Introducing Opal's GraalVM Scripting Engine

Opal ships a GraalVM JavaScript engine, a full JS runtime running inside the Minecraft client. You write scripts that talk to Opal's internal APIs while the game is live. This is not a macro recorder or a keybind system. It is a real programming environment with access to the client's event system, module configs, and game state.

Why GraalVM

GraalVM is a polyglot runtime from Oracle. We picked it for concrete reasons:

• Speed: JIT compilation keeps scripts fast enough to run every tick.
• JavaScript: most people already know it, so the learning curve is short.
• Thread safety: the JS-to-Java bindings handle concurrency properly instead of leaving you to trip over it.
• Familiar patterns: standard JavaScript APIs behave the way you expect.

What you can build

Custom automation

Respond to in-game events:

// Auto-respond to certain chat messages
on('chat', (event) => {
  if (event.message.includes('1v1?')) {
    sendChat('/duel accept');
  }
});

Dynamic module configuration

Change module settings based on game state:

// Increase reach when health is low
on('tick', () => {
  const health = player.getHealth();
  if (health < 8) {
    modules.get('Reach').setSetting('distance', 3.3);
  } else {
    modules.get('Reach').setSetting('distance', 3.1);
  }
});

Custom HUD elements

Draw your own overlays:

// Display a combo counter on screen
let combo = 0;
on('attackEntity', () => { combo++; });
on('damage', () => { combo = 0; });
on('render2d', (ctx) => {
  ctx.drawText(`Combo: ${combo}`, 10, 10, 0xFFFFFF);
});

Server-specific profiles

Switch configs automatically when you join different servers:

on('serverJoin', (event) => {
  if (event.ip.includes('pvp.example.com')) {
    loadConfig('server-bypass');
  } else {
    loadConfig('ghost-default');
  }
});

Getting started

Community scripts

The scripting community is growing. The Discord has shared scripts and people to help you write your own. Common ones include auto-game scripts for minigames, stat trackers, combo detection, and server-specific config switchers.

FAQ