--- title: Enabling alternative distribution app installation in a browser framework: marketplacekit role: article role_heading: Article path: marketplacekit/enabling-alternative-distribution-app-installation-in-a-browser --- # Enabling alternative distribution app installation in a browser Add support for browser apps to install alternative distribution apps from websites. ## Overview Overview To enable the installation of an alternative distribution app from a webpage, your browser listens for installation requests from the website visitor’s interaction with the page and hands off the request to MarketplaceKit. The installation request uses a specific URL scheme (MarketplaceKitURIScheme) that the marketplace page assigns to a button. MarketplaceKit handles the request by presenting the app install sheet, in which the person can confirm and install the alternative distribution app on their device. MarketplaceKit requires a one-to-one mapping between an alternative distribution app and the domain of the website that distributes it. When a page visitor taps a button to install the app, your browser app passes the origin of the site’s main frame to MarketplaceKit, which confirms that the owner of the domain also owns the app. note: The system requires that your browser app have a specific entitlement to call the MarketplaceKit installation method. For more information and to request the entitlement, see com.apple.developer.browser.app-installation. Respond to app installation requests using BrowserEngineKit Browsers that render using BrowserEngineKit hand off app installation requests to MarketplaceKit. Your browser listens for invocations to a URL with the scheme MarketplaceKit/MarketplaceKitURIScheme: marketplace-kit://install ?alternativeDistributionPackage= &installVerificationToken= &token= &account= &appShareURL=; The URL parameters are: | | | | | | For more information about the parameters, see MarketplaceKitURIScheme. To forward the navigation request to MarketplaceKit, call the requestAppInstallationFromBrowser(for:referrer:) method to display the app install sheet and pass in the following parameters: | | | important: To comply with operation system requirements, ignore the marketplace-kit:// URL invocation if the navigation doesn’t result from a user interaction, such as tapping a button, or if the navigation results from a redirect. Respond to app installation requests using WebKit If your browser app uses WebKit, modify your app’s webView(_:decidePolicyFor:decisionHandler:) navigation delegate method. When the system calls the delegate method with a URL matching the MarketplaceKitURIScheme scheme, call the decisionHandler with a value of WKNavigationActionPolicyAllow. Don’t call the requestAppInstallationFromBrowser(for:referrer:) method directly. WebKit handles the interaction with MarketplaceKit after you call the navigation delegate’s decisionHandler with a value of WKNavigationActionPolicyAllow. Safari is an example of a browser app that uses WebKit. When a person taps on an MarketplaceKitURIScheme URL, it calls Safari’s webView(_:decidePolicyFor:decisionHandler:) navigation delegate method with a URL matching the MarketplaceKitURIScheme. Safari responds by calling decisionHandler with WKNavigationActionPolicyAllow, which then causes WebKit to pass the URL to MarketplaceKit and display an install sheet. Test web distribution during development In iOS 18.2 and later, development builds of browser apps with the default browser entitlement (com.apple.developer.web-browser) can test the installation of web-distributed marketplace apps. A development build signed with a development or Ad Hoc provisioning profile can run on Simulator and all physical devices that the target region supports. For region-based caveats, see Participating in alternative distribution for specific regions.