Box3JS

Creators can use Box3JS to make minigames, RPG-style progression and changes to how the world behaves, all driven by scripts instead of Java. Scripts are written in TypeScript, and the mod ships full .d.ts type declarations with bilingual JSDoc, so an editor can offer auto-completion. Scripts reload within seconds while the server runs, and the Box3-compatible API covers the world, entities, players, voxels, storage, a database, HTTP and a remote channel. More than 110 Minecraft extensions are exposed as well, including scoreboards, boss bars, teams, world border control, particles, fireworks and potions, along with registration of blocks, items and sounds.

The mod has a server-side part and a client-side part. On the client, scripts can draw a custom HUD, read keyboard input, play audio, and use a local SQLite database and HTTP access. Each script project runs in its own isolated scope with its own callbacks, so several projects can run together without interfering. A sandbox mode lets a script be tested safely, and changes a script made to the world can be rolled back. Finished scripts are packaged into a distributable JAR with the box3script compile command.

Box3JS is open source under the Apache License 2.0 and is published for NeoForge on 1.21.1 only, with 0.1.0-neoforge-mc1.21.1-beta as the latest file in the beta channel. It is classed as a library and utility mod. Either side can run it, and neither side needs it.