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To use paymaster you simply need to pass a ERC-20 token that you want a user to pay a gas with Currently paymaster is integrated to several operations with the SDK:
  1. Send a transaction
  2. Deposit funds to a DeFi opportunity (earn() method)
  3. Withdraw funds to a DeFi opportunity (withdraw() method)

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How to use a paymaster?

Here is a quick exmaple how to sponsor gas during the depositing a user funds to DeFi opportunity
1

Init SDK

import { MyceliumSDK } from '@mycelium-sdk/core';


const sdk = await MyceliumSDK.init({
    apiKey:
      "sk_e010bc44958665229cb89634448f81f532231ce131c4eb98816eadcb2e6ed7fa47",
    chainId: 8453,
    protocolsSecurityConfig: {
      riskLevel: "low",
    },
  });
2

Get a vault to depoist

const vaults = await sdk.protocols.getBestVaults()
3

Get or create a user wallet

const wallet = await this.sdk.wallet.createAccount()
4

Deposit using paymaster

Make sure that the smart wallet have enough token balance that you pass to paymaster for gas sponsoringIf the gas token will be the same token that you’re depositing, you need to check that a user will leave at leas small portion on the wallet to complete the deposit AND make a withdrawal later onCheck more exmples of this use case below
const USDC_TOKEN_ADDRESS = "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"

const txnHash = await wallet.earn(
	selectedVault.vaultInfo, 
	amountToDeposit, 
	{
      paymasterToken: USDC_TOKEN_ADDRESS,
    }
);

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Reserved gas amount

In some cases you want to use for gas sponsring the same ERC-20 token that you’re using for a deposit to a DeFi opportunity For example, you want to deposit 100 USDC to a vault. In this case, you need to care that a user will still have some small portion of USDC on the smart wallet to perform the deposit action as well as withdrawal later on In case of L2 networks, the gas price will be small on 0.01 USDC should be enough to cover 1 operation with gas sponsoring For some L1 networks (e.g. Ethereum) gas can be significantly higher and you need to care that user would have enought ERC-20 token to cover the gas fee The same will be with ERC-20 tokens with decimals > 6, e.g. ETH or BTC. In this case, you can reserve at least 1% of the token for the further gas fee, so a user can successfully complete onchain operations