What is Claude Code?

Claude Code is an agentic coding tool that lives in your terminal. It can read your codebase, write code, run commands, and help you build entire applications through natural conversation.

What makes it different?

Unlike chat-based AI tools where you copy-paste code back and forth, Claude Code:

• Reads your entire project — it understands your codebase structure, dependencies, and patterns
• Writes files directly — no copy-pasting needed
• Runs commands — it can install packages, run tests, start dev servers
• Learns your project — through CLAUDE.md files that persist context across sessions
• Runs on different models — use Sonnet for speed on routine tasks, or Opus for complex reasoning. Switch anytime with the /model command.

Claude web vs Claude Code

If you've used Claude at claude.ai, you've been using Claude web — a chat interface where you type a question and get a response. Claude Code uses the same AI brain, but it works completely differently:

	Claude web	Claude Code
Where it runs	In your browser	In your terminal, inside your project
Sees your code	Only what you paste in	Reads your entire codebase automatically
Edits files	You copy-paste suggestions back	Writes and modifies files directly
Runs commands	Can't	Installs packages, runs tests, starts servers
Remembers your project	Forgets between conversations	CLAUDE.md persists context across sessions
Best for	Questions, writing, analysis	Building, debugging, shipping code

Think of it this way: Claude web is like texting a smart friend for advice. Claude Code is like that friend sitting next to you, hands on the keyboard, building it with you.

What we'll build

In this course, you'll build a full-featured todo application using Claude Code as your AI pair programmer. By the end, you'll have:

• A complete Next.js app with CRUD operations
• Categories, priorities, due dates, and search
• Beautiful UI with dark mode and animations
• Tests, database integration, and deployment

Let's get started.