How do I avoid performance issues with large data in Foundry VTT?

For datasets larger than 100KB, store the data in an external JSON file using the FilePicker API and save a reference to the file path in a flag or setting rather than the data itself.

What is the correct way to update multiple flags at once?

Instead of calling setFlag() multiple times, use the document.update() method with nested flag keys (e.g., 'flags.my-module.key') to perform a single database write.

Why is namespacing important for Foundry VTT flags?

Namespacing prevents data collisions between different modules. Always use your unique module ID as the scope when setting or getting flags to ensure data integrity.

When should I use Flags instead of Settings in Foundry VTT?

Use Flags for data attached to a specific document (like an Actor, Item, or Scene) that needs to travel with that document. Use Settings for global module configuration or per-client UI preferences.

Foundry VTT Data Storage

Name: Foundry VTT Data Storage
Author: ImproperSubset

byImproperSubset

0•

Game Development

Optimizes data management strategy in Foundry VTT using standardized patterns for flags, settings, and file storage.

The fvtt-data-storage skill provides specialized guidance for developers building modules and systems on the Foundry Virtual Tabletop platform. It streamlines the decision-making process between using Document Flags for actor-specific data, Module Settings for global configurations, and external Files for large datasets. By enforcing best practices like proper namespacing, batch updates via document.update(), and efficient lazy-loading patterns, this skill helps developers avoid common performance bottlenecks and database corruption issues while ensuring cross-version compatibility.

Key Features

01High-performance batch update techniques for document flags

02Data migration workflows for module schema updates

03Decision matrix for selecting Flags, Settings, or File storage

040 GitHub stars

05Namespacing patterns to prevent module data collisions

06Complex settings registration with FormApplication menus

Use Cases

01Creating persistent GM configuration menus for module behavior

02Implementing custom character sheet attributes via Actor flags

03Offloading large datasets to external JSON files to maintain VTT performance

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add impropersubset/hh-agentics fvtt-data-storage

For use in Claude.ai and ChatGPT

Download Skill