Managing Worlds, Game Systems, and Modules

Overview

Foundry VTT organizes its content into three package types: game systems, modules, and worlds. Each type is stored in a separate subdirectory of your data path and is managed through the Setup menu. Understanding how these are stored is important for backups, migrations, and storage planning.

Directory Layout

All package data lives under the Data/ subdirectory of your data path:

/foundry-data/Data/
  worlds/
    my-campaign/
      world.json
      data/
      scenes/
  systems/
    dnd5e/
    pf2e/
  modules/
    dice-so-nice/
    token-magic-fx/

Game Systems

A game system is required before you can create a world. Systems define the rules, character sheets, and mechanics (e.g., D&D 5e, Pathfinder 2e, Call of Cthulhu).

Installing a system:

1. Access the Setup menu
2. Click "Install Package"
3. Select the "Game Systems" tab
4. Search for the system by name
5. Click "Install"

Foundry downloads the system from the Foundry package repository. Systems typically range from 5 MB to 50 MB.

Removing a system:

In the Setup menu, find the system under "Game Systems" and click the delete button. You cannot delete a system that has active worlds using it — delete or move those worlds first.

Worlds

A world is a single campaign or game instance. Only one world can be active (running) at a time on a server instance. Each world is tied to a specific game system.

Creating a world:

1. Setup menu → "Create World"
2. Select a game system (must be installed first)
3. Enter a world title and other metadata
4. Click "Create World"

World storage:

Worlds are the largest data type. A new empty world is small, but worlds with maps, audio, and tokens can grow to 50 MB–10+ GB. Plan storage accordingly.

/foundry-data/Data/worlds/<world-name>/
  world.json        ← world metadata and configuration
  data/             ← actors, items, journal entries (database files)
  scenes/           ← scene data

Launching a world:

From the Setup menu, click the "Launch" button next to a world. The server transitions to the active world; players can then connect.

Modules

Modules are optional add-ons that enhance gameplay — dice rollers, map tools, token effects, and more. They are activated per-world, not globally.

Installing a module:

1. Setup menu → "Install Package"
2. Select the "Add-on Modules" tab
3. Search and install

Modules range from under 1 MB to over 500 MB (some include large asset packs). Monitor your storage when installing media-heavy modules.

Activating a module in a world:

1. Launch a world
2. Navigate to Settings → Manage Modules
3. Enable the desired modules and save
4. The world reloads with modules active

Updating packages:

Setup menu → click the update icon next to any package, or use "Update All" to update all installed packages at once. Always back up before bulk-updating. See Backing Up and Restoring Your Foundry Data.

Storage Planning

As a rough guide for storage estimation:

Monitor disk usage with:

du -sh /foundry-data/Data/worlds/*
du -sh /foundry-data/Data/modules/*

Related

• Backing Up and Restoring Your Foundry Data
• Updating Foundry VTT
• Performance Tuning and Player Capacity
• Troubleshooting Common Foundry VTT Issues