Guides / Comparisons

Claude Code vs Codex: Which AI Coding Agent Should You Use?

Claude vs Codex for coding, as of November 2026: where Claude Code and OpenAI Codex run, plans, free access, setup and which kind of developer each suits.

Mythex Team · 2026-11-01 · 6 min read

Claude Code and OpenAI Codex are both coding agents: you describe a task, and they read your codebase, edit files, run commands and propose changes for you to review. Pick Codex if you already pay for ChatGPT, want to start with no extra subscription, or prefer an open-source CLI. Pick Claude Code if you want the deepest set of controls over how the agent works (hooks, skills, subagents, scheduled tasks) and you're on a paid Claude plan. On raw coding ability they trade places from release to release, so the honest answer is to run both on a real task in your repository.

People search "claude vs codex" for two different things: the models behind them, and the tools themselves. This guide is about the tools. Facts come from Anthropic's and OpenAI's own sites and docs as of November 2026.

At a glance

We don't quote prices. See Claude's pricing and Codex pricing.

What they have in common

Both are agents, not autocomplete. You give a goal, such as "add rate limiting to the login route and write tests," and the agent explores the code, plans, edits several files, runs your tests and shows you the result. Both ask before running commands that could do damage, with settings to allow more or less on their own. Both work with Git, can be pointed at a GitHub repository from the cloud, and can review pull requests. Both connect to outside tools through MCP, so they can read an issue tracker or your docs while they work.

So the choice is rarely "which can do X." It's about where you work, what you already pay for, and how much you want to shape the agent's behaviour.

Where you can use them

Claude Code runs in the terminal, in VS Code and JetBrains, in the Claude desktop app, in a browser at claude.ai/code and in the Claude mobile apps. Sessions can move between them: start a long task in the cloud, then pull it into your terminal. You can mention @Claude in Slack with a bug report and get a pull request back, or run it in GitHub Actions or GitLab CI.

Codex is available in the ChatGPT desktop app, the ChatGPT mobile app, on the web, in the Codex CLI, in the IDE extension and in Codex Cloud. On Plus and above, cloud integrations include automatic code review and Slack. With an API key you can use the CLI, SDK or IDE extension without a ChatGPT plan, minus the cloud features.

If your team lives in ChatGPT already, Codex is right there. If your team lives in the terminal and IDE, both fit equally well.

Plans and free access, as of November 2026

Claude Code is included in Claude's Pro, Max and Ultra plans, in Team and Enterprise, and with Anthropic Console accounts billed at API rates. Anthropic's pricing table marks it as not included on Free.

Codex is included in every ChatGPT plan: Free, Go, Plus, Pro, Business, Edu and Enterprise. OpenAI describes Free as a way to explore Codex on quick coding tasks and Go for lightweight tasks, both in the desktop app only. Plus and Pro add the web, CLI, IDE extension and iOS. Codex and ChatGPT's work features share one usage pool.

For someone who wants to try a coding agent without paying, Codex is the only one of the two that allows it.

Customising the agent

Claude Code has the larger toolbox here. CLAUDE.md files hold your project rules and are read at the start of every session, and Claude builds its own memory as it works. Skills package repeatable workflows (a /review-pr command for the team). Hooks run your own shell commands before or after its actions, such as formatting after every edit. Subagents split a task across several agents, and the Agent SDK lets you build your own agents on the same engine. You can schedule recurring tasks in the cloud or on your desktop.

Codex is configured through a config.toml file (per user or per project), which sets models, permissions and MCP servers, plus AGENTS.md files for instructions, which you can nest inside a repository. Its CLI being open source means you can read exactly how it works, file issues and follow changes on GitHub.

If you like to shape an agent's process precisely, Claude Code gives you more handles. If you prefer fewer moving parts and an open codebase, Codex is appealing.

Permissions and safety

Giving an agent a shell is powerful, so both tools are careful about it. By default they ask for approval before risky actions such as running commands, and you can widen or narrow what they may do without asking. Claude Code lets you set this per project in its settings, and hooks can block an action outright, for example refusing any command that touches production. Codex sets its approval and sandbox behaviour in config.toml, with project files applying only in folders you've marked as trusted.

Two habits matter more than the tool: run agents on a branch, never directly on your main branch, and keep secrets in environment variables rather than in files the agent reads. Our guides to keeping API keys safe and using Git with an AI-built app cover both.

A practical way to choose

1. Check what you already pay for. A ChatGPT Plus or Business seat already includes Codex. A Claude Pro or Team seat already includes Claude Code. That alone settles it for many people.
2. Run the same task in both. Pick something real and medium-sized: "migrate this module from callbacks to async/await and keep the tests green." Compare the plan, the diff and how often you had to step in.
3. Look at review flow. Do you want changes as local diffs in your editor, or as pull requests from a cloud session? Both do both, but each team ends up preferring one.
4. Try a recurring job. Nightly dependency checks or PR reviews show how well each fits into your workflow beyond one-off tasks.

When neither is the right tool

Coding agents assume you own the rest of the stack: the framework, the database, the hosting, the domain, the secrets. If what you want is a working app rather than a better workflow on an existing codebase, an AI app builder does those jobs for you. Our guide to AI app builders vs AI coding assistants explains the trade-off.

Mythex, our product, is one such builder. You describe the app in chat, it builds a real full-stack app with a live preview, attaches a real database and file storage, and publishes to a public URL in one click, with a code editor and terminal there if you want them. It also connects to Codex, Cursor, ChatGPT and Claude as a connector, so you can create and publish Mythex projects from the agent you already use; connecting works on any plan, and the sandbox tools need Pro. Free has 5 credits a day with no card, and Pro is $25 a month with code editing, export and GitHub. See Mythex vs Cursor for how a builder compares to an editor-based agent.

For more coding-agent comparisons, read Cursor vs Windsurf vs Claude Code, Lovable vs Claude Code and GitHub Copilot alternatives. Whatever you pick, review AI-generated code before you merge it.