What is Codex, really?
Welcome to Codex · lesson 2 of 12
Codex is the coding agent made by OpenAI, the company behind ChatGPT. An agent is an AI that doesn’t stop at an answer: it takes concrete steps. It opens files, writes code, runs commands (written instructions for the computer) and checks what came out.
Code is the text of instructions an app is made of. You don’t have to write it, or understand it line by line. You describe the result, Codex does the work, and you check it.
How it differs from an ordinary chat:
- In a chat you get an answer and copy what you need yourself.
- With Codex you pick a folder on your computer, and it works right there.
- A chat tells you how it could be done. Codex actually does it, then shows you what it changed.
Switch between the two versions:
Like a chat
> how do I make a page with my subscriptions?
● Here’s some example code. Copy it into a file called index.html…
⎿ You get a block of code that you save by hand
= The work stays with you: you copy, save, open and fix it yourself.
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With Codex
> Make me a page with my subscriptions and the monthly total.
● I’m creating index.html in the project folder with 5 examples…
⎿ Created index.html. Monthly total: €62.
= Codex works directly in your folder. You just check the result.