OpenAI Codex Review: Features, Pricing & Alternatives

OpenAI's coding agent for desktop, terminal, IDE and cloud, included with ChatGPT plans.

FreemiumCodingReviewed October 2026

What is OpenAI Codex?

OpenAI Codex is OpenAI’s software engineering agent. It is available in the Codex desktop app, in an open-source command-line tool, as an IDE extension, on the web as cloud tasks and in the ChatGPT iOS app. Codex can read your codebase, write and run code, fix bugs, run tests and review pull requests, either on your own machine or in a cloud sandbox.

The current Codex launched as an open-source CLI in April 2025 and a cloud agent in ChatGPT in May 2025, reusing a name OpenAI first gave to a code model in 2021. In 2026 OpenAI released the Codex app for Mac in February and for Windows on 4 March, with what it called the first Windows-native agent sandbox. In April 2026 it cut ChatGPT Business to $20 per seat on annual billing.

Codex’s biggest advantage is that it comes with ChatGPT plans many people already pay for, and one sign-in works across every surface. It can run several agents in parallel, use computer and browser tools, and connect to services such as GitHub, Slack, Figma and Notion through plugins. Developers who prefer metered billing can use it with an API key instead.

Key features of OpenAI Codex

Codex appA desktop app for macOS and Windows that runs several agents in parallel, manages long tasks and shows diffs in one place.
Codex CLIAn open-source (Apache-2.0) terminal agent you can install with npm or Homebrew and run locally.
IDE extensionBrings Codex into your code editor so you can chat, edit and delegate without switching windows.
Cloud tasksSend tasks to a cloud sandbox from the web and pick up the results later on any device.
GitHub code reviewAutomatic pull request reviews that flag bugs and issues before you merge.
Plugins and integrationsConnect tools such as GitHub, Slack, Figma, Notion and Supabase, and use computer and browser tools.

Who is OpenAI Codex best for?

ChatGPT Plus and Pro subscribers who get Codex included without another subscription.
Terminal-first developers who want an open-source CLI agent they can inspect and script.
Teams on ChatGPT Business or Enterprise that need SSO, admin controls and no training on business data by default.

Popular ways to use OpenAI Codex

Feature work: ask Codex in the app or CLI to implement a feature and run the tests.
Parallel tasks: start several cloud tasks at once and review each result as it finishes.
Pull request review: turn on code review so Codex comments on new pull requests.
Bug hunting: paste an error or failing test and let Codex trace and fix the cause.
Scripting: run the CLI with an API key inside scripts or CI jobs.

OpenAI Codex pricing (October 2026)

Plan	Price	What you get
Free	$0	Limited Codex use in the desktop app (subject to rollout)
Go	$8/month	Lightweight coding tasks in the desktop app
Plus	$20/month	Codex on web, CLI, IDE and iOS, cloud integrations, option to buy credits
Pro	From $100/month ($100, $200 or $500 tiers)	Much higher limits and faster model options
Business	$20 per user/month annual, $25 monthly	Team workspace, SSO, MFA, no training on business data by default
Enterprise and Edu	Custom pricing	SCIM, audit logs, data residency and retention controls

Usage limits are measured in five-hour windows, vary by model, and cloud tasks use more than local work; Plus and Business users can buy extra credits. With an API key you pay standard API rates but lose cloud features.

OpenAI Codex pros and cons

Pros

Included with ChatGPT plans
Available on desktop, terminal, IDE, web and mobile
Open-source CLI
Native Windows sandbox

Cons

Usage limits can be hard to predict
Best features need Plus or higher
Models and plan details change often

How to get started with OpenAI Codex

Sign in to ChatGPT, or create an account, and choose a plan.
Install the Codex app, or the CLI with npm install -g @openai/codex.
Sign in with your ChatGPT account when prompted.
Review the diff and run your tests before merging.

Tips to get better results from OpenAI Codex

Add an AGENTS.md file so Codex follows your project’s commands and conventions.
Use cloud tasks for long jobs and local sessions for quick edits to save usage.
Turn on GitHub code review to catch issues before human review.

OpenAI Codex vs alternatives

Claude Code from Claude is the most direct rival as a terminal agent included in a chat subscription, and Jules by Google plays the same role for Google AI subscribers. GitHub Copilot is the default choice for many GitHub-centred teams.

If you want an AI editor rather than an agent, try Cursor or Devin Desktop; for delegated tickets with team integrations, compare Devin. See all best AI coding tools.

Our verdict: is OpenAI Codex worth it?

OpenAI Codex is a strong, flexible coding agent and great value if you already pay for ChatGPT. Plus is the sensible starting point; heavy users should compare Pro limits against Claude Code and other agents before committing.

OpenAI Codex FAQs

Is OpenAI Codex free?

ChatGPT Free and Go include limited Codex use in the desktop app. Fuller access starts with Plus at $20 per month.

Is the Codex CLI open source?

Yes. The Codex CLI is open source under the Apache-2.0 licence.

Does Codex work on Windows?

Yes. The Codex app launched on Windows on 4 March 2026 with a native sandbox, and the CLI also runs on Windows.

Can I use Codex with an API key?

Yes. You can use the CLI, SDK and IDE extension with an API key at API rates, but cloud features are not included.

Pricing and features change often. Details on this page were last reviewed in October 2026. Always confirm current plans on the official OpenAI Codex website.