Codex

What it does

Codex is OpenAI’s coding agent. You describe a task, such as fixing a bug or adding a feature, and it reads your code, makes the changes and runs commands to check its work.

It works in your terminal (Codex CLI), in editors such as VS Code and Cursor, as a desktop app, and as a cloud agent at chatgpt.com/codex. It comes with paid ChatGPT plans and is made for developers.

Why use it

• It comes with ChatGPT Plus, Pro, Business, Edu and Enterprise plans.
• The same agent works in your terminal, your code editor, a desktop app and the cloud.
• The command-line tool is open source, so anyone can inspect how it works.

How it works

1. Sign in with a paid ChatGPT account, or set up an OpenAI API key.
2. Install the command-line tool or the editor extension, or open chatgpt.com/codex.
3. Open the project you want to work on.
4. Describe the task in plain English.
5. Review and test its changes before you keep them.

How hard is it to use?

Advanced Made for people at home with technical tools, or ready to learn them.

Made for developers: you need to read and judge code, and be comfortable in a terminal or code editor, which is why we rate it Advanced.

What it costs

Included with paid ChatGPT plans. It comes with paid ChatGPT plans: Plus, Pro, Business, Edu and Enterprise. You can also use it with an OpenAI API key and pay for what you use.

Prices change often, so check Codex’s own site before you pay.

Watch out for

• Review its changes carefully: they can look right and still contain bugs.
• Heavy use can hit your plan’s limits, and API use is charged by how much you use.
• Check your organisation’s rules before you connect work code or repositories.

Your data

Before you use it on private code, check the data controls in your ChatGPT settings and your plan’s terms to see whether your code can be used to train OpenAI’s models.

We haven’t confirmed that Codex can keep your data in the UK, so check where it keeps your data before you share anything private or about other people.