Codex for Beginners

You have 168 short lessons ahead of you.

Start for free Review the flashcards

Modules 00 and 01 are free, in full. No card needed.

Codex is included even in the free ChatGPT plan, in the desktop app, but access there is rolling out gradually, so you may not have it yet. The phone, the cloud, the terminal and VS Code (modules 10–12) need at least ChatGPT Plus ($20/month). Checked on OpenAI’s official page, 8 October 2026.

  1. 00. Welcome to Codex0 / 12 lessonsWelcome to CodexStart
  2. 01. Installation and your first project0 / 12 lessonsInstallation and your first project
  3. 02. A tour of the app0 / 12 lessonsA tour of the app
  4. 03. How to talk to Codex0 / 12 lessonsHow to talk to Codex
  5. 04. Check, save, undo0 / 12 lessonsCheck, save, undo
  6. 05. Permissions and safety0 / 12 lessonsPermissions and safety
  7. 06. Cost, context and parallel work0 / 12 lessonsCost, context and parallel work
  8. 07. AGENTS.md: the project rules0 / 12 lessonsAGENTS.md: the project rules
  9. 08. Skills, plugins and MCP0 / 12 lessonsSkills, plugins and MCP
  10. 09. Scheduled tasks and hooks0 / 12 lessonsScheduled tasks and hooks
  11. 10. Codex on your phone and in the cloud0 / 12 lessonsCodex on your phone and in the cloud
  12. 11. Codex in the terminal, without fear0 / 12 lessonsCodex in the terminal, without fear
  13. 12. Codex in VS Code0 / 12 lessonsCodex in VS Code
  14. 13. Teamwork, troubleshooting and the final project0 / 12 lessonsTeamwork, troubleshooting and the final project
  15. The Codex series

    14 modules, 168 short lessons. One poster per module; the folded corner shows where you left off.

What you build

Eight labs, to do on your laptop, in the ChatGPT desktop app. Step by step you build “Subscriptions under control”, an app that shows what your subscriptions cost and what renews soon. The first lab is free.

  1. L0First version: your subscription listAfter module 01, Installation and your first project
  2. L1Add, edit, delete, without losing anythingAfter module 03, How to talk to Codex
  3. L2Save points and undoAfter module 04, Check, save, undo
  4. L3CSV import and calendar remindersAfter module 05, Permissions and safety
  5. L4House rules: AGENTS.mdAfter module 07, AGENTS.md: the project rules
  6. L5Your first skill: the monthly reportAfter module 08, Skills, plugins and MCP
  7. L6An automatic report every MondayAfter module 09, Scheduled tasks and hooks
  8. L7On GitHub, in the cloud and on your phoneAfter module 10, Codex on your phone and in the cloud

Who it’s for

  • People who have never written code and want to build a small app they’ll use every day.
  • People who already use ChatGPT and want to go from conversations to things that actually run on their computer.
  • People who took the Claude Code course and want to work with OpenAI’s agent too: the same ideas, a different tool.

At a glance

The lessons
2 h 57 min168 lessons of 1–2 minutes, which you can also read on your phone.
The labs
6–8 h8 labs on your laptop, 30–90 minutes each. You go at your own pace.
The whole course
€39One-time payment. A single module costs €9. All prices.

What you need

  • A laptop or desktop with Mac or Windows, where you install the ChatGPT desktop app. You can read the lessons on your phone too; the labs are done on the computer.
  • A ChatGPT account. The free plan is enough to get started, with lower limits, but access to Codex on it is rolling out gradually. For the phone, the cloud, the terminal and VS Code (modules 10–12) you need at least ChatGPT Plus, $20/month. You’ll find the plans on OpenAI’s official page.
  • No coding experience. Every technical word is explained, and the glossary has all of them.

Questions

Do I need to know how to code?

No. You tell Codex what you want in ordinary words, and it writes the code. You learn to ask well, to check what it did and to undo what you don’t like.

Do I need to have taken the Claude Code course?

No. The Codex course starts from zero. If you’ve already taken the Claude Code course, many ideas will feel familiar and you’ll move faster.

Do I pay for anything else besides the course?

Not necessarily: Codex is included even in the free ChatGPT plan, in the desktop app, with lower limits; access there is rolling out gradually, so you may not have it yet. For modules 10–12 (phone, cloud, terminal, VS Code) you need at least ChatGPT Plus, $20 a month, from OpenAI. The course itself you pay for once; it’s not a subscription.

What do I get for free?

Modules 00 and 01, in full: the lessons, questions, tests and flashcards, plus the first lab, where you build the first version of the app. No card needed.

What if I don’t like it?

You have 14 days from purchase to ask for your money back, without giving a reason, straight from your account. If you bought the whole course and started at most 2 paid modules, you get all your money back. The details are in the refund policy.

How long do I have access?

Access to what you buy doesn’t expire. The whole course also includes the modules that come out from now on, at no extra cost.

Andrei Stici, with short hair, in a navy turtleneck sweater, holding a pen

Who’s teaching you

I’m Andrei Stici. I’ve been working with AI for two years and built this very site with an AI agent. I adapted the Codex course for beginners from the open-source CodexGuide and checked it against OpenAI’s official documentation.

More about me