gpt-4 · gpt-4o

Codex CLI Relay Setup Guide

OpenAI's official AI programming CLI — use it without an OpenAI account. Configure OPENAI_BASE_URL with a relay for China-direct access.

What is Codex CLIInstallationRelay ConfigurationVerificationFAQ

// What is Codex CLI

What is Codex CLI?

Codex CLI is OpenAI's official command-line coding tool, built on GPT-4o and GPT-5 models. Similar to Claude Code, it provides conversational code editing. Unlike Claude Code, it uses OpenAI's model family.

// Key advantage: No OpenAI account needed — use it directly through a relay.

Codex CLI vs Claude Code

Both are CLI coding assistants with similar positioning. Core difference: Codex uses OpenAI GPT series, Claude Code uses Anthropic Claude series. They each have advantages on different tasks — choose based on your actual experience.

Feature	Codex CLI	Claude Code
Underlying Model	GPT-4o / GPT-5	Claude Sonnet / Opus 4
Developer	OpenAI	Anthropic
Model Style	Strong at code completion, simple tasks	Strong at architecture design, complex reasoning
Context Window	200K	200K
Relay Support	Most platforms supported	Most platforms supported

// Recommended

Recommended Platforms

These platforms have strong Codex CLI support

⚡

CodeCMD — Four-Tool Support

Claude Code + Codex + OpenCode + ClawdBot universal, $200 Max account pool dynamic scheduling.

⚡

SSSAiCode — Lowest Multiplier

0.45x multiplier, credits never expire. Claude Code + Codex + Gemini CLI all supported.

🚀

AICoding — Plug and Play

Claude Code + Codex dual support, one-click install, zero config.

// Installation

Install Codex CLI

Official CLI tool, cross-platform support

macOS / Linux

Install via npx or npm

# Install globally via npm
npm install -g @openai/codex

# Or run directly with npx (no install needed)
npx @openai/codex

Windows

Install via npm

# Install globally via npm
npm install -g @openai/codex

// Codex CLI officially requires an OpenAI API Key, which must be purchased from OpenAI (requires an overseas credit card). With a relay, you only need the relay-provided Key and endpoint URL to bypass this restriction.

// Configure Relay

Configure Your Relay

Set environment variables to replace official endpoints

Get Relay API Key

Register on your chosen relay platform and get your API key. Note: Codex CLI uses an interface format compatible with standard OpenAI API.

Set Environment Variables

Configure OPENAI_API_KEY and OPENAI_BASE_URL environment variables.

# Bash / Zsh / Linux
# Temporary (current session)
export OPENAI_API_KEY="your-relay-api-key"
export OPENAI_BASE_URL="https://your-relay.com/v1"

# Permanent (add to config file)
echo 'export OPENAI_API_KEY="your-relay-api-key"' >> ~/.bashrc
echo 'export OPENAI_BASE_URL="https://your-relay.com/v1"' >> ~/.bashrc
source ~/.bashrc

Launch Codex

Run codex, enter your API key when prompted.

// Verification

Verification

Confirm your setup and start using Codex CLI

Launch Codex CLI

Run the codex command. On first launch it will prompt for your API Key.

# Run directly
codex

# Or verify version
codex --version

Common Parameters

Codex CLI supports various parameters for specifying models and run modes.

# Specify model
codex --model gpt-4o

# Specify working directory
codex --directory ./my-project

# Preview mode (no execution)
codex --no-execute

// FAQ

FAQ

Q1.Does Codex CLI need an OpenAI account?

Technically yes, but through a relay you can completely bypass this. The relay provides its own API key for using Codex CLI — no OpenAI account needed. This is the biggest value for China mainland developers.

Q2.What's the difference between Codex CLI and GitHub Copilot?

Codex CLI is a pure command-line tool interacting through conversation. GitHub Copilot is an IDE plugin focused on real-time code completion. Codex CLI is more flexible for complex multi-step tasks; Copilot is better for quick completions in daily coding.

Q3.GPT-4o or GPT-5 Codex — which is better?

GPT-5 Codex is OpenAI's latest and most capable model but also most expensive. GPT-4o is the value choice — more than enough for most coding tasks. Test with GPT-4o first, upgrade to GPT-5 based on your needs.

Q4.Does Codex CLI support Windows?

Yes — Codex CLI is Node.js-based and cross-platform compatible. But some relays have limited Windows support. Choose platforms explicitly marked as Windows-compatible.

Q5.Are there usage limits on Codex CLI?

When using via relay, limits depend on the platform's policy. Budget platforms usually have stricter rate limits; premium platforms are more relaxed. Check the platform's limit documentation before purchasing to avoid hitting walls at critical moments.

Browse All Platforms

View Platform List