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Release 2.4: Netplay

The latest version of WASM-4 now supports online multiplayer!

Hosting a netplay game is as easy as copy and pasting a link.

  1. While playing any cart, press Enter to open the WASM-4 menu.
  2. Select "Copy Netplay URL". An invite link (like will be copied to your clipboard for you to send to a friend.
  3. When your friend clicks your link, they'll instantly join your game as Player 2. No installation, no account creation, no configuration.

Try it out yourself with these multiplayer games:

Some details about how netplay works in WASM-4:

  • Fully peer-to-peer using WebRTC data channels.
  • Low-latency rollback netcode based on GGPO.
  • Works on both desktop and mobile web.
  • Supports up to 4 simultaneous players.
  • Players can join and leave at any time during gameplay.
  • The cart .wasm is automatically transferred to other players when they join. This means you can host your game anywhere, and even netplay games during development running on localhost.
  • No new APIs to learn. All WASM-4 games automatically support netplay. You can build online multiplayer games in just a few lines of code!


From the beginning, a goal of WASM-4 has been to unlock powerful technologies like WebAssembly for the average developer. With this release, we hope to extend that to WebRTC. I'm looking forward to seeing what people create!

To learn more, check out the Multiplayer documentation.