Codex
: How to use it, features, and the business problems it solves

How to Use

1. Log in to ChatGPT

   Subscribe to a ChatGPT Pro, Team, or Enterprise plan and log in to your account.

2. Enable Codex

   Turn on the "Codex" feature in ChatGPT's settings and select the repositories or projects you want to use.

3. Enter a task

   Give instructions in natural language, such as "Fix this bug" or "Add a new feature," to assign a task to Codex.

4. Codex runs the task

   Codex executes the task in a cloud sandbox environment, generating or modifying code, running tests, and more.

5. Review the results

   Check the code, changes, and test results that Codex produced, and revise or approve them as needed.

6. Integrate the code

   Merge the reviewed code into your repository and continue your development process.

---

Features

• Code generation from natural language

  Automatically generates and modifies code based on natural-language instructions.

• Bug fixing and code review

  Analyzes your existing codebase to identify and fix bugs and suggest improvements.

• Automatic test execution

  Automatically runs tests against the generated code to ensure quality.

• Cloud sandbox environment

  Each task runs in an isolated cloud environment without affecting other processes.

• Parallel processing of multiple tasks

  Runs multiple tasks at once to improve development efficiency.

• Codebase understanding and navigation

  Understands the code structure within a repository and locates the right files and functions.

• Security and privacy protection

  Your code and data are managed securely, with privacy protected.

• Multi-language support

  Supports more than 30 programming languages, including Python, JavaScript, TypeScript, Go, Java, C++, C#, Swift, PHP, and Rust.

---

Pricing

There is no standalone Codex plan—it is bundled into your ChatGPT subscription. The higher your plan, the more Codex tasks you can run.

Individual plans

Business plans

• Prices reflect the official ChatGPT pricing page as of July 2026. Check the official site for current prices and limits.

---

Reviews and who it suits

What people rate highly

• Cloud execution keeps your machine clean: each task runs in its own sandbox, so it never touches your local environment or build configuration. Parallel tasks do not interfere with each other.
• Included in your ChatGPT subscription: there is no separate tool to buy. If you already use ChatGPT, you can try it at no extra cost, and even the free plan runs it under a quota—which makes it easy to evaluate.
• It reads the whole repository before acting: rather than completing single lines, it works out the structure of the codebase, locates the relevant files, and carries the change through to running tests.

Points to be aware of

• Per-plan limits determine how usable it is: quotas on Free and Go are tight, so Plus or above is effectively the baseline for day-to-day development. Hitting the ceiling sooner than expected is the most common stumbling block.
• You still have to review the output: test execution is automated, but confirming the change does what you intended remains human work.

Who it suits: developers who already subscribe to ChatGPT and want to hand off the "hands busy, brain idle" work—bug fixes, adding tests. If you prefer writing code conversationally inside your editor, an IDE-integrated tool will fit better.