Skip to content

Working with Auction

Expload Auction is a universal market platform for all games on Expload platform. Expload Auction (together with TradableAsset) provides a united interface for in-game integration and interaction.

Program structure

Lot class

Represents a lot on the Auction. Attributes:

  • UInt32 Id - blockchain id of the lot
  • Bytes Creator - address lot creator
  • UInt32 GameId - id of the game asset being sold is from
  • UInt32 AssetId - blockchain id of the asset sold (see TradableAsset docs)
  • Bytes ClassId - class id of the asset sold
  • UInt32 Price - price of the lot
  • bool Closed - if the lot was already sold or closed by its creator
  • Bytes Buyer - null if asset hasn't been sold yet, buyer's address otherwise

Lot storage

The storage is split into three parts:

  • Main lot data storage. Each lot has its unique lot id, which is given when a lot is created. LotId = 0 is invalid.
  • You can get any lot data by its lot id by calling GetLotData method, which returns lot object.
  • User lot storage, which allows you to get lots created by a particular user.
  • You can get a list of user's lots by calling GetUserLotsData method.
  • Asset lot storage, which allows you to get lots selling an asset with particular game id.
  • You can get a list of lots selling a particular in-game item by calling GetAssetLotsData method.

Interacting with the storage

There are 3 ways to interact with the storage:

  • Create a lot with CreateLot method. When this method is called, lot id is returned and lotCreated event is emitted. Also, the asset to be sold is transferred from lot creator to auction's wallet.
  • Buy a lot with BuyLot method. When the method is called, asset is transferred to buyer and funds to lot creator, lotBought event is emitted.
  • Close a lot with CloseLot method. When a lot is closed, the asset is returned to lot creator and the lot can't be bought anymore. Closed lot is not shown in Expload Auction UI and can't be reopened.

Integrating your game

Before working with Expload Auction, make sure your game is featuring an implementation of TradableAsset! Expload Auction is only available to certified providers, so you are to contact if your game doesn't have a unique game id for Expload Auction yet.

  1. Set up TradableAsset Use SetAuction method in TradableAsset to provide an up-to-date auction address.
  2. Integrate into UI

    To interact with Auction from your game's client, use DApp API. Further description will only feature contract methods and will not focus on working with DApp API.

Use api/program/method-test with methods which only receive data from the auction and do not change the state of the contract. This will save watts and result in a better performance of the app. However, if you are to create, buy or close lots use api/program/method only, as otherwise changes will not be saved in blockchain.

If you still have questions, take a look at comments and docstrings in Auction.cs or contact us at