# ChatGPT and Codex guides

ChatGPT and Codex are now one app. Install the ChatGPT desktop app, and you can switch between ChatGPT (for chatting and writing) and Codex (for coding) from the dropdown menu in the top-left corner. That's why the guides below cover both together, with one page each for downloading, signing in and using it.

## Where to start

<TileGrid>
  <LinkTile title="I topped up ChatGPT Plus / Pro" href="/en/guides/plans/" icon="star">
    First check that the plan is active. Then download the app and sign in with the account you topped up.
  </LinkTile>
  <LinkTile title="I bought balance or a plan on 2api" href="/en/guides/install/" icon="rocket">
    Install Codex first, then set up 2api in one click with magpie. No config files to edit.
  </LinkTile>
</TileGrid>

## Two ways to pay

| | With a ChatGPT subscription | With a 2api key |
| --- | --- | --- |
| Who it's for | You topped up Plus or Pro at [cz.2api.dev](https://cz.2api.dev) | You have balance or a plan on 2api |
| Billing | Uses the usage included in your plan. When it runs out, you wait for it to reset (Plus has a 5-hour limit) | Charged for what you use, from your 2api balance. For prices, see the [group multipliers](https://docs.2api.dev/en/start/endpoints/#groups) |
| Sign-in | **Sign in with ChatGPT**, using the account you topped up | Sign in with an API key. We recommend [one-click setup with magpie](https://docs.2api.dev/en/magpie/) |
| Features | Everything in ChatGPT and Codex, including cloud tasks and the mobile app | Codex for coding on your computer. ChatGPT chat and cloud tasks need a ChatGPT account |

To use both, let magpie handle it: Codex stays signed in with ChatGPT, and 2api's models show up in Codex's model menu. Pick a model and that's the side you use. No config files to edit.

<MagpieLink lang="en" href="/en/magpie/#use-it-with-a-chatgpt-subscription" title="Use 2api and your ChatGPT subscription together with magpie">Using both? Start here</MagpieLink>

If you use a ChatGPT subscription, note this: Free and Go can only use Codex in the desktop app. Plus and Pro can also use it in the IDE extension, the CLI, on the web and on iOS.

## All pages

- [Download and install](https://docs.2api.dev/en/guides/install/): the desktop app, the web version, the mobile apps, the IDE extension and the CLI
- [Sign in](https://docs.2api.dev/en/guides/login/): with a ChatGPT account, or with a 2api API key
- [Plus and Pro](https://docs.2api.dev/en/guides/plans/): checking that a top-up is active, and how usage is counted
- [Using ChatGPT and Codex](https://docs.2api.dev/en/guides/usage/): common ChatGPT features, and your first coding task with Codex
- Having problems: [ChatGPT and Codex FAQ](https://docs.2api.dev/en/faq/chatgpt/), [Using Codex on Windows](https://docs.2api.dev/en/faq/codex-windows/)

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This section follows OpenAI's official documentation, checked in October 2026. OpenAI updates often, so button names and menu locations may differ slightly. Go by what you see on screen.