OpenAI Codex CLI

Freemium
Featured
API Available

OpenAI's open-source terminal coding agent powered by its reasoning models

OpenAI · Code Assistance Launched Apr 16, 2025

Visit Website

Quick Answer

OpenAI Codex CLI is openai's open-source terminal coding agent powered by its reasoning models, made by OpenAI. It offers a free tier with paid upgrades. Key uses: Terminal-based coding, Multi-file refactoring, Test generation and fixing.

Last updated:

Users
Codex reached 3M weekly users (Apr 2026)
Growth
Fastest-growing OpenAI developer product

What is OpenAI Codex CLI?

Codex CLI is OpenAI's open-source command-line coding agent that runs in your terminal and edits code, runs commands, and executes tests in a sandbox on your local machine. Powered by OpenAI's codex-optimized reasoning models, it reads your repository, plans multi-step changes, and applies them with approval controls. It complements the cloud-based Codex agent, giving developers a local, scriptable, terminal-native agentic coding workflow.

What's new in OpenAI Codex CLI in 2026?

Codex CLI reached general availability alongside the Codex cloud agent (2025); usage now bundled with ChatGPT Plus, Pro, Team, and Enterprise plans; added MCP support, approval/auto modes, and image inputs; Codex crossed 3M weekly users by Apr 2026 as OpenAI's fastest-growing developer product

How much does OpenAI Codex CLI cost?

Included with ChatGPT Plus

$20/mo

  • Codex CLI + cloud agent
  • Reasoning model access
  • Standard usage limits

ChatGPT Pro

$200/mo

  • Much higher usage
  • Priority access
  • Best for heavy agentic coding

API (pay-as-you-go)

Token-based

  • Bring your own API key
  • No subscription needed
  • Full CLI features

What can you do with OpenAI Codex CLI?

  • Terminal-based coding
  • Multi-file refactoring
  • Test generation and fixing
  • Scripted automation of code tasks
  • Local agentic development

Pros

  • Open-source (Apache 2.0)
  • Runs locally in the terminal
  • Sandboxed execution with approval modes
  • Included with ChatGPT Plus/Pro/Business plans
  • Scriptable and CI-friendly

Cons

  • Terminal-first (no rich GUI)
  • Heavy usage can hit plan limits
  • Requires OpenAI account/API
  • Newer than some rivals

Specs

Underlying Models

  • codex-optimized GPT-5 family
  • o4-mini

Platforms

  • macOS
  • Linux
  • Windows (WSL)

Integrations

  • GitHub
  • MCP servers
  • Terminal tools
  • ChatGPT sign-in
  • OpenAI API

Ideal For

  • Professional developers
  • Terminal power users
  • DevOps and automation
  • OpenAI ecosystem users

Tags

What are the best alternatives to OpenAI Codex CLI?

Compare OpenAI Codex CLI Head-to-Head

4

Frequently Asked Questions about OpenAI Codex CLI

How much does OpenAI Codex CLI cost?

OpenAI Codex CLI pricing: Included with ChatGPT Plus at $20/mo; ChatGPT Pro at $200/mo; API (pay-as-you-go) at Token-based.

Is OpenAI Codex CLI free?

OpenAI Codex CLI offers a free tier with limited usage. Paid plans unlock additional features.

What is OpenAI Codex CLI used for?

OpenAI Codex CLI is used for: Terminal-based coding, Multi-file refactoring, Test generation and fixing, Scripted automation of code tasks, Local agentic development.

What are the best alternatives to OpenAI Codex CLI?

Top alternatives to OpenAI Codex CLI include Cursor, Aider, Claude Code, Gemini CLI.

What platforms does OpenAI Codex CLI support?

OpenAI Codex CLI is available on: macOS, Linux, Windows (WSL).