JSON Formatter & Validator
Paste messy JSON, get clean formatted output with syntax highlighting and validation. Minify or pretty-print with one click.
JSON Formatter
Paste your JSON to format, validate, or minify it.
Formatted JSON will appear here
How it works
JSON (JavaScript Object Notation) is the lingua franca of modern APIs. This tool parses your input using the browser's native JSON.parse(), then re-serializes it with your chosen indentation.
Syntax highlighting is applied via simple pattern matching on the serialized output: keys are colored amber, strings emerald, numbers use the brand color, booleans violet, and null values are dimmed. No external libraries are loaded.
Minify strips all whitespace to produce the smallest possible JSON string, useful for reducing payload size in API calls or configuration files.
FAQ
- What is JSON?
- JSON (JavaScript Object Notation) is a lightweight data interchange format that is easy for humans to read and write and easy for machines to parse and generate. It is the most common format for APIs and configuration files.
- How do I validate JSON?
- Paste your JSON into the input area and click Format. If the JSON is invalid, you will see an error message describing the problem. Valid JSON will be formatted with proper indentation and syntax highlighting.
- What is the difference between JSON and XML?
- JSON is more concise, easier to read, and natively supported by JavaScript. XML supports attributes, namespaces, and comments, making it more verbose but more expressive for certain use cases like document markup.
- What are common JSON errors?
- Trailing commas after the last item, single quotes instead of double quotes, unquoted keys, missing commas between items, and comments (JSON does not support comments). These are the most frequent causes of invalid JSON.
- Is my data safe?
- Yes. All formatting and validation happens entirely in your browser. No data is sent to any server. You can verify this by disconnecting from the internet and using the tool offline.
- Can I format large JSON files?
- Yes, the formatter works with large JSON payloads. However, extremely large files (tens of megabytes) may cause your browser tab to slow down since all processing happens client-side.
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