Codex

OpenAI's coding agent, and the engine under ChatGPT Work.

What it offers

Codex desktop app

“Superapp” with computer use, in-app browser, automations and 90+ plugins.

Codex CLI · IDE · cloud

Terminal agent (voice added today), editor extension and cloud tasks that return pull requests.

Codex mode in ChatGPT

On every plan since July. Usage figures vary: 5M+ weekly (OpenAI, June); 25M "active" (Codex lead, Aug).

DevDay additions

Cloud execution that continues across devices, CLI agents, and Codex Security Cloud (29 Sep).

Recent news

• 29 Sep 2026DevDay 2026 adds Codex cloud execution, CLI agents and Codex Security CloudCodex tasks can run in the cloud and continue on other devices; Codex now covers PR review and security scanning.InfoQ ↗
• 9 Jul 2026Codex merges into the new ChatGPT desktop app with GPT-5.6Codex now sits beside Chat and Work in ChatGPT, putting the coding agent in front of ChatGPT's whole user baseOpenAI Help Center ↗
• Jul 2026Codex passes 8 million weekly users days after GPT-5.6Weekly users rose from under 1M in February to 8M, the fastest growth in the categoryThe New Stack ↗
• 2 Jun 2026Codex reaches 5M weekly users, 20% of them knowledge workersCodex is expanding beyond developers into general knowledge work, against Claude CoworkConstellation Research ↗
• 15 May 2026Codex arrives in ChatGPT mobile as usage tops 4M weeklyDevelopers can now steer and approve agent work from their phoneseWeek ↗