Paymaster SDK Tutorial (Typescript)

Install the paymaster SDK

npm install @kanalabs/paymaster-sdk
or
yarn add @kanalabs/paymaster-sdk

Initialize SDK with Private Key and projectKey

import { PaymasterSdk } from "@kanalabs/paymaster-sdk";
const sdk = new PaymasterSdk(
  {
    privateKey:
      "user private key", // Optional
  },
  { 
    projectKey: "your project key", 
    network: Network.TESTNET // default MAINNET 
  }
);

Initialize SDK without Private Key

import { PaymasterSdk } from "@kanalabs/paymaster-sdk";
const sdk = new PaymasterSdk({}, { projectKey: testProjectKey, network: Network.TESTNET })

Check If user already whitelisted,

const isWhitelisted = await sdk.isWhitelisted();

// Response format
{
    success: boolean;
    message: string;
}

It will return { success: true, message: 'whitelisted' } if already whitelisted.

It will return { success: true, message: 'not whitelisted' } if it is not whitelisted.

To add user to whitelist

const whitelist = await sdk.addToWhitelist();
// Response format
{
    success: boolean;
    message: string;
}

It will return { success: true, message: 'Successfully added' } if successfully whitelisted.

It will return { success: true, message: 'already whitelisted' } if user already whitelisted.

Initialize user account

if that account is not available in Aptos mainnet you can initialize account with the following function.

const initAccount = await sdk.initAccount();
// Response format
{
    success: boolean;
    message: string;
}

It will return { success: true, message: 'account initialized' } if successfully initialized.

Sponsor Transactions

To make sponsored transactons you can build they required payload and pass it to the sponsoredTxn

const payload: TransactionPayload = {
    function: "0x1::aptos_account::transfer_coins",
    functionArguments: [
      "0xa197f0ffe941bf5cfca7af28438c8692464316fd8075baf6145c26051bc85d4d",
      0,
    ],
    typeArguments: ["0x1::aptos_coin::AptosCoin"],
  };

  const options: TransactionOptions = { gasUnitPrice: 100, maxGasAmount: 2000 };

try {
    const txn = await sdk.sponsoredTxn({
      data: payload,
      options: options
    });
    console.log(txn);
    const txnReceipt = await sdk.aptosClient.waitForTransaction({
      transactionHash: txn.hash,
      options: {
        checkSuccess: true,
      },
    });
    console.log("Txn status", txnReceipt.success);
  } catch (error: any) {
    console.log("error", error);
  }

Sponsor Transaction with Sender Auth and Transaction

  const config = new AptosConfig({ network: Network.MAINNET });
  const aptosClient = new Aptos(config);
  const senderAccount = Account.generate();

  const payload: TransactionPayload = {
    function: "0x1::aptos_account::transfer_coins",
    functionArguments: [
      "0x0b4b8ef78fb296f89006f1936f01427a3a7e0eadd11dd4998c6bf438a0c8ce6b",
      0,
    ],
    typeArguments: ["0x1::aptos_coin::AptosCoin"],
  };
  
  const options: TransactionOptions = { gasUnitPrice: 100, maxGasAmount: 2000 };
  const transaction = await aptosClient.transaction.build.simple({
    sender: senderAccount.accountAddress.toString(),
    data: payload,
    options: options,
    withFeePayer: true,
  });
  const senderAuth = aptosClient.transaction.sign({
    signer: senderAccount,
    transaction: transaction,
  });

  try {
    const txn = await sdk.sponsoredTxnWithSenderAuth({
      transaction: transaction,
      senderAuth: senderAuth,
    });
    console.log(txn);
    const txnReceipt = await sdk.aptosClient.waitForTransaction({
      transactionHash: txn.hash,
      options: {
        checkSuccess: true,
      },
    });
    console.log("Txn status", txnReceipt.success);