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WASM-4 Jam 2 in August

I'm pleased to announce the second WASM-4 game jam, in partnership with our friends at Wasmer!

As previously, the main goal of the game jam is to have fun and learn new things. That being said, this time around the deal is being sweetened with a $2500 prize pool!

A panel of judges from across the WebAssembly community will rate games along four categories:

  • Fun: How much you enjoyed your time playing the game.
  • Concept: How interesting or unique the main focus of the game is.
  • Polish: How well executed and presented the main focus of the game is.
  • Tech: How impressive the game is at a technical level.

The jam will run between August 12 and 21, and you can sign up on and see more details!

Our first game jam at the beginning of the year was a surprising success, with 138 signups and 44 entries. Despite WASM-4 being brand new, a lot of people turned up from various communities all interested in one thing: building small. Since the first jam, WASM-4 has added a couple features (like online multiplayer). However, the core philosophy of the project is still that when it comes to technology, often less is more. We hope you join our little community, and I can't wait to see what you build!

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.