OpenAI Codex

By OpenAI · chatgpt.com/codex ↗

OpenAI's coding agent, with more than 2 million weekly users by March 2026.

Codex began as an open-source command-line agent in April 2025. In March 2026 OpenAI added Codex Security, an agent that finds and fixes software vulnerabilities.

What it can do

• Writing code and fixing bugs
• Running commands and editing files
• Codex Security: finding and fixing vulnerabilities

How to start

1. Use Codex in ChatGPT on the web, install the Codex CLI, or the desktop app for Windows and macOS
2. Sign in with your ChatGPT account

Things to know

• OpenAI may train on Codex interactions unless you opt out

Sources

• Wikipedia: OpenAI Codex
• TechCrunch

Information checked on 6 Oct 2026. Features and prices change often; the official site has the latest.