app/browser.md Codex Docs, 2026-04-23 00:46 UTC → 2026-05-02 06:45 UTC

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21![Codex app showing a browser comment on a local web app preview](/images/codex/app/in-app-browser-light.webp)21![Codex app showing a browser comment on a local web app preview](/images/codex/app/in-app-browser-light.webp)

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23## Browser use

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25Browser use lets Codex operate the in-app browser directly. Use it for local

26development servers and file-backed previews when Codex needs to click, type,

27inspect rendered state, take screenshots, or verify a fix in the page.

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29To use it, install and enable the Browser plugin. Then ask Codex to use the

30browser in your task, or reference it directly with `@Browser`. The app keeps

31browser use inside the in-app browser and lets you manage allowed and blocked

32websites from settings.

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34Example:

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36```text

37Use the browser to open http://localhost:3000/settings, reproduce the layout

38bug, and fix only the overflowing controls.

39```

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41Codex asks before using a website unless you've allowed it. Removing a site from

42the allowed list means Codex asks again before using it; removing a site from the

43blocked list means Codex can ask again instead of treating it as blocked.

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23## Preview a page45## Preview a page

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251. Start your app's development server in the [integrated terminal](https://developers.openai.com/codex/app/features#integrated-terminal) or with a [local environment action](https://developers.openai.com/codex/app/local-environments#actions).471. Start your app's development server in the [integrated terminal](https://developers.openai.com/codex/app/features#integrated-terminal) or with a [local environment action](https://developers.openai.com/codex/app/local-environments#actions).