JSON
JavaScript Object Notation
A lightweight data format for exchanging data between systems
In Simple Terms
JSON is a lightweight, human-readable format that computers use to exchange data with each other. For example, it's used in all kinds of situations — like when a smartphone app receives information such as "today is sunny and 25°C" from a weather server, when a social media app loads your timeline, or when a game saves your score.
Behind the Name
JSON is short for JavaScript Object Notation. JavaScript is the name of a programming language, Object means a bundle of data, and Notation means a way of writing or representing something. A direct translation would be "a way of writing JavaScript data." It got this name because it was modeled after the object syntax used in JavaScript.
Take a Closer Look!
JSON is a set of rules for representing data as text.
It's easy for humans to read and understand, while also being simple for computer programs to process.
Because it can be easily read and written in a wide variety of programming languages — including Python and Java — it has been widely adopted as a standard data exchange format for systems built in different languages to communicate with each other over the internet.
The syntax is very simple.
Data is represented as name-value pairs connected by a colon. The most common form wraps the whole thing in curly braces. For arrays, where multiple values are listed in order, square brackets are used.
When there are multiple entries, they are separated by commas.
For example, data representing "name is Taro, age is 20" would be written as {"name": "Taro", "age": 20}.
Compared to formats like XML, JSON uses fewer unnecessary symbols, which keeps the overall data size small.
As a result, data can be sent and received more quickly over the internet.