What is the JSON Formatter & Validator?

The JSON Formatter & Validator takes raw, minified, or malformed JSON and does two things: formats it into a readable, indented structure, and validates it for syntax errors. Both happen instantly as you type or paste.

It's one of the most-used tools in everyday web development — JSON is everywhere (APIs, config files, databases, logs), and it's frequently encountered in a compressed or broken state that's nearly impossible to read or debug without formatting it first.

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How to Use the Formatter

1. Paste your JSON into the input editor. This can be minified single-line JSON, a copied API response, a log entry, or anything else.
2. Click Format to apply indentation and line breaks, making the structure visible and readable.
3. Check for errors. If the JSON has a syntax error, the validator highlights the problem and shows the line and character position where parsing failed.
4. Copy the output using the copy button. You can also minify the formatted JSON back to a compact form using the Minify option.

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Formatting vs Validation

Formatting (also called beautifying or pretty-printing) adds consistent indentation and line breaks to make the structure readable. It doesn't change any data — only the whitespace.

Validation checks whether the JSON is syntactically valid according to the JSON specification. Common errors it catches:

• Trailing commas after the last item in an object or array — valid in JavaScript but not in JSON
• Single-quoted strings — JSON requires double quotes for all strings and keys
• Missing commas between key-value pairs
• Unmatched or missing brackets and braces
• Unquoted keys — all JSON keys must be strings in double quotes
• Invalid values — undefined, functions, and comments are not valid JSON

When an error is detected, the tool pinpoints the exact location so you can fix it without scanning the entire document.

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Minification

The Minify option removes all whitespace from the JSON, producing the most compact possible representation. Minified JSON is appropriate for:

• API responses where bandwidth matters
• Storing JSON in a database field
• Embedding JSON in source code as a string literal
• Any context where the JSON will be machine-read rather than human-read

Always keep a formatted version for development and version control — only minify the output that goes to production.

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Common Use Cases

Debugging API responses — paste a raw API response to instantly see its structure, find the field you're looking for, and confirm the data shape matches your expectations.

Fixing broken JSON — when a JSON string is failing to parse in your application, paste it here to find the exact syntax error.

Config file editing — format configuration files (package.json, tsconfig.json, Terraform output) before editing to make the structure clear.

Learning JSON structure — see how nested objects, arrays, and different value types are represented and formatted.

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Privacy

All formatting and validation happens in your browser. No JSON data is sent to any server or stored anywhere.