OpenAI Codex
OpenAI's coding agent, included with ChatGPT plans.
Best valueFree plan
- Best for
- ChatGPT users who code
- On your PC
- No, online only
- Works on
- Web, Mac, Windows, Linux
- Made by
- OpenAI
What’s good
- Comes with ChatGPT Plus, no extra subscription
- Runs tasks in the cloud while you do other things
- Command-line version is open source
Downsides
- Plus: about 15 to 160 messages per 5 hours on GPT-6.1 Sol
- Weekly limits may apply on top, numbers not published
- Slightly behind Claude Code on Terminal-Bench 4.0
At a glance.
- Best for
- ChatGPT users who code
- Price
- Free plan, then $20/mo
- For developers
- GPT-6.1 Sol: $2 in, $10 out per million tokens
- Version
- GPT-6.1 SolReleased 2026-09-29
- Works on
- Web, Mac, Windows, Linux, iPhone, Browser extension
- Open source
- No
- Made by
- OpenAI
- Website
- openai.com
How it ranks.
- Terminal-Bench 4.0 (Codex + GPT-6.1 Sol)#3 · 58.2%2026-11-05
Can I run it myself?
No. It only runs online.
Your prompts and files go to the company’s servers. See the local options in this category for a private alternative.
Want it offline? The best local option for coding agents is OpenCode.