Paymaster

The Paymaster class is a utility class that provides methods for interacting with Paymaster contracts on the zkSync network. It supports two types of Paymasters: ERC20Paymaster and SponsoredPaymaster.

To call the methods of the Paymaster class, we need to first get the paymaster object.

getPaymaster

async function getPaymaster(address: Address, runner: Signer | Wallet): Promise<Paymaster>

Creates a new instance of the Paymaster class based on the provided Paymaster contract address.

• address: Address: The address of the Paymaster contract.

• runner: Signer | Wallet: A Signer or Wallet instance for signing and sending transactions.

• Returns: A new Paymaster instance.

Paymaster

The Paymaster class is a utility class that provides methods for interacting with Paymaster contracts on the zkSync network. It supports two types of Paymasters: ERC20Paymaster and SponsoredPaymaster.

Constructor

constructor(address: Address, runner: Signer | Wallet, paymasterType: PaymasterType, chainId: string, token?: Address)

• address: Address - The address of the Paymaster contract.

• runner: Signer | Wallet - A Signer or Wallet instance for signing transactions.

• paymasterType: PaymasterType - type of Paymaster (ERC20Paymaster or SponsoredPaymaster).

• chainId: string - The ID of the chain the Paymaster contract is deployed on.

• token: Address (optional) - The address of the ERC20 token used by the ERC20Paymaster.

populatePaymasterTransaction

async populatePaymasterTransaction(contractAddress: Address, functionToCall: InterfaceAbi, args?: any[], overrides?: PaymasterOverrides): Promise<TransactionRequest>

Populates a TransactionRequest object with the necessary data to call a function on a contract using the Paymaster.

• contractAddress: Address - The address of the contract to call.

• functionToCall: ethers.InterfaceAbi - The definition of the function to call. Can be:

  • Human-Readable fragment - string which resembles a Solidity signature and is introduced in this blog entry. For example, function balanceOf(address) view returns (uint).
  • Parsed JSON fragment - Fragment instances - JavaScript Object desribed in the Solidity documentation.
• args: any[] (optional) - An array of arguments for the function call.

• overrides: PaymasterOverrides (optional)- An object containing overrides for the transaction (e.g., to, value, data, customData, gasLimit, maxFeePerGas, maxPriorityFeePerGas)
• Returns: A TransactionRequest object populated with the transaction data.

getPaymasterCustomData

getPaymasterCustomData(paymasterOptions?: PaymasterOptions): PaymasterParams

Generates the PaymasterParams object that will be passed to the transaction that's using a paymaster.

• paymasterOptions: PaymasterOptions (optional) - An object containing options for the Paymaster (e.g., innerInput, minimalAllowance).
• Returns: A PaymasterParams object.

sendPaymasterTransaction

async sendPaymasterTransaction(contractAddress: Address, functionToCall: InterfaceAbi, args: any[] = [], overrides?: PaymasterOverrides): Promise<TransactionResponse>

Populates and sends a transaction using the Paymaster.

• contractAddress: Address - The address of the contract to call.

• functionToCall: ethers.InterfaceAbi - The definition of the function to call. Can be:

  • Human-Readable fragment - string which resembles a Solidity signature and is introduced in this blog entry. For example, function balanceOf(address) view returns (uint).
  • Parsed JSON fragment - Fragment instances - JavaScript Object desribed in the Solidity documentation.
• args: any[] (optional) - An array of arguments for the function call.

• overrides: PaymasterOverrides (optional)- An object containing overrides for the transaction (e.g., to, value, data, customData, gasLimit, maxFeePerGas, maxPriorityFeePerGas)
• Returns: A TransactionResponse object.

sendTransaction

async sendTransaction(tx: TransactionRequest): Promise<TransactionResponse>

Sends a populated TransactionRequest object using the Paymaster.

• tx: The TransactionRequest object to send.

• Returns: A TransactionResponse object.

getBalance

async getBalance(): Promise<BigNumberish>

Gets the balance of the Paymaster contract.

• Returns: The balance of the Paymaster contract as a BigNumberish value.

estimateGas

async estimateGas(tx: TransactionRequest): Promise<BigNumberish>

Estimates the gas required for a transaction. Especially tailored for Paymaster paymaster needs.

• tx: The TransactionRequest object for which to estimate the gas.

• Returns: The estimated gas limit as a BigNumberish value.

getPaymasterContract

getPaymasterContract(): ERC20Paymaster | SponsoredPaymaster

Gets an instance of the ERC20Paymaster or SponsoredPaymaster contract, depending on the paymasterType.

• Returns: An instance of the (ethers.Contract).

addRestriction

async addRestriction(address: Address): Promise<ContractTransactionResponse>

Adds a restriction to the Paymaster.

• address: Address - The address of the restriction contract to add.

• Returns: A ContractTransactionResponse object.

getRestrictions

async getRestrictions(): Promise<string[]>

Gets the list of restriction contract addresses added to the Paymaster.

• Returns: An array of restriction contract addresses.

removeRestriction

async removeRestriction(address: Address): Promise<ContractTransactionResponse>

Removes a restriction contract from the Paymaster.

• address: Address - The address of the restriction contract to remove.

• Returns: A ContractTransactionResponse object.

checkTransactionEligibility

async checkTransactionEligibility(contractAddress: Address, functionToCall: InterfaceAbi, args: any[] = [], overrides?: PaymasterOverrides): Promise<boolean>

Checks if a transaction is eligible to be paid for by the Paymaster, based on the added restrictions.

• contractAddress: Address - The address of the contract to call.

• functionToCall: ethers.InterfaceAbi - The definition of the function to call. Can be:

  • Human-Readable fragment - string which resembles a Solidity signature and is introduced in this blog entry. For example, function balanceOf(address) view returns (uint).
  • Parsed JSON fragment - Fragment instances - JavaScript Object desribed in the Solidity documentation.
• args: any[] (optional) - An array of arguments for the function call.

• overrides: PaymasterOverrides (optional)- An object containing overrides for the transaction (e.g., to, value, data, customData, gasLimit, maxFeePerGas, maxPriorityFeePerGas)
• Returns: true if the transaction is eligible, false otherwise.

getMinimalAllowance

async getMinimalAllowance(contractAddress: Address, functionToCall: InterfaceAbi, args?: any[], overrides?: PaymasterOverrides): Promise<BigNumberish>

Calculates the minimal allowance required for an ERC20Paymaster to pay for a transaction.

• contractAddress: Address - The address of the contract to call.

• functionToCall: ethers.InterfaceAbi - The definition of the function to call. Can be:

  • Human-Readable fragment - string which resembles a Solidity signature and is introduced in this blog entry. For example, function balanceOf(address) view returns (uint).
  • Parsed JSON fragment - Fragment instances - JavaScript Object desribed in the Solidity documentation.
• args: any[] (optional) - An array of arguments for the function call.

• overrides: PaymasterOverrides (optional)- An object containing overrides for the transaction (e.g., to, value, data, customData, gasLimit, maxFeePerGas, maxPriorityFeePerGas)
• Returns: The minimal allowance as a BigNumberish value.