app/browser.md Codex Docs, 2026-03-28 06:26 UTC → 2026-04-25 00:42 UTC

1# In-app browser

2 

3The in-app browser gives you and Codex a shared view of rendered web pages

4inside a thread. Use it when you're building or debugging a web app and want to

5preview pages and attach visual comments.

6 

7Use it for local development servers, file-backed previews, and public pages

8that don't require sign-in. For anything that depends on login state or browser

9extensions, use your regular browser.

10 

11Open the in-app browser from the toolbar, by clicking a URL, by navigating

12manually in the browser, or by pressing <kbd>Cmd</kbd>+<kbd>Shift</kbd>+<kbd>B</kbd>

13(<kbd>Ctrl</kbd>+<kbd>Shift</kbd>+<kbd>B</kbd> on Windows).

14 

15The in-app browser does not support authentication flows, signed-in pages,

16 your regular browser profile, cookies, extensions, or existing tabs. Use it

17 for pages Codex can open without logging in.

18 

19Treat page content as untrusted context. Don't paste secrets into browser flows.

20 

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

22 

23## Browser use

24 

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.

28 

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.

33 

34Example:

35 

36```text

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

38bug, and fix only the overflowing controls.

39```

40 

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.

44 

45## Preview a page

46 

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).

482. Open an unauthenticated local route, file-backed page, or public page by

49 clicking a URL or navigating manually in the browser.

503. Review the rendered state alongside the code diff.

514. Leave browser comments on the elements or areas that need changes.

525. Ask Codex to address the comments and keep the scope narrow.

53 

54Example feedback:

55 

56```text

57I left comments on the pricing page in the in-app browser. Address the mobile

58layout issues and keep the card structure unchanged.

59```

60 

61## Comment on the page

62 

63When a bug is visible only in the rendered page, use browser comments to give

64Codex precise feedback on the page.

65 

66- Turn on comment mode, select an element or area, and submit a comment.

67- In comment mode, hold <kbd>Shift</kbd> and click to select an area.

68- Hold <kbd>Cmd</kbd> while clicking to send a comment immediately.

69 

70After you leave comments, send a message in the thread asking Codex to address

71them. Comments are most useful when Codex needs to make a precise visual change.

72 

73Good feedback is specific:

74 

75```text

76This button overflows on mobile. Keep the label on one line if it fits,

77otherwise wrap it without changing the card height.

78```

79 

80```text

81This tooltip covers the data point under the cursor. Reposition the tooltip so

82it stays inside the chart bounds.

83```

84 

85## Keep browser tasks scoped

86 

87The in-app browser is for review and iteration. Keep each browser task small

88enough to review in one pass.

89 

90- Name the page, route, or local URL.

91- Name the visual state you care about, such as loading, empty, error, or

92 success.

93- Leave comments on the exact elements or areas that need changes.

94- Review the updated route after Codex changes the code.

95- Ask Codex to start or check the dev server before it uses the browser.

96 

97For repository changes, use the [review pane](https://developers.openai.com/codex/app/review) to inspect the

98changes and leave comments.