Introduction to GitHub Copilot
Introduction to GitHub Copilot
GitHub Copilot is the AI pair programmer built directly into your editor. Unlike using ChatGPT in a browser tab and copying code back and forth, Copilot lives where you write code — suggesting the next line, answering questions in a chat panel, and applying multi-file changes without you leaving VS Code or JetBrains.
A brief history
GitHub Copilot launched in 2021 as a technical preview, powered by OpenAI Codex. It was the first mainstream AI coding tool. Since then it has expanded dramatically: Chat mode, Copilot CLI for the terminal, PR summaries on GitHub.com, and Copilot Workspace for agent-style task completion. As of 2024–2025, Copilot is powered by newer OpenAI and custom models and is one of the most widely adopted developer tools in the world.
Who uses Copilot and why
- Professional engineers use it daily for boilerplate, tests, and repetitive CRUD code. Time savings on routine tasks compound over a year.
- Learners use it as an interactive tutor. Ask it to explain code, suggest alternatives, or generate examples of a pattern you are studying.
- Code reviewers use it on GitHub.com to understand unfamiliar changes and spot potential issues.
- DevOps / platform engineers use the CLI to get shell commands without memorizing arcane syntax.
A Copilot certificate shows that you know how to use this tool effectively — not just that you have enabled the extension, but that you understand how to prompt it well, review its output, and integrate it into a professional workflow.
The three surfaces
Copilot appears in three main places:
1. Inline completion (editor) Gray text appears as you type. Press Tab to accept. This is the fastest mode — you barely notice it after a while, and it just makes you faster.
2. Copilot Chat (editor panel) A conversation interface docked to the side of your editor. You attach files or selections, ask questions, request refactors, and apply suggested code. This is where the deeper AI-assisted workflows happen.
3. GitHub.com integration PR summaries, code review assistance, issue comments, and Copilot Workspace for turning issues into pull requests.
What makes Copilot different from ChatGPT
| ChatGPT / Claude (browser) | GitHub Copilot (editor) | |
|---|---|---|
| Where you use it | Browser tab, separate window | Inside VS Code or JetBrains |
| Code context | Whatever you paste | Current file + open tabs automatically |
| Applying changes | Copy-paste manually | "Apply" button inserts directly |
| Commit/PR integration | None | GitHub.com PR summaries, reviews |
| CLI support | None | gh copilot suggest for terminal |
Copilot and browser-based chat tools complement each other. Many developers use both: Copilot for in-editor work and something like Claude for design discussions, large-scale explanations, or tasks that need a wider context than the current file.
What you will learn in this track
This course has ten lessons covering everything from installation to advanced prompting. By the end you will:
- Understand how Copilot works under the hood (context windows, training cutoffs, why it makes mistakes).
- Install and configure Copilot correctly for your editor and project.
- Use inline completion efficiently — knowing when to accept, cycle through alternatives, or ignore.
- Use Chat for explanations, debugging, refactoring, and code generation.
- Use Workspace-style features for multi-file tasks.
- Use Copilot CLI, PR summaries, and code review tools on GitHub.com.
- Write prompts that consistently produce correct, idiomatic code.
- Use Copilot for tests, documentation, and code review.
- Know when to trust output and when to verify carefully.
- Work within security and privacy constraints.
Let's start with how the technology actually works.