What is GitHub Copilot?

GitHub Copilot is an AI-powered coding assistant developed by GitHub in partnership with OpenAI. It acts as your "AI pair programmer," suggesting code completions, entire functions, and even complex algorithms as you type.

How GitHub Copilot Works

Copilot uses a large language model (LLM) trained on billions of lines of public code from GitHub repositories. When you write code, Copilot analyzes:

• Your current file - The code you've already written
• Open files in your editor - Related code for context
• Your comments and function names - Natural language descriptions of what you want
• The programming language - Syntax and conventions specific to that language

Based on this context, Copilot predicts what you're likely to write next and offers suggestions in real-time.

Key Features

Inline Code Suggestions

As you type, Copilot shows ghost text suggestions that you can accept with a single keystroke. These range from completing a variable name to generating entire functions.

// Example: Type a comment and Copilot suggests the implementation
// Function to calculate the factorial of a number
function factorial(n) {
  if (n <= 1) return 1;
  return n * factorial(n - 1);
}

Copilot Chat

Beyond code completion, Copilot Chat lets you have conversations about your code. You can ask it to:

• Explain what a piece of code does
• Suggest refactoring improvements
• Help debug errors
• Generate documentation

Multi-Language Support

Copilot works with virtually any programming language, but excels particularly in:

• JavaScript/TypeScript
• Python
• Java
• C/C++
• Go
• Ruby
• PHP
• C#

Copilot Plans and Pricing

GitHub offers several Copilot subscription tiers:

Plan	Price	Best For
Copilot Free	$0/month	Trying Copilot with limited completions
Copilot Pro	$10/month	Individual developers
Copilot Business	$19/user/month	Teams and organizations
Copilot Enterprise	$39/user/month	Large enterprises with advanced features

Free for students and open source maintainers: If you're a verified student or maintain a popular open source project, you may qualify for free Copilot access.

What Copilot Can and Cannot Do

Copilot Excels At

• Writing boilerplate code quickly
• Implementing common patterns and algorithms
• Converting comments to code
• Generating repetitive code structures
• Writing tests based on existing code
• Creating documentation

Copilot Limitations

• It doesn't truly "understand" code - it predicts based on patterns
• It can suggest outdated or insecure code patterns
• It may not know about your specific codebase's conventions
• Complex business logic often needs significant human review
• It can "hallucinate" APIs or methods that don't exist

The AI Pair Programming Philosophy

Think of Copilot as a very fast but sometimes unreliable junior developer. It can:

• Draft code quickly for you to review
• Handle tedious boilerplate
• Suggest approaches you might not have considered

But you should always:

• Review suggestions before accepting
• Test the generated code
• Understand what the code does before using it
• Never blindly trust security-sensitive code

Summary

GitHub Copilot is a powerful AI assistant that can significantly speed up your coding workflow. It analyzes your code context and suggests completions in real-time. While it excels at common patterns and boilerplate, it requires human oversight to ensure code quality, security, and correctness.

In the next lesson, you'll learn how to set up Copilot in your preferred IDE and configure it for your workflow.