In web development, what is JSON and how is it commonly used to exchange data between a browser and a server?

Introduction / Context:
JSON is one of the most widely used formats for sending structured data in modern web applications. It appears in REST APIs, configuration files, and client side scripting. Interviewers expect candidates to know not only what the acronym stands for but also why it became so popular in comparison with older formats. This question checks whether you understand JSON as a data interchange format and not as a database language or markup language.

Given Data / Assumptions:

• We are dealing with data sent between a browser and a web server.
• The data needs to represent objects, arrays, and simple values.
• The format must be simple to parse in JavaScript and other languages.
• We are considering standard usage in web services and AJAX calls.

Concept / Approach:
JSON stands for JavaScript Object Notation. It is a text based format that represents data in key value pairs (also called name value pairs) and arrays. The syntax closely mirrors literal object notation in JavaScript, which makes it natural for browsers to parse and generate. At the same time, many other languages provide libraries to handle JSON, making it a common choice for server client communication. Because it is text based and language independent, it is easy to log, debug, and inspect.

Step-by-Step Solution:
Step 1: Recall that JSON uses curly braces for objects and square brackets for arrays, with keys written as strings and values as strings, numbers, booleans, null, objects, or arrays. Step 2: Recognize that this structure is ideal for representing hierarchical data such as user profiles, configuration settings, or responses from an API. Step 3: Understand that JSON is not a binary image format, a database query language, or a physical file system. Step 4: Compare the options and see that option a correctly describes JSON as a lightweight, text based data interchange format used between browser and server. Step 5: Eliminate the other options as they describe unrelated technologies.

Verification / Alternative check:
In practice, when you inspect network traffic from a modern web application using browser developer tools, you will often see responses such as {"name":"Alex","age":30} returned from REST endpoints. This is JSON data. The client side code then uses JSON.parse to convert it into a JavaScript object. Server side frameworks in languages like Java, Python, and PHP also provide functions to encode and decode JSON. This confirms that JSON is a general data interchange format and not simply a niche technology.

Why Other Options Are Wrong:
Option b refers to an image format, which does not match JSON syntax or usage. Option c sounds like Structured Query Language, which is used with relational databases, not JSON. Option d suggests a file system, which is not what JSON provides. Option e calls JSON a markup language that can only describe layout, which is incorrect; JSON is not primarily for layout and is not a traditional markup language like HTML.

Common Pitfalls:
One pitfall is to treat JSON as if it allowed comments and arbitrary syntax; the standard format is strict and does not allow comments by default. Another mistake is to confuse JSON with JavaScript code and attempt to include functions, which are not part of valid JSON. Keeping in mind that JSON is a simple, language independent representation of structured data helps avoid these errors.

Final Answer:
JSON is a lightweight text based data interchange format using name value pairs and arrays, commonly used to move structured data between a browser and a server, as stated in option a.