Send transactions with Passport

Learn how to send blockchain transactions using Immutable Passport in your Unreal game.

Overview

Passport provides two methods for sending transactions on zkEVM:

1. ZkEvmSendTransactionWithConfirmation (Recommended) - Waits for transaction confirmation
2. ZkEvmSendTransaction - Returns immediately with transaction hash

💡Token Restrictions

Games can only use ERC-20 tokens issued by the game itself, meaning currencies like ETH, USDC, IMX, USDT, etc. cannot be used in-game.

Prerequisites

📋Prerequisites

• The zkEVM send transaction requires pre-approval.
• Must have first called ConnectEvm to set up the zkEVM provider and ZkEvmRequestAccounts to login the user.

Implementation

To send a transaction on zkEVM, use UImmutablePassport::ZkEvmSendTransaction or UImmutablePassport::ZkEvmSendTransactionWithConfirmation methods. You need to provide three parameters:

• to: The destination address
• value: The value to transfer for the transaction in wei
• data: Byte string containing the associated data of the message

💡Gas Properties

This method does not support the gas, gasPrice, maxPriorityFeePerGas, or maxFeePerGas properties as the relayer abstracts these away from the user. Additionally, the from property is not supported as the user's Passport wallet address is used instead.

(Recommended) With Confirmation

Sends a transaction to the network, signs it using the logged-in Passport account, and waits for the transaction to be included in a block.

Without Confirmation

Sends a transaction to the network and signs it using the logged-in Passport account.

💡Transaction Status

It's important to note that obtaining the transaction hash does not guarantee a successful transaction. To determine the transaction's status, use ZkEvmGetTransactionReceipt along with the transaction hash received.

In cases where the transaction is still being processed, ZkEvmGetTransactionReceipt returns no receipt data. Once the transaction is processed, ZkEvmGetTransactionReceipt returns receipt data with a status of 0x1 (success) or 0x0 (failure).

💡Polling Best Practices

It is recommended to follow best practices for client-side polling, including setting maximum attempts, defining appropriate polling intervals, and knowing when to pause or resume polling.

See here for more details.

Related Methods

• ZkEvmGetBalance - Gets the balance of the given address in wei
• ZkEvmGetTransactionReceipt - Retrieves transaction information for a given transaction hash

Next Steps

After sending transactions, you might want to:

• Sign typed data for message verification
• Check the API Reference for additional blockchain methods