rune

Build multiplayer web games played by millions! You focus on your game, Rune handles everything else, incl. backend and networking Make your game using JavaScript / TypeScript and any frontend web framework such as React, Svelte, Vue, Threejs, PixiJS, Phaser. You can even use plain HTML and CSS. Perfect for web devs interested in gamedev. Maintained by rune on GitHub, where it has earned 422 stars from the community.

It's actively developed around css, framework, frontend, and is a solid reference for anyone building with these tools.