Inventory Systems in Roblox
Design item storage, equipping, stacking, and trading with ModuleScript architecture.
Introduction
Inventory systems manage what players own and can use. A well-designed inventory separates data (what items exist), storage (where they live), and presentation (how the UI displays them). This hub walks through a modular inventory architecture suitable for RPG, simulator, and adventure games.
Inventory Data Model
Represent items as tables: { id = 'sword_iron', quantity = 1, metadata = {} }. Store inventories as arrays of item tables in player data. Use a ItemDatabase ModuleScript as the source of truth for item definitions—name, icon, max stack, equip slot.
Equip and Unequip Flow
Server validates equip requests. Clone tool model from ServerStorage to Backpack. Track equipped item ID in player data. On unequip, destroy tool instance and update data. Fire client event to refresh UI.
Use Cases
- RPG item management
- Simulator collectibles
- Trading systems
Best Practices
- Single source of truth for item definitions
- Server-authoritative add/remove operations
- Validate item existence before equipping
Troubleshooting
Script runs but nothing happens in-game
Verify the script type matches its location. Server Scripts belong in ServerScriptService; LocalScripts in StarterPlayerScripts or StarterGui. Check the Output window in Studio for error messages.
Changes don't appear after editing
Stop and restart Play mode in Studio. Some scripts cache values on first run. For published games, republish after testing locally.