Turn a Web Game into a Desktop and Mobile App
Short answer: Open the folder with your game's index.html in GemShell, tick the platforms you want and press build. You get a Windows .exe, a macOS .app and a Linux launcher, plus ready Xcode and Android Studio projects for iOS and Android — all from the computer you are sitting at. Your game code stays exactly as it is.
What each platform gets
| Platform | What GemShell builds | Architectures |
|---|---|---|
| Windows | a folder with YourGame.exe | x64, ARM64, 32-bit |
| macOS | YourGame.app, signed if you give it a certificate | Apple Silicon, Intel, universal |
| Linux | a folder with a yourgame launcher | x64, ARM64 |
| iOS | A ready Xcode project — icons, orientation, splash set | — |
| Android | A ready Android Studio project — icons, manifest, splash set | — |
Every desktop build is a folder, which is what Steam, itch.io and GitHub releases all expect. It opens the game in its own window with your name and icon — players never see a browser, a URL bar or a tab.
One machine, every platform
GemShell builds macOS and Linux versions on Windows, and Windows and Linux versions on a Mac. No virtual machines, no second computer, no build server. For iOS, Apple still requires a Mac to sign and upload the Xcode project.
What your game gains
- Its own window: size, fullscreen, always-on-top, minimum size, resizable or not — set in GemShell, no code needed.
- Desktop APIs from JavaScript: saving files, native open/save dialogs, the clipboard, OS detection. See the GemShell API.
- Steamworks, if you want it: achievements, cloud saves, lobbies and 137 calls more.
- Sealed assets: your files go into one encrypted bundle instead of sitting in a folder anybody can open.
How it runs
GemShell builds on Electron, so your game runs in Chromium — the same engine as Chrome. WebGL, WebAudio, gamepads and fonts behave exactly as they do in the browser you tested in, on every platform.
Questions
Does my game need changes?
No. GemShell packages the HTML5 export as it is. The desktop and Steam APIs are there if you want them, and a game that never calls them works just the same.
Can I sign the Windows and macOS builds?
Yes. Give GemShell your code-signing certificate and it signs the builds, so players do not see unknown-publisher warnings.