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Unreal Engine 5.9 ships a web platform: a project is compiled to WebAssembly and rendered through WebGPU, so it runs inside the viewer’s browser on the viewer’s own CPU, GPU and memory. No server is involved — the files sit on a static host and the browser downloads and runs them, the way an installed .exe would. Pixel streaming is the opposite arrangement: the project runs on a GPU server and the viewer receives a video stream and sends input back. The browser only has to play a video. Both put an Unreal project behind a link. They solve different problems. This page is the honest comparison, based on Epic’s own 5.9 documentation and what our customers’ viewers actually use.

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Side by side

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Which one fits

The web platform is a good fit when all of these are true
  • the project is small — a few hundred MB packaged — and lit without Lumen
  • the audience is on desktop Chrome or Edge, and losing phone, iPad, Mac/Safari viewers is acceptable
  • a different look on different machines is acceptable
  • the content can be public — anyone can keep the downloaded files
  • you build the engine from source and can maintain a separate web pipeline
Stream the project when any of these is true
  • viewers are on phones, tablets, Macs or in Safari (for a typical product configurator, roughly a third of viewers are on a phone)
  • the project uses Lumen, Nanite, ray tracing or is more than about a gigabyte
  • the first frame has to appear in seconds, from a link in an email or a QR code
  • the picture has to be the same for every viewer — a brand experience, a client review, a configurator
  • the assets are confidential or unreleased
  • you need sign-in, allowed domains, session analytics or a webhook when a build is ready
  • the project is multiplayer, uses voice, or depends on plugins that are not ported to WebAssembly

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Can a project do both?

Not from one build today. The web platform is a separate cook, and the Pixel Streaming plugins do not build for WebAssembly, so a project that wants a web build and a stream maintains two packages. If you are weighing that, talk to us — the useful combination is one link that serves whichever the viewer’s device can run.

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Where this comes from

The web-platform facts above are from Epic’s 5.9 documentation (Engine/Platforms/Wasm/Docs in the engine source: the support matrix, performance and shipping pages). 5.9 is the platform’s first release and Epic marks it experimental; browser support and renderer features will change with later versions. We will keep this page current.