OpenAI's coding agent, in your terminal, your editor and the cloud. Built by OpenAI.
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Common questions
Is Codex CLI free to use?
Codex CLI is open source and free to run yourself. You still pay whichever model provider you point it at, and this tutorial is free with no signup.
Do I need to know Python to use Codex CLI?
Basic Python is enough. Functions, dictionaries and imports cover most of what Codex CLI asks of you.
When should I not use Codex CLI?
When something else in coding agent fits the job better. The others in that group are listed below.
Lessons for Codex CLI are being written. Meanwhile the Claude Code tutorial covers the same ground: state, tools, loops, memory and human approval. Most of it carries straight over.
Start the Claude Code tutorial →