JSON Format: A Complete Guide for Developers

JSON (JavaScript Object Notation) is the most widely used data interchange format on the web. It is human-readable, lightweight, and supported by virtually every programming language.

JSON Syntax Rules

JSON supports six data types: strings (in double quotes), numbers, booleans (true/false), null, arrays (ordered lists), and objects (key-value pairs). Keys must be strings in double quotes. Trailing commas are not allowed.

Common JSON Mistakes

The most frequent errors include using single quotes instead of double quotes, adding trailing commas after the last item, including comments (JSON does not support comments), and using undefined or NaN values. Our JSON Validator catches all of these errors with clear messages.

JSON vs XML

JSON is more compact than XML, easier to read, and faster to parse. XML supports attributes, comments, and namespaces, which JSON does not. For web APIs, JSON has largely replaced XML as the standard format.

Working with JSON

Most languages provide built-in JSON parsing. In JavaScript, use JSON.parse() to read and JSON.stringify() to write. Python uses the json module. In both cases, always handle parse errors gracefully.

Pretty Printing

Formatted JSON with proper indentation is essential for readability during development. Use our JSON Formatter to beautify minified JSON instantly. For production, minified JSON reduces bandwidth.