O

Codex

AI agent

by OpenAI

Coding agent that reads, edits and runs a codebase from the terminal, an IDE extension and the ChatGPT web app.

Find alternatives to Codex

Included in paid ChatGPT plans; metered API usage is billed separately.

What it does

• Agentic coding
• Code generation
• Code review

How it compares

• Claude Code

  The two labs' rival coding agents, in what the cited source calls a low-grade war between OpenAI and Anthropic over AI-coding tools; the quote names the companies, and these are the tools it is fought with.

  There is currently a low-grade war between OpenAI and Anthropic over who can release the most convenient and powerful AI-coding tools.

  News reporting · 25 Aug 2026
• Cursor

  Both AI coding tools measured in the same JetBrains 2026 workplace survey; Cursor is joint-second in adoption there, and Codex is OpenAI's entry in the same market.

  We are now ready to share how AI coding tools like Claude Code, Cursor, JetBrains AI Assistant, Junie, GitHub Copilot, OpenAI Codex, and Google Antigravity have evolved over the past two years in terms of awareness, adoption, and satisfaction.

  Research report · 25 Aug 2026
• GitHub Copilot

  Both AI coding tools in JetBrains' 2026 workplace survey — GitHub Copilot the market's former long-standing leader, Codex OpenAI's own entry chasing the same developers.

  We are now ready to share how AI coding tools like Claude Code, Cursor, JetBrains AI Assistant, Junie, GitHub Copilot, OpenAI Codex, and Google Antigravity have evolved over the past two years in terms of awareness, adoption, and satisfaction.

  Research report · 25 Aug 2026
• Muse Code

  The move attempts to position Meta more competitively, and more affordably, with AI lab peers like OpenAI and its coding agent Codex, and Anthropic with Claude Code.

  News reporting · 19 Sep 2026

Sources

Pricing

Official documentation · 2 Sep 2026

Verified 2026-09-02: URL 200, name and pricing unchanged; merge-into-desktop-app language noted as a watch item.

Sold within

Pricing page · 6 Sep 2026

The same ladder states Codex access per tier in OpenAI's own words — Free: 'Limited Codex access'; Plus: 'Expanded Codex usage'; Pro: 'Maximum Codex tasks'. It is reached by holding a ChatGPT plan, not bought separately.

Also from OpenAI

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• ChatGPT for Excel Application

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• ChatGPT for PowerPoint Application

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• OpenAI API Model API

  Hosted API for OpenAI's text, image, audio and embedding models, billed per token.

• ChatGPT Atlas Application

  OpenAI's agentic web browser. Deprecated on 9 August 2026, with its browser-based agentic capabilities moved into ChatGPT and Codex.

• ChatGPT Gov Application

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• OpenAI Daybreak Agent platform

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• OpenAI Frontier Agent platform

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• Sora Application

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