Codex CLI officially supports macOS and Linux operating systems, with Windows support available but currently experimental and may require Windows Subsystem for Linux (WSL) for optimal functionality. The tool is designed to be lightweight and doesn’t have particularly demanding hardware requirements, though you’ll need sufficient disk space for the binary and any dependencies your projects might require. The CLI itself is built using Rust, which contributes to its performance efficiency and relatively small footprint on your system.
A stable internet connection is essential for Codex CLI to function properly, as the tool needs to make API calls to OpenAI’s servers to access the reasoning models like o3 and o4-mini. While the tool runs locally and processes your code on your machine, the actual AI inference happens on OpenAI’s infrastructure, requiring consistent connectivity for optimal performance. The bandwidth requirements are generally modest since the tool primarily sends prompts and receives code responses, but any network interruptions could affect the user experience.
Beyond the basic system compatibility, you’ll need a valid OpenAI account with API access to use Codex CLI effectively. The tool integrates with ChatGPT Plus, Pro, Enterprise, and Team accounts, with different usage limits and features available depending on your subscription tier. You should also ensure that your terminal environment supports the necessary permissions for Codex CLI to read, write, and execute files in your project directories. For developers working with specific programming languages or frameworks, having the relevant compilers, interpreters, or runtime environments installed will enable Codex CLI to test and validate the code it generates, though this isn’t strictly required for basic code generation functionality.