index.md

---

title: incognito
slug: Mozilla/Add-ons/WebExtensions/manifest.json/incognito
page-type: webextension-manifest-key
tags:
  - Add-ons
  - WebExtensions
  - incognito
  - manifest.json
browser-compat: webextensions.manifest.incognito

---

{{AddonSidebar}}

Type	String
Mandatory	No
Manifest version	2 or higher
Example	"incognito": "spanning" "incognito": "split" "incognito": "not_allowed"

Use the incognito key to control how the extension works with private browsing windows.

Note: By default, extensions do not run in private browsing windows. Whether an extension can access private browsing windows is under user control. For details, see Extensions in Private Browsing. Your extension can check whether it can access private browsing windows using {{WebExtAPIRef("extension.isAllowedIncognitoAccess")}}.

This is a string that can take any of these values:

• "spanning" (the default): the extension will see events from private and non-private windows and tabs. Windows and tabs will get an incognito property in the Window or Tab that represents them. This property indicates whether or not the object is private:

  browser.windows.getLastFocused().then((windowInfo) => {
    console.log(`Window is private: ${windowInfo.incognito}`);
  });
  

• "split": the extension will be split between private and non-private windows. There are effectively two copies of the extension running: one sees only non-private windows, the other sees only private windows. Each copy has isolated access to Web APIs (so, for example, localStorage is not shared). However, the WebExtension API storage.local is shared. (Note: this setting is not supported by Firefox.)

• "not_allowed": private tabs and windows are invisible to the extension.

Example

"incognito": "spanning"

"incognito": "split"

"incognito": "not_allowed"

Browser compatibility

{{Compat}}