As all your Asset data must be pre-downloaded before your content starts, you should consider moving Assets out of your main data files and into AssetBundles. This lets you create a small loader SceneA Scene contains the environments and menus of your game. Think of each unique Scene file as a unique level. In each Scene, you place your environments, obstacles, and decorations, essentially designing and building your game in pieces. More info
See in Glossary for your content which loads quickly and dynamically loads Assets on-demand as the user proceeds through your content. AssetBundles also help with Asset data memory management: You can unload Asset data from memory for Assets that you don’t need any more by calling AssetBundle.Unload.
The following considerations apply when using AssetBundles on the Web platform:
When you use class types in your AssetBundle which aren’t used in your main build, Unity may strip the code for those classes from the build. This can cause a fail when trying to load Assets from the AssetBundle. Use BuildPlayerOptions.assetBundleManifestPath to fix that, and see Distribution size and code stripping for other options.
The WebGLA JavaScript API that renders 2D and 3D graphics in a web browser. The Unity Web build option allows Unity to publish content as JavaScript programs which use HTML5 technologies and the WebGL rendering API to run Unity content in a web browser. More info
See in Glossary graphics API doesn’t support threading. As Http downloads become available only after they’re downloaded, Unity Web platform builds need to decompress AssetBundle data on the main thread after the download is complete, blocking the main thread. To avoid this interruption, LZMA AssetBundle compression isn’t available for AssetBundles on Web. AssetBundles are compressed using LZ4 instead, which is de-compressed efficiently on-demand. If you need smaller compressionA method of storing data that reduces the amount of storage space it requires. See Texture Compression, Animation Compression, Audio Compression, Build Compression.
See in Glossary sizes than LZ4 delivers, you can configure your web server to use gzip or Brotli compression (on top of LZ4 compression) on your AssetBundles. See documentation on Deploying compressed builds for more information on how to do this.
the Web platform does not support file-system based AssetBundle caching with UnityWebRequestAssetBundle.GetAssetBundle. Instead the WebRequest responses are cached by the browser, see Cache behavior in Web for details. This means that the entire AssetBundle file is held in memory when an AssetBundle is loaded, and care must be taken to promptly unload unused AssetBundles, especially when they are large.