This document is a registry of supplementary members for the [[[appmanifest]]] specification that provide additional metadata to an application manifest. This metadata can be used in a digital storefront or other surfaces where this web application may be marketed or distributed, or to enhance an installation dialog when [=installed web application|installing=] a web application.

This is document is constantly evolving and we publish new snapshots every time we commit a change. Interested parties can subscribe to changes or even propose new manifest members in the manifest-app-info GitHub repository.

Marketable web applications

As web applications become available via more services (e.g., digital storefronts, search results) where they are presented alongside native applications, it becomes quite important for them to appear similarly to their native counterparts. A web application can define both its {{WebAppManifest/name}} and {{WebAppManifest/icons}} in the manifest, but those keys do not provide enough information to help users determine whether they might want to install it. Users have become accustomed to being offered more details about the applications they consider installing, and this document defines additional manifest members that can provide that.

Supplementary manifest members

The following members supplement the members of an [=application manifest=]. These members are classified as supplementary because they are not [=applied=] to a web application at runtime (i.e., they are purely advisory and don't affect how a user agent presents an installed web application). All members are all optional and can be added at the root of an [=application manifest=], as shown in the following example.

      {
        "name": "Donate App",
        "categories": ["fundraising", "donations"],
        "description": "This app helps you donate to worthy causes.",
        "iarc_rating_id": "e84b072d-71b3-4d3e-86ae-31a8ce4e53b7",
        "screenshots": [{
          "src": "images/screenshot.png",
          "sizes": "800x600",
          "platform": "windows",
          "label": "Lots of organizations to donate to",
        }]
      }
      

As the [=application manifest=] is JSON, the members of this specification are of the types object, array, and string as defined in [[[ECMA-404]]].

`categories` member

The categories member is an array of strings that describes the application categories to which the web application belongs. It is meant as a hint to catalogs or stores listing web applications and it is expected that these will make a best effort to find appropriate categories (or category) under which to list the web application. Like search engines and meta keywords, catalogs and stores are not required to honor this hint.

Manifest authors are encouraged to use lower-case.

List of known categories:

If you'd like to add additional categories, please file a bug or send a pull request to the manifest-app-info GitHub repository.

`description` member

The description member is a string that allows the developer to describe the purpose of the web application. It serves as the accessible description of an [=installed web application=].

`iarc_rating_id` member

The iarc_rating_id member is a string that represents the International Age Rating Coalition (IARC) certification code of the web application. It is intended to be used to determine which ages the web application is appropriate for.

An IARC certificate can be obtained via participating storefronts, intended to be used for distributing the web app. The iarc_rating_id member only takes a single certification code. The same code can be shared across participating storefronts, as long as the distributed product remains the same (i.e., doesn’t serve totally different code paths depending on user agent sniffing and the like) and the other storefronts support it.

More information on the IARC can be found at: How IARC Works and How developers can get their games and apps rated with IARC.

`screenshots` member

The screenshots member is an array of screenshots objects, representing the web application in common usage scenarios.

Screenshot object and its members

A screenshots object is a {{ImageResource}} object with some additional members as defined below.

`label` member

The label member is a string that serves as the accessible name of that screenshots object. For accessibility, authors are encouraged to provide a label for each screenshot.

`platform` member

The platform member is a string that represents the distribution platform for which a given screenshot applies. Authors are encouraged to only use this member when the screenshot is only applicable in a specific context.

List of general-purporse `platform` values:

narrow
For narrow screenshots (e.g., wearables, mobile devices).
wide
For screenshots applicable to wide screens only (e.g., status boards).

List of `platform` values that are specific to an operating system:

chromeos
For Google ChromeOS.
ios
For Apple iPadOS.
ios
For Apple iOS.
kaios
For KaiOS.
macos
For Apple macOS.
windows
For Microsoft Windows.
windows10x
For Microsoft Windows 10X.
xbox
For Microsoft Xbox.

List of `platform` values aligned with application distribution platforms:

chrome_web_store
Google Chrome Web Store
play
Google Play Store
itunes
iTunes App Store
microsoft
Microsoft Store

If you'd like to add additional platform, please file a bug or send a pull request to the manifest-app-info GitHub repository.

Internationalization

It is expected that authors will localize the content of all text strings defined in this document based on the approach(es) outlined in the Manifest spec.

Acknowledgements

Rob Dolin for spearheading a lot of this work, specially the `iarc_rating_id` member, and Kenneth Rohde Christiansen for helping to vet these ideas.

We'd also like to thank the following contributors: .