JavaScript Object Notation

What Does JavaScript Object Notation Mean?

JavaScript Object Notation (JSON) is an open standard data exchange format based on a JavaScript syntax subset. JSON is text-based, lightweight, and generally considered easily readable/writeable.


Although closely connected to JavaScript, JSON is language-independent. Though independent, JSON uses conventions similar to other languages (e.g., C, C++, Java, Perl and Python), making JSON an ideal data-exchange language.

JSON characteristics include the following:

  • Flexibility, allowing the programmer to define keys.
  • Less overhead, as content is mostly data.
  • Portable data.
  • Non-proprietary.
  • Common and convenient format for Web services.

Commonly utilized in Web application development, JSON may be used as a data format for any application where information is stored as text.

Techopedia Explains JavaScript Object Notation

JSON is preferred by some over XML as a data exchange format because it is less verbose, works quickly, reduces data size and simplifies document processing. It is used extensively in web development, especially because it seamlessly transfers information between potentially incompatible technologies. For example, it could involve a Java application running on a UNIX box or a C# application running on Windows.

Certain precautions are advised as JSON is prone to security issues derived from JavaScript’s interpreter and object literals, which dynamically execute JSON text as JavaScript. In other words, JSON is vulnerable to JavaScript insertion attackers, who can hack and extract system/Web server content and transmitted application objects. JSON security-enhancing techniques do exist and can resolve such issues. Thus, before implementing JSON, developers should continually be aware of all security loopholes and possible solutions.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.