JSON & APIs

JSON (JavaScript Object Notation) is a lightweight data format used everywhere on the web. It supports six data types:

• Strings — wrapped in double quotes: "hello"
• Numbers — integers or decimals: 42, 3.14
• Booleans — true or false
• Arrays — ordered lists: [1, 2, 3]
• Objects — key-value pairs: {"name": "Alice"}
• Null — empty value: null

Edit the JSON below, then click Validate to check if it's valid:

JSON structures can be deeply nested. Objects contain objects, arrays contain objects, and so on. To access nested data in JavaScript:

• data.key — access an object property
• data.array[0] — access an array element by index
• data.users[0].name — chain them to go deeper

Try parsing the JSON string and accessing nested properties:

REST APIs use HTTP methods to perform actions on resources. The most common:

• GET — retrieve data (e.g., GET /api/users)
• POST — create new data (e.g., POST /api/users)

Try the mock API below — choose a method, enter a path, and send a request:

1. Which of these is valid JSON?

2. How do you access the second element of a JSON array?

3. Which HTTP method is used to retrieve data from a REST API?