OpenAI Codex — Best API Configuration Guide

OpenAI Codex CLI installation and configuration notes.

Requirements

• macOS 12+, Ubuntu 20.04+/Debian 10+, or Windows 11 via WSL2
• Node 22+

Install

npm i -g @openai/codex
# or on macOS via Homebrew
brew install codex

Configure

Create ~/.codex/config.toml and set provider and model, for example:

model_provider = "vapi"
model = "gpt-5.1"

[model_providers.vapi]
name = "VAPI"
base_url = "https://api.morphogen.top/v1"
env_key = "V_API_KEY"
wire_api = "responses"

Set environment variable

export V_API_KEY="sk-xxxxxx"

Usage

codex "hello"