As compared to XML, JSON is smaller, lightweight, faster and easier to parse. JSON is “self-describing” and easy to understand.

- Number: double-precision floating-point format in JavaScript, generally depends on implementation.
- String: double-quoted Unicode, with backslash escaping.
- Boolean: true or false
- Array: an ordered, comma-separated sequence of values enclosed in square brackets; the values do not need to be of the same type.
- Object: an unordered, comma-separated collection of key: value pairs enclosed in curly braces, with the ‘:’ character separating the key and the value; the keys must be strings and should be distinct from each other
- Null: empty
JSON is frequently used in Ajax techniques.
Some of the noteworthy applications that we have developed using XML
JSON Schema: JSON Schema specifies a JSON-based format to define the structure of JSON data for validation, documentation, and interaction control. A JSON Schema provides a contract for the JSON data required by a given application, and how that data can be modified. JSON Schema is based on the concepts from XML Schema, RelaxNG, and Kwalify, but is JSON-based. The JSON data schema can be used to authenticate JSON data; the same serialization/deserialization tools can be used both for the schema and data. The schema is self-describing. JSON Schema is an Internet Draft, currently version There are several validators available for different programming languages, each with varying levels of conformance.
MIME type: The official MIME type for JSON text is “application/json”. Although most modern implementations have adopted the official MIME type, many applications continue to provide legacy support for other MIME types. Many service providers, browsers, servers, web applications, libraries, frameworks, and APIs use, expect, or recognize the (unofficial) MIME type “text/json” or the content-type “text/javascript”. Notable examples include the Google Search API, Yahoo!, Flickr, Facebook API, Lift framework, Dojo Toolkit 0.4, etc.
JSON-RPC: JSON-RPC is an RPC protocol built on JSON, as a replacement for XML-RPC or SOAP. It is a simple protocol that defines only a handful of data types and commands. JSON-RPC allows for notifications and for multiple calls to be sent to the server that may be answered out of order.