AI Coding AssistantsIntermediate

Install OpenAI Codex CLI

Run OpenAI's Codex CLI from your terminal to automate coding tasks, write scripts, and modify files with AI.

5 min4 steps19 viewsUpdated Aug 5, 2026

Your Progress0%

0 of 4 steps complete

codexopenaicliterminalagentcodex cliOpenai codex cliOpeni clicontinue devinstall codex clinpm install codexcodex cli downloadvs code continuedownload codex cli

What is Codex CLI?

Codex CLI is OpenAI's open-source terminal agent that takes natural language instructions and executes real coding tasks — reading files, writing code, running commands, and fixing bugs.

Requirements

Node.js 22+
An OpenAI API key (or a compatible free API key from OpenRouter)

Install Node.js 22+

1 screenshot

Codex CLI requires Node.js version 22 or higher.

go to google and search node js download and install it

Check your current version in your terminal :

node --version

If it's below 22, download Node.js 22 LTS from nodejs.org or use a version manager:

# Using nvm (Mac/Linux)
nvm install 22
nvm use 22

📌 Important

Codex CLI requires Node.js 22 or higher. Older versions will not work.

Screenshots

Install Codex CLI

1 screenshot

npm install -g @openai/codex

Verify it installed correctly:

codex --version

💡 Tip

On Mac or Linux, you may need 'sudo npm install -g @openai/codex' if you get a permissions error.

Screenshots

Get a Free API Key via OpenRouter

1 screenshot

You can use Codex CLI for free by pointing it at OpenRouter instead of OpenAI directly.

Go to openrouter.ai and sign up for free
Click Keys → Create Key
Copy your key

Set your environment variables:

export OPENAI_API_KEY=sk-or-v1-your-key-here
export OPENAI_BASE_URL=https://openrouter.ai/api/v1
export CODEX_MODEL=meta-llama/llama-3.1-8b-instruct:free

if your credits are over on openrouter check my guide on how to use codex for free using freemodel https://growths.dev/guides/how-to-use-codex-for-free

✓ Success

Using OpenRouter's free tier means you can run Codex CLI without any OpenAI account or payment.

Screenshots

Run Your First Task

Navigate to a project and give Codex a task:

cd my-project
codex "Add input validation to all form fields in index.html"

Codex will:

Read your files
Plan the changes
Ask for your approval
Make the edits

Other example prompts:

codex "Write a Python script to rename all files in a folder"
codex "Find and fix all console.error calls in this project"
codex "Add JSDoc comments to all functions in utils.js"

⚠ Warning

Always review Codex's proposed changes before approving. In 'auto' mode it can modify files without asking.

Install OpenAI Codex CLI

What is Codex CLI?

Requirements

Install Node.js 22+

Install Codex CLI

Get a Free API Key via OpenRouter

Run Your First Task

Related AI setup guides

Install Claude Code Using OpenRouter (Free)

Run DeepSeek Coder Locally with Ollama

9 Git Commands Every Developer Should Know

6 AI Agent Trends Shaping 2026

Community Feedback

Did this guide work for you?