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Alchemy Account Kit

Learn how Lit Programmable Key Pairs can be a signer for Alchemy's Account Kit!


Objectives

At completion of this reading you should be able to:

  • Describe use cases for Account Kit.
  • Understand how to set Lit as a signer to an Account Kit.

What is Account Kit?

Alchemy's Account Kit is a complete toolkit to embed smart accounts in your app with social login, gas abstraction, batch transactions, and more.

Lit Protocol's AA signer is a complete solution for powering AA with a Lit signer.

Powered by account abstraction (ERC-4337), Account Kit provides all the tools you need to onboard users with zero friction:

-aa-sdk: a flexible library to integrate, deploy, and use smart accounts

-Light Account: a gas-optimized ERC-4337 smart contract account

-Signers: integrations with your favorite social login and passkey providers

-Gas Manager APIs: a programmable API to sponsor gas fees in your app‍

-Bundler APIs: the most reliable Bundler to submit UserOps onchain at scale

With Account Kit, you can create a smart account for every user. Smart accounts are smart contract wallets that leverage account abstraction to radically simplify every step of the onboarding experience. Now, a new user can:

  • Create a smart account directly in an Account Kit powered app without third-party - downloads
  • Sign up with an email, social login, passkey, or self-custodial wallet
  • Submit transactions without needing ETH in their account for gas
  • Submit transactions in the background without leaving your app

Guide

Combining Lit PKP wallet with Account Kit allows you to use your Programmable Key Pairs (PKPs) as a smart account for your users.

Pre-requisites

  • Familiarity with JavaScript and TypeScript.
  • Understand the basics of account abstraction.

1. Setup

Install the pkp ethers package:

npm i @lit-protocol/pkp-ethers

Install the LitNodeClient package:

npm i @lit-protocol/lit-node-client
npm i @lit-protocol/crypto
npm i @lit-protocol/auth-helpers

Install the Alchemy AA signer package:

npm i @alchemy/aa-signers

2. Get A Programmable Key Pair (PKP)

Get some tstLPX test tokens from Lit's Chronicle Yellowstone network.

To obtain a PKP, read more within the Lit docs.

To define an Auth Method read about Lit's authentication methods.

For Authentication

3. Create a SmartAccountAuthenticator

Next, setup the LitSigner

import { LitSigner } from "@alchemy/aa-signers";
import { LitAuthMethod } from "@alchemy/aa-signers/lit-protocol";
import { createWalletClient, custom } from "viem";
import { polygonMumbai } from "viem/chains";

const API_KEY = "<YOUR ALCHEMY API KEY>";
const POLYGON_MUMBAI_RPC_URL = `${polygonMumbai.rpcUrls.alchemy.http[0]}/${API_KEY}`;
const PKP_PUBLIC_KEY = "<YOUR PKP PUBLIC KEY>";

const litSigner = new LitSigner<LitAuthMethod>({
pkpPublicKey: PKP_PUBLIC_KEY,
rpcUrl: POLYGON_MUMBAI_RPC_URL,
network: "datil-dev"
});
note

You may pass your own instance of LitNodeClient to LitSigner as inner if not an instance will be created.

4. Use SmartAccountSigner with LightAccount

We can link the SmartAccountSigner to a LightSmartContractAccount from aa-accounts:

import { AlchemyProvider } from "@alchemy/aa-alchemy";
import {
LightSmartContractAccount,
getDefaultLightAccountFactoryAddress,
} from "@alchemy/aa-accounts";
import { polygonMumbai } from "viem/chains";
import { createLitSigner } from "./lit";
const chain = polygonMumbai;

const provider = new AlchemyProvider({
apiKey: "ALCHEMY_API_KEY",
chain,
}).connect(
(rpcClient) =>
new LightSmartContractAccount({
chain,
owner: litSigner,
factoryAddress: getDefaultLightAccountFactoryAddress(chain),
rpcClient,
})
);

5. Authenticating with the Lit Signer

Before the AlchemyProvider can use the LitSigner we must authenticate

To provide authentication context read about Lit's authentication methods.

litSigner.authenticate({
context: "<your auth method or session signatures>"
});

Next Steps

Explore Lit Alchemy AA signer documentation.

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