Why these tools exist
Converting a website into an Android app is mostly a series of small, fiddly requirements: an icon at six sizes, a package name that Gradle will accept, a version code that increases on every upload, a splash screen that respects Android 12's rules, permissions that match what your pages actually call. None of them is hard. All of them fail a build or a Play submission when they are wrong, usually after you have waited for the build to finish.
Every tool here does one of those jobs in the browser. Nothing is uploaded to a server — images are resized with the Canvas API, ZIPs are packed locally, and the encoders never see the network. That means they work offline once loaded, and that pasting a config file or an API response into one of them does not send it anywhere.
If you want the whole job done instead of the pieces, the builder takes an HTML file or a ZIP of your site and returns a signed Android app — it generates the icon set, the splash screen and the manifest for you.