​
Import

import { useWaasFeeOptions } from '@0xsequence/connect'

​
Usage

import { useWaasFeeOptions } from '@0xsequence/connect'
import { useEffect, useState } from 'react'

function App() {
  // Use the hook with default balance checking
  // This will return the wallet balance for each fee option
  const [
    pendingFeeOptionConfirmation,
    confirmPendingFeeOption,
    rejectPendingFeeOption
  ] = useWaasFeeOptions()
  
  // Or skip balance checking if needed
  // const [pendingFeeOptionConfirmation, confirmPendingFeeOption, rejectPendingFeeOption] =
  //   useWaasFeeOptions({ skipFeeBalanceCheck: true })
  
  const [selectedFeeOptionTokenName, setSelectedFeeOptionTokenName] = useState<string>()
  
  // Initialize with first option when fee options become available
  useEffect(() => {
    if (pendingFeeOptionConfirmation) {
      console.log('Pending fee options: ', pendingFeeOptionConfirmation.options)
      
      // You could select the first fee option by default
      if (pendingFeeOptionConfirmation.options.length > 0) {
        const firstOption = pendingFeeOptionConfirmation.options[0]
        setSelectedFeeOptionTokenName(firstOption.token.symbol)
      }
    }
  }, [pendingFeeOptionConfirmation])
  
  // Handle fee option selection and confirmation
  const handleConfirmFee = (tokenAddress: string | null) => {
    if (pendingFeeOptionConfirmation) {
      confirmPendingFeeOption(pendingFeeOptionConfirmation.id, tokenAddress)
    }
  }
  
  // Handle fee option rejection
  const handleRejectFee = () => {
    if (pendingFeeOptionConfirmation) {
      rejectPendingFeeOption(pendingFeeOptionConfirmation.id)
    }
  }
  
  // Render fee options UI
  if (pendingFeeOptionConfirmation) {
    return (
      <div>
        <h2>Select Fee Payment Token</h2>
        <div>
          {pendingFeeOptionConfirmation.options.map((option) => (
            <div key={option.token.symbol || option.token.contractAddress}>
              <input
                type="radio"
                name="feeOption"
                checked={selectedFeeOptionTokenName === option.token.symbol}
                onChange={() => setSelectedFeeOptionTokenName(option.token.symbol)}
              />
              <label>
                {option.token.symbol} - {option.token.contractAddress ? 
                  option.token.contractAddress : 'Native Token'}
                {/* Display balance info if extended with balance data */}
                {'balanceFormatted' in option && 
                  ` (Balance: ${option.balanceFormatted} ${option.token.symbol})`}
              </label>
            </div>
          ))}
        </div>
        <div>
          <button onClick={() => handleConfirmFee(
            pendingFeeOptionConfirmation.options.find(
              opt => opt.token.symbol === selectedFeeOptionTokenName
            )?.token.contractAddress || null
          )}>
            Confirm
          </button>
          <button onClick={handleRejectFee}>Cancel</button>
        </div>
      </div>
    )
  }
  
  return <div>No pending fee confirmation</div>
}

​
Parameters

The hook accepts an optional configuration object with the following properties:

interface WaasFeeOptionsConfig {
  skipFeeBalanceCheck?: boolean
}
ParameterTypeDescription
skipFeeBalanceCheckbooleanWhether to skip checking token balances (default: false)

​
Return Type: UseWaasFeeOptionsReturnType

The hook returns a tuple with the following elements:

type UseWaasFeeOptionsReturnType = [
  pendingFeeOptionConfirmation: WaasFeeOptionConfirmation | undefined,
  confirmPendingFeeOption: (id: string, feeTokenAddress: string | null) => void,
  rejectPendingFeeOption: (id: string) => void
]

​
Properties

​
pendingFeeOptionConfirmation

WaasFeeOptionConfirmation | undefined

Object containing the current fee confirmation details if a transaction is pending, or undefined if no transaction is pending confirmation.

type WaasFeeOptionConfirmation = {
  id: string                                // Unique identifier for the fee confirmation
  options: FeeOptionExtended[] | FeeOption[] // Available fee options with balance information
  chainId: number                           // Chain ID where the transaction will be executed
}

When skipFeeBalanceCheck is false, the options will be of type FeeOptionExtended, which includes balance information:

type FeeOptionExtended = FeeOption & {
  balance: string               // Raw balance string
  balanceFormatted: string      // Formatted balance with proper decimals
  hasEnoughBalanceForFee: boolean // Indicates if wallet has enough balance
}

​
confirmPendingFeeOption

(id: string, feeTokenAddress: string | null) => void

Function to confirm the selected fee option.

ParameterTypeDescription
idstringThe fee confirmation ID
feeTokenAddressstring | nullThe address of the token to use for fee payment (use null for native token)

​
rejectPendingFeeOption

(id: string) => void

Function to reject the current fee option selection.

ParameterTypeDescription
idstringThe fee confirmation ID to reject

​
Notes

This hook provides functionality for handling WaaS (Wallet as a Service) fee options for unsponsored transactions.

Key features:

  • Get available fee options for a transaction in Native Token and ERC20 tokens
  • Automatically fetch user wallet balances for each fee option (unless skipFeeBalanceCheck is true)
  • Allow users to select their preferred fee token
  • Confirm or reject fee selections

The hook integrates with the Sequence WaaS provider to intercept fee confirmation requests and presents a user interface to allow selection of the fee token.

For a detailed guide on how to use the hook, see the Pay gas in ERC20 guide.

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