{}JSON Formatter

Free Online JSON Formatter

Format, minify, validate, and explore JSON data with syntax highlighting and interactive tree view. Detect errors with precise line numbers.

The JSON is processed in your browser without sending it to ToolsFree. Remove secrets before pasting sensitive configuration.

Available features

Pretty print with configurable indentation, minification, validation with detailed errors, collapsible tree view, JSON statistics, download and copy.

Common JSON Errors

Working with JSON can be frustrating when hard-to-find syntax errors appear. The most common issues include trailing commas: unlike JavaScript, JSON does not allow a comma after the last element of an array or object. Single quotes are also invalid in JSON; all strings and keys must use double quotes. Forgetting to quote object keys is another frequent mistake, since JSON requires all keys to be quoted strings. Unescaped control characters inside strings, such as literal newlines or tabs, also cause errors; they must be written as \n and \t respectively. Our validator detects all of these issues and shows the exact line number where the error is located.

JSON vs XML

JSON and XML are the two most widely used formats for structured data exchange. JSON stands out for its lightweight and readable syntax, native integration with JavaScript, smaller file sizes, and ease of parsing. It is the standard format for REST APIs, modern application configurations, and data storage in NoSQL databases like MongoDB. XML, on the other hand, offers support for more powerful validation schemas (XSD), namespaces, comments, and element attributes. It remains widely used in SOAP services, document formats like SVG and XHTML, and in industries with established XML standards such as banking (ISO 20022) and healthcare (HL7). In general, if you are building a modern web API or storing configurations, JSON is the better choice. If you need strict schema validation or work with legacy enterprise standards, XML may be more appropriate.