Web app generator: manifest and icons
Turn your site into an app people can install on phones and computers: manifest, icons (including Android's maskable and the iPhone one) and the <head> lines, in a .zip.
What is an installable web app?
It is your site looking like an app: it gets an icon on the home screen, opens full screen without the browser bar and shows up in the phone's and computer's app list. No store and no new code: a configuration file (the manifest), the icons and a few lines in the pages' <head> are enough. The site must use HTTPS.
The manifest
manifest.webmanifest is a JSON file that tells the browser the app name, the short name (what fits under the icon), the start page, the colors of the bar and of the splash screen, and where the icons are. It lives at the site root and is linked by one line in the <head>.
The icons (and the maskable one)
Chrome asks for 192 and 512 pixel icons. Android crops the icon into the phone's shape (circle, teardrop, rounded square): the "maskable" icon has background up to the edge and the drawing inside the central 80% circle, so nothing gets cut. The iPhone uses another one, the apple-touch-icon, and does not accept transparency.
Android, iPhone and desktop: what changes
On Android and desktop (Chrome and Edge), the app is installed from the browser menu ("Install app" or "Add to home screen"). The automatic install invitation only shows up if the site has a service worker, the small program that works offline; without it, installing from the menu still works. On the iPhone there is no invitation: people tap Share and "Add to Home Screen", and the icon comes from the apple-touch-icon.
How it will look
Things to check
manifest.webmanifestLines for the <head>By using the tools, you agree to the terms of use.