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Steam Inventory

The Steam Inventory Service stores items for each player on Steam, for example cosmetics, crates or crafting materials. This guide uses the SteamCore|Inventory nodes.

Prerequisites​

  • Your own Steam App ID, see Using Your Own App ID.
  • Steam is running and the game is launched as a Standalone Game or a packaged build.

Step 1: Define Your Items​

  1. On the Steamworks partner site, go to Community → Inventory Service and enable it.
  2. Upload your item definitions (a JSON file). Each item has a numeric itemdefid and properties such as name, description and icon_url. See Valve's item schema documentation.
  3. Publish the changes.

How Results Work​

Most inventory nodes do not return items directly. They return a result handle, and Steam fires an event when the result is ready:

  1. Call a node such as Get All Items. It returns a Steam Inventory Result.
  2. Use Get Steam Inventory and bind Steam Inventory Result Ready. When it fires, compare Handle with the handle you got and check Result.
  3. Call Get Result Items with the handle. Each item has an Instance ID, a Definition (the itemdefid) and a Quantity.
  4. Call Destroy Result with the handle when you are done.

Listing the Player's Items​

Call Get All Items and handle the result as described above. Steam Inventory Full Update also fires with the complete inventory.

To show names and icons, call Load Item Definitions once, then Get Item Definition Property with the item's Definition and a property name such as name or icon_url. Steam Inventory Definition Update fires when the definitions are loaded or change.

Granting Items​

NodeUse it for
Add Promo Item / Add Promo ItemsGiving a promo item, for example a reward for owning another game. The item must be a promo item in your definitions.
Grant Promo ItemsGranting all promo items the player is eligible for.
Trigger Item DropPlaytime drops. The definition must be a playtimegenerator.
Generate ItemsTesting only. It only works for accounts with access to the app in Steamworks.

Using and Combining Items​

  • Consume Item removes a quantity of an item, for example when a consumable is used.
  • Exchange Items turns items into another item using an exchange recipe from your item definitions, for example for crafting.
  • Transfer Item Quantity splits or stacks items.
  • Start Update Properties, Set Property String/Bool/Int/Float and Submit Update Properties change dynamic properties on an item.

All of these return a result handle that you handle as described in How Results Work.

Verifying Items on a Server​

The client's inventory can be modified by cheaters. If items matter for gameplay, verify them on your server:

  1. On the client, call Serialize Result with the result handle and send the bytes to the server.
  2. On the server, call Deserialize Result with the bytes.
  3. When the result is ready, call Check Result Steam ID with the player's Steam ID. Only trust the items if it returns true.

Selling Items​

Items can be sold with Steam's in-game purchase flow:

  • Request Prices loads the prices in the player's currency. Then use Get Items With Prices or Get Item Price.
  • Start Purchase opens the Steam purchase dialog for a list of item definitions.

For purchases handled by your own backend, see Microtransactions.