JSON Formatter
Format, validate and minify JSON data
How to use JSON Formatter
Format, validate and minify JSON data with syntax highlighting. Detect errors instantly. Free online JSON formatter and validator.
What is JSON formatting used for?
JSON (JavaScript Object Notation) is the standard data exchange format for web APIs, configuration files, and data storage. Raw JSON from APIs is often minified — compressed into a single line — making it unreadable. Formatting adds indentation and line breaks to make the structure clear.
Common uses:
- API debugging: Paste a raw API response and instantly see the structure, nested objects and arrays in a readable format.
- Configuration files: Validate and format JSON config files for applications like VS Code settings, package.json or eslint.
- Data exploration: When working with large datasets, formatting helps identify the shape and nesting of data before writing code.
- Error detection: The validator highlights syntax errors — missing commas, unmatched brackets, invalid values — before they cause runtime bugs.
- Minification: Remove all whitespace to reduce payload size before sending data over a network or storing it.
Example: {"name":"Alice","age":30} becomes clearly structured with proper indentation, making nested objects like {"address":{"city":"Barcelona","zip":"08001"}} immediately readable.
Frequently Asked Questions
What is the difference between JSON and JavaScript objects?
JSON is a text format based on JavaScript object syntax, but it is stricter: keys must be quoted with double quotes, trailing commas are not allowed, and functions or undefined values are not permitted. JavaScript objects are more flexible and only exist in memory.
Why does my JSON show a syntax error?
Common causes: a trailing comma after the last item, single quotes instead of double quotes, an unescaped special character in a string, or a missing closing bracket or brace. The formatter will highlight the exact position of the error.
What is JSON minification?
Minification removes all unnecessary whitespace, newlines and indentation from JSON, reducing file size. A 10KB formatted JSON might become 6KB minified — useful for API responses and reducing bandwidth.
Is JSON5 the same as JSON?
No. JSON5 is an extension that allows comments, single quotes and trailing commas. Standard JSON parsers cannot parse JSON5. Always use standard JSON for APIs and data exchange.
Can JSON store binary data?
Not directly. Binary data must be encoded as a Base64 string before including it in JSON. This increases size by about 33% but ensures compatibility with all JSON parsers.
JSON vs other data formats
JSON is human-readable, universally supported and the default for web APIs. XML is more verbose but supports attributes and namespaces — still used in enterprise systems and SOAP APIs. YAML is cleaner for configuration files (used in Docker, Kubernetes) but whitespace-sensitive and error-prone. CSV is ideal for tabular data but cannot represent nested structures. MessagePack and Protocol Buffers are binary formats — faster and smaller but not human-readable. For web APIs, JSON is the clear standard.