OpenAI Codex is a very helpful tool in modern software development, but getting real value from it comes down to understanding how it is actually meant to be used. To help developers master its core capabilities, we just released a complete, hands-on beginner’s course on the freeCodeCamp.org YouTube channel.
The tutorial walks you through everything from the ground up, starting with installation, pricing tiers, and a comprehensive tour of the interface. You will learn how to run scheduled background automations, manage external context with tools like Notion and Supabase, and handle GitHub pull requests directly within the environment. It also teaches Codex’s most powerful operating paradigms: switching between Plan Mode (where the agent iteratively questions assumptions and outlines architecture) and Go Mode (where it autonomously drives an MVP to completion).
To put these concepts into practice, the course demonstrates building a full, voice-controlled Flappy Bird-style game entirely through Codex prompts. You will see the complete development lifecycle in action: iterative prompt refinement, instant browser deployment via built-in hosting, and testing microphone input directly in the app. Finally, the video covers how to take the open-source repository and convert the project into a native iOS and Android mobile app using Expo.
Watch the full course on the freeCodeCamp.org YouTube channel.