Getting Started with JSON: A Developer's Guide

JSON (JavaScript Object Notation) has become the de facto standard for data interchange on the web. Whether you’re building a REST API, configuring a VS Code project, or storing NoSQL data, you’ll encounter JSON.

In this guide, we’ll cover:

1. What JSON is and why we use it.
2. Syntax rules you must follow.
3. Common pitfalls and how to avoid them.

What is JSON?

JSON stands for JavaScript Object Notation. It is a lightweight data-interchange format that is easy for humans to read and write, and easy for machines to parse and generate.

Despite its name, JSON is language-independent. Code for parsing and generating JSON data is readily available in many programming languages.

JSON Syntax Rules

JSON syntax is derived from JavaScript object notation syntax:

• Data is in name/value pairs
• Data is separated by commas
• Curly braces hold objects
• Square brackets hold arrays

Example

{
  "name": "John Doe",
  "age": 30,
  "isDeveloper": true,
  "languages": ["JavaScript", "Python", "Rust"],
  "address": {
    "street": "123 Main St",
    "city": "New York"
  }
}

Common Mistakes

1. Trailing Commas

JSON does not allow trailing commas. This is valid in JavaScript but invalid in JSON.

Invalid:

{
  "name": "John",
}

Valid:

{
  "name": "John"
}

2. Single Quotes

Strings and property names must be enclosed in double quotes. Single quotes are not allowed.

Invalid:

{
  'name': 'John'
}