These are answers to common questions about developing Playables.
General technical
These are FAQ about general technical topics.
What game engines can I use?
YouTube Playables supports standard web platform APIs. Therefore, Playables supports games made with game engines that export builds for the web that use a standard rendering API (for example, WebGL and Canvas). Engines and frameworks that have been used for Playables in the past include BabylonJS, Cocos, Construct, Defold, melonJS, Phaser, PixiJS, PlayCanvas, React, three.js, Godot, and Unity.
How do I test on foldable phone simulators?
For rapid testing, see Chrome Dev Tools supports simulating a foldable phone. Additionally, there are several emulator options in Android Studio that can be used for more thorough testing.
How can I test on mobile WebViews?
You can use third-party apps like WebView Tester (Android) or WebView - Tester (iOS) to open your game or the SDK test suite in a WebView for additional validation. Since this is third-party software that is not supported or validated by Google, you can also use open-source options, such as WebView Tester (Android) or swift-ios-wkwebview-demo (iOS) to compile your own WebView testing apps.
How does the game run inside of YouTube?
Standard web and mobile technology is used to run Playables within the YouTube mobile and web apps. As a result, Playables supports standard web platform APIs.
This diagram shows a brief technical overview:
What memory usage restrictions exist for Playables on YouTube?
Games can only use up to 512 MB of JavaScript heap size. Playabes are run within Safari on iOS and this is the threshold at which the game will frequently crash and reload the browser. You can measure the heap size the game is using at any time using Chrome DevTools to record heap snapshots
How does a game go "live"?
We're careful about rolling out Playables to users, so we perform various stages of Playables validation to verify that YouTube and the individual Playable work well together. This may include limited access, staged rollouts, or adjustments using our automated systems.
Once your Playable is certified and published, you should expect to support full game usage irrespective of any of these rollout mechanisms. You should also expect fluctuations in user engagement at any time.
Other questions
If you are an existing Playables developer, additional FAQ are available.