Codex by OpenAI — Independent Software Review

AI-powered code generation and understanding.

Compliance Transparency Index

Grade: A — Score: 90/100

Best For

• Developers who want one coding agent across ChatGPT, supported IDEs, the terminal, and cloud tasks. Work can move between these surfaces through the same ChatGPT account.
• Engineering teams delegating refactors, migrations, testing, and code review. Built-in worktrees and cloud environments support parallel tasks without sharing one working directory.
• Teams with documented engineering standards. AGENTS.md, Skills, permissions, plugins, hooks, and MCP connections can encode project rules and reusable workflows.
• Organizations already using ChatGPT Business or Enterprise. Managed workspaces add SAML SSO, RBAC on Enterprise, compliance monitoring, and business-data training protections.

Not Ideal For

• Heavy users who require a fixed number of tasks for a fixed monthly fee. Consumption varies with the model, task complexity, codebase size, context, tools, and execution location, and Codex shares its usage pool with other agentic ChatGPT features.
• Teams that need GitHub code review or Slack delegation while authenticating only with an API key. OpenAI limits API-key access to the CLI, SDK, and IDE extension and excludes those cloud features.
• Small teams that require SCIM, EKM, RBAC, audit logs, configurable retention, or data residency on a self-service plan. OpenAI documents those controls under custom-priced Enterprise and Edu plans rather than the $20 annual Business tier.
• Individual users unwilling to review ChatGPT data controls. Plus and Pro Codex conversations may be used to improve OpenAI models unless the account holder turns off training.

Operational Overview

Pricing Structure

Free: $0/month

• Codex access for quick coding tasks
• Shared plan usage limits

Go: $8/month

• Codex access for lightweight coding tasks
• Shared plan usage limits

Plus: $20/month

• Web, CLI, IDE extension, and iOS access
• Cloud code review and Slack integration
• Optional ChatGPT credits after included usage

Pro (5x): $100/month

• Everything in Plus
• Five times the Codex usage allowance of Plus
• Access to the Codex Spark research preview

Pro (20x): $200/month

• Everything in Plus
• Twenty times the Codex usage allowance of Plus
• Unlimited ChatGPT Voice, with Codex tasks still metered separately

Business: $20/user/month billed annually, or $25/user/month monthly; 2-user minimum

• Dedicated workspace with SAML SSO and MFA
• Larger virtual machines for cloud tasks
• No training on business data by default

Enterprise & Edu: Custom pricing

• SCIM, EKM, domain verification, and role-based access control
• Compliance API audit logs and usage monitoring
• Data retention and data residency controls

Alternative Consideration

Consider switching to GitHub Copilot: GitHub Copilot offers similar code generation capabilities with integration into popular IDEs.

Frequently Asked Questions

How do Codex usage limits work?

Codex does not provide a fixed number of tasks for each subscription. Usage varies with the selected model, task complexity, codebase size, context, tools, and whether work runs locally or in the cloud, and it shares an agentic usage pool with other eligible ChatGPT features. You can review remaining usage in the dashboard or with /status in the CLI, then add credits where supported, upgrade, or wait for the limit to reset.

Can Codex run in VS Code, Cursor, Windsurf, Xcode, or JetBrains IDEs?

Yes. Codex provides an extension for Visual Studio Code and compatible editors including Cursor and Windsurf, while Xcode and JetBrains IDEs provide separate Codex integrations. The editor workflow can attach open files, selected code, and recent chats as context and shows the resulting changes for review.

Can Codex work on a local repository without running every task in the cloud?

Yes. Codex CLI and local editor workflows can inspect files, edit code, and run tools installed on your device, while delegated cloud tasks run in OpenAI-managed environments. You choose the execution surface and permissions, then review the diff and command evidence before accepting the changes.

Does OpenAI use Codex code and conversations to train its models?

For individual plans, Codex content may be used to improve OpenAI models unless the user turns off training in ChatGPT data controls and reviews the separate controls for full-environment Codex data. OpenAI states that Business, Enterprise, Edu, and API inputs and outputs are not used for training by default. This is why the finalized Codex record classifies training opt-out as available rather than claiming universal no-training treatment.

Can Codex review GitHub pull requests automatically?

Yes, when Codex cloud is configured for the repository and the plan includes cloud code review. You can request a review with @codex review or enable automatic reviews, and Codex posts a standard GitHub review focused on high-priority issues. Repository-specific review guidance can be added through AGENTS.md, but Codex review does not replace tests, branch protections, or required human approvals.

Can Codex follow repository-specific instructions with AGENTS.md?

Yes. The /init command can create an AGENTS.md scaffold, and Codex reads applicable instruction files to follow project conventions and review rules. Root instructions can apply across the repository, while nested AGENTS.md files can provide more specific guidance for particular services or directories.

Can Codex run multiple coding tasks in parallel?

Yes. Codex can delegate multiple tasks to isolated cloud environments and use separate Git worktrees so agents do not share one working directory. This is useful for parallel feature work, refactors, tests, or reviews, but each result still needs inspection before it is merged.

How does Codex compare with Claude Code?

Codex spans ChatGPT, supported IDEs, the CLI, GitHub review, Slack workflows, and OpenAI-managed cloud tasks, while Claude Code is centered on Anthropic's terminal, IDE, desktop, and browser workflow. Codex Plus and Claude Pro both start at $20 per month, while higher individual usage starts at $100 per month through Codex Pro or Claude Max. The better fit depends on whether you value Codex's ChatGPT and cloud-task ecosystem or prefer Anthropic's coding workflow and models.

How does Codex compare with Cursor?

Codex is a coding agent that works across ChatGPT, supported editors, the CLI, and cloud environments, while Cursor makes its VS Code-based editor the center of the workflow. Codex Plus and Cursor Pro both cost $20 per month, and Cursor Teams costs $40 per user per month with SAML or OIDC SSO and team privacy mode. Choose Cursor for an AI-first editor experience or Codex when you want the same agent across multiple surfaces and delegated cloud tasks.

How does Codex compare with GitHub Copilot?

GitHub Copilot is the lower-cost GitHub-native option, with a Free plan that includes 2,000 code completions per month and Copilot Pro at $10 per month. Codex Plus costs $20 per month and emphasizes end-to-end agent work across ChatGPT, IDEs, the CLI, cloud tasks, Slack, and GitHub code review. Copilot is the stronger fit for developers prioritizing GitHub integration and autocomplete economics, while Codex is broader for delegated multi-step engineering work.

AI Visibility Report

How AI agents (ChatGPT, Perplexity, Claude, others) read this review page in the past 7 days. Updated weekly. View Codex by OpenAI AI Visibility Report.