instantpwa
Glossary

Definition

WebAPK

Short definition

A WebAPK is a small, real Android application package that Chrome generates and signs on the fly (via a Google-run server) when a user installs a qualifying PWA on Android. It gives the installed site a genuine entry in Android Settings > Apps, its own task-switcher identity separate from Chrome, and the ability to be the registered handler for its own scope's URLs.

Reviewed August 8, 2026

Before WebAPK, "installed" PWAs on Android were essentially bookmarked shortcuts running inside Chrome; WebAPK made installed PWAs behave like any other Android app for system purposes such as uninstall flows, storage reporting and default-app associations.

WebAPK generation requires meeting Chromium's full installability criteria (valid manifest, HTTPS, registered service worker, qualifying icons) — sites that only meet partial criteria may still get a home-screen shortcut but without full WebAPK identity.

Updates to the manifest (name, icons, theme_color) can trigger Chrome to silently regenerate the WebAPK in the background on the next visit, since the underlying APK bytes are derived from manifest content rather than hand-edited by the developer.

WebAPK is Android/Chromium-specific; iOS has no equivalent packaging step, which is one reason install measurement and behavior genuinely differ between the two platforms rather than being a simple superficial UI difference.

Related terms
Related applications
related_applications is a manifest array such as [{"platform": "play", "id": "com.example.app"}] listing native app store equivalents of the PWA. The companion boolean field prefer_related_applications, when true, tells Chromium to prefer directing the user to install the native app instead of showing the web install prompt.
appinstalled event
appinstalled is a window event, listened for with window.addEventListener("appinstalled", () => { ... }), that fires after the browser has finished installing the PWA — regardless of whether the install was triggered via the native beforeinstallprompt flow or a browser menu item. It fires exactly once per successful install and carries no event detail beyond the fact that installation completed.
Maskable icons
A maskable icon is declared with "purpose": "maskable" in the manifest icons array and must fill the entire square canvas with no transparent padding, keeping important content inside the central 80% "safe zone". Android then applies its own mask shape (circle, squircle, rounded square) on top without cutting off the logo.
Standalone mode detection
Standalone mode detection means checking, at runtime, whether the current page is running as an installed app rather than a regular tab. On Chromium and most browsers this is window.matchMedia("(display-mode: standalone)").matches; on iOS Safari the historical equivalent is the non-standard navigator.standalone boolean, since iOS predates the display-mode media feature's adoption there.
Safari share sheet install
On iOS, installing a PWA requires the user to manually tap the Share icon in Safari's toolbar, then choose "Add to Home Screen" from the resulting menu — there is no beforeinstallprompt equivalent, no browser-generated install banner, and no way for a site to trigger this flow programmatically.
PWA install criteria
Chromium's PWA install criteria require: the site served over HTTPS; a linked Web App Manifest with at least a name (or short_name), a 192x192 and 512x512 icon, a start_url, and a display value of standalone, fullscreen, minimal-ui or a display_override entry; and a registered service worker with a fetch event handler, even a minimal pass-through one.