How to Set Up and Run OpenAI Codex CLI on Windows: A Step-by-Step Guide

In this guide, I’ll walk you through the process of setting up and running OpenAI Codex CLI on your Windows machine. Whether you’re a developer or a tech enthusiast, this powerful tool can help you integrate Codex into your workflow, automate coding tasks, and even generate code directly from natural language prompts. So, let’s get started!

Why Use OpenAI Codex CLI?

OpenAI Codex is an AI model developed to assist with coding by understanding natural language and generating code snippets, comments, and even entire applications. By setting up the Codex CLI (Command-Line Interface), you gain direct access to Codex’s capabilities, making it easier to integrate AI into your coding projects. This is particularly useful for automating repetitive coding tasks or learning new programming concepts.

Prerequisites: Install Node.js

Before you can use OpenAI Codex CLI, you must have Node.js installed on your Windows machine, as Codex CLI is distributed as an npm (Node Package Manager) package. If you don’t have Node.js installed, follow these steps to set it up.

Steps to Install Node.js:

1. Download Node.js:
   • Visit the official Node.js website by searching “NodeJS” on Google, or go directly to https://nodejs.org.
   • Download the latest stable version of Node.js (currently version 22). You can also download an older version if required.
2. Install Node.js:
   • Run the downloaded .msi installer (about 29 MB in size).
   • Follow the installation prompts: accept the license agreement, choose the default installation location, and click “Next” until the installation begins.
3. Verify Installation:
   • Open your Command Prompt (CMD) and check if Node.js was installed successfully by typing the following commands: node -v npm -v
   • These commands will show the installed versions of Node.js and npm (Node Package Manager).

Step 1: Install OpenAI Codex CLI

Now that Node.js is installed, you can easily install OpenAI Codex CLI via npm.

Run the Installation Command:

1. Open your Command Prompt (CMD) and run the following command:
2. npm install -g @openai/codex
3. Wait for the installation to complete. Once finished, you’re ready to interact with the Codex CLI.

Step 2: Set Up Your OpenAI API Key

To access Codex models, you’ll need to set your OpenAI API key. If you don’t have an OpenAI API key, follow these steps to generate one:

1. Go to the OpenAI Platform and sign up (if you haven’t already).
2. Once logged in, navigate to API Keys and generate a new secret key. Make sure to copy the key.

Set the API Key in the Terminal:

1. In your terminal, enter the following command (replacing YOUR_API_KEY with the actual key): set OPENAI_API_KEY=YOUR_API_KEY
2. If you need to set the key globally, you can add it to your system’s environment variables for persistent access.

Step 3: Run OpenAI Codex CLI

Now that everything is set up, you can run the Codex CLI. Just type codex in your terminal, and you’ll see the Codex interface:

codex

The CLI will prompt you to choose which model to use. You can interact with Codex using natural language commands and it will generate code accordingly. Here are a few things you can do:

• Type /help to get a list of available commands.
• Use /model to see all the Codex models available.
• Start coding by giving prompts such as “Create an HTML app that can convert input image to multiple styles.”

Step 4: Test Codex with a Sample Prompt

Let’s see Codex in action. Here’s a simple example:

1. In the Codex CLI, type the following prompt: Can you create an HTML app that can convert an input image to multiple styles and allow me to download it?
2. Codex will take a moment to process your request and generate a complete solution, including HTML, CSS, and JavaScript code. You can edit or iterate on this solution by typing “Yes” or providing further feedback.
3. The output will be a fully functional app with an HTML file, where you can upload an image and apply multiple styles. You can even download the modified image directly.

Integrating Codex with Your React Project

If you have an existing project, such as a React app, you can easily integrate Codex into it. Here’s how:

1. Navigate to the root directory of your React project in the terminal.
2. Run the codex command. If you’ve already set the API key, it will work without issues.
3. Ask Codex to explain or modify the code in your React project. Codex will automatically list the files and provide insights into the codebase.

For instance, you can ask Codex to explain the structure of your React app or make code modifications directly.

You can get to know from Github.

Conclusion

Setting up and running OpenAI Codex CLI on Windows is a straightforward process that allows you to unlock the full potential of Codex in your development workflow. Whether you’re generating code from natural language or integrating it into existing projects, Codex can save time and make coding easier.