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The Immutable SDK exposes all functionality to Blueprints, enabling full integration without C++ code.

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Getting Started

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Access the Immutable Subsystem

The ImmutableSubsystem is your entry point for all SDK operations: 
Event BeginPlay
    └── Get Game Instance
        └── Get Subsystem (Class: ImmutableSubsystem)
            └── Store as variable "Immutable"

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Initialize the SDK

Call Initialize before any other operations: 
Event BeginPlay
    └── Immutable → Initialize

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Authentication

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Login Flow

Event OnLoginButtonClicked
    └── Immutable → Login
        ├── On Success → Set "WalletAddress" variable
        │              └── Update UI
        └── On Failure → Show error message

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Check Existing Session

For returning users: 
Event BeginPlay
    └── Immutable → Is Logged In
        ├── True → Skip to main menu
        └── False → Show login screen

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Get Wallet Address

Immutable → Get Wallet Address
    └── Store as "WalletAddress"

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Logout

Event OnLogoutButtonClicked
    └── Immutable → Logout
        └── On Complete → Return to login screen

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Wallet Operations

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Get User Info

Immutable → Get User Info
    ├── On Success → Display email, user ID
    └── On Failure → Handle error

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Send Transaction

Make Transaction Request
    ├── To: "0xRecipient..."
    ├── Value: "1000000000000000000"  (1 IMX in wei)
    └── Data: "0x"

Immutable → Send Transaction (Request)
    ├── On Success → Show "Transaction: {TxHash}"
    └── On Failure → Show error

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Sign Message

Immutable → Sign Message ("Hello World")
    ├── On Success → Use signature
    └── On Failure → Handle error

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Indexer Queries

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Get Player’s NFTs

Immutable → List NFTs By Owner (WalletAddress, ContractAddress)
    ├── On Success → For Each NFT
    │              └── Create inventory slot widget
    │                  └── Set NFT data (Name, Image, TokenId)
    └── On Failure → Show error

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Get Collection Info

Immutable → Get Collection (ContractAddress)
    ├── On Success → Display collection name, total supply
    └── On Failure → Handle error

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Orderbook (Alpha)

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List NFTs for Sale

Immutable → List Listings (ContractAddress, Status: Active)
    ├── On Success → For Each Listing
    │              └── Create marketplace card
    │                  └── Set price, seller, token info
    └── On Failure → Show error

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Create Listing

Make Prepare Listing Request
    ├── Maker Address: WalletAddress
    ├── Sell: ERC721 Item (Contract, TokenId)
    └── Buy: Native Item (Amount in wei)

Immutable → Prepare Listing (Request)
    └── On Success → Sign Typed Data
                    └── Create Listing (with signature)
                        └── Show "Listing created"

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Buy NFT

Immutable → Fulfill Order (ListingId, BuyerAddress)
    └── On Success → For Each Action
                    └── If Action Type == Transaction
                        └── Send Transaction
                            └── Wait for confirmation

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UI Patterns

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Inventory Grid

Widget Blueprint: W_InventoryGrid

Event Construct
    └── Load Inventory

Function: Load Inventory
    └── Clear Grid
    └── Immutable → List NFTs By Owner
        └── On Success → For Each NFT
                        └── Create Widget (W_InventorySlot)
                        └── Add to Scroll Box

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Marketplace Listing Card

Widget Blueprint: W_ListingCard

Variables:
- ListingId (String)
- TokenId (String)
- Price (String)
- SellerAddress (String)

Function: Set Data (Listing)
    └── Set ListingId = Listing.Id
    └── Set TokenId = Listing.Sell.TokenId
    └── Set Price = Format as IMX
    └── Set SellerAddress = Listing.AccountAddress
    └── Load image from Listing.Sell.ImageUrl

Event OnBuyClicked
    └── Buy NFT (ListingId)

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Error Handling

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Generic Error Handler

Function: Handle Immutable Error (Error Message)
    └── Print String: Error Message
    └── Show UI notification
    └── Log to analytics (optional)

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Retry Pattern

Function: Login With Retry (Attempts Remaining)
    └── If Attempts Remaining <= 0
        └── Show "Login failed" → Return
    └── Immutable → Login
        ├── On Success → Continue to game
        └── On Failure → Delay 2 seconds
                        └── Login With Retry (Attempts - 1)

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Best Practices

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Store Subsystem Reference

Get the subsystem once and store it: 
Event BeginPlay
    └── Get Immutable Subsystem
    └── Store as variable (Immutable)
    └── Use variable for all subsequent calls

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Handle Loading States

Show feedback during async operations: 
Event OnLoginClicked
    └── Set "IsLoading" = True
    └── Disable login button
    └── Immutable → Login
        ├── On Success → Set "IsLoading" = False
        │              └── Enable button
        └── On Failure → Set "IsLoading" = False
                        └── Enable button

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Validate Before Operations

Check prerequisites before calling SDK: 
Function: Create Listing
    └── Is Valid (WalletAddress)?
        ├── False → Show "Please login first" → Return
        └── True → Continue with listing creation

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Debugging Blueprints

  1. Print String nodes at key points
  2. Use Breakpoints (F9) on nodes
  3. Check Output Log for SDK messages
  4. Enable Blueprint Debugger in editor

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Next Steps

C++ Integration

Mix Blueprints with C++

FAQ

Common questions