Codex

What it does

Codex is OpenAI's coding agent, built into ChatGPT and also available in an editor extension and a terminal CLI, all tied to one account. You hand it a task — a bug fix, a refactor, a routine pull request — and it works through a cloud sandbox: writing code, running it, testing it, and showing you the result before anything merges. Multiple Codex agents can run in parallel across different parts of a codebase, and it can be scheduled for background work like issue triage or CI monitoring.

Who this helps

Your dev team is buried in routine pull requests and code review and wants an agent to take the first pass.

You need a bug fixed or a small feature shipped fast and don't want to context-switch out of ChatGPT.

You manage an engineering team and want consistent code review standards applied automatically.

You're comfortable already working in code and want an agent that plugs into your existing editor and terminal.

Free tier:

Yes, but limited — included in ChatGPT Free at a small usage cap; realistic daily use starts around the $20/mo Plus plan.