Structure:

• JSON: Key-value pair.
• XML: Hierarchical with nested elements.

Example:

JSON:

                    
{
  "book": {
    "title": "Learning JSON",
    "author": "Jane Doe",
    "price": 19.99
  }
}
                    
                  

XML:

                    
<book>
  <title>Learning JSON</title>
  <author>Jane Doe</author>
  <price>19.99</price>
</book>
                    
                  

Pros and Cons of Using JSON and XML:

JSON:

Pros:

• Easier to read and write.
• More compact so uses less bandwidth.
• Native in JavaScript and many other languages.

Cons:

• No comments.
• Not as good for complex data structures.

XML:

Pros:

• Very flexible and supports complex data structures.
• Can include metadata through attributes.
• Supports comments within the data.

Cons:

• More verbose so larger data sizes.
• Slightly more complex to parse and write.

When to Use JSON and When to Use XML:

Use JSON:

• When you need a light and easy to read format.
• For web applications especially when using JavaScript.
• When you need to transfer data over the network quickly.

Use XML:

• When you need to include metadata with your data.
• For documents that requires complex structures.
• When working with systems that requires XML, such as SOAP web services.