSON5/JSONC syntax like trailing commas, single quotes, and comments — automatically converting them to valid JSON. For full JSON5 support, the Repair function strips comments and fixes common deviations from strict JSON.
Ctrl+Enter (or Cmd+Enter on Mac) formats the JSON. Tab inserts indentation in the input editor. The tool also auto-formats when you paste JSON.