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Quickstart

Explore a basic implementation of account abstraction using ERC-4337. This example will create an account and initiate a transaction on the Ethereum Goerli testnet.

If you are new to account abstraction, we recommend the introduction to account abstraction and an overview of ERC-4337.

1. Download​

Clone the ERC-4337 Examples repository to download the scripts.

git clone https://github.com/stackup-wallet/erc-4337-examples.git

2. Install​

This example uses the Infinitism package created by the ERC-4337 core developers. Install it, and all other dependencies.

yarn install

3. Initialize your configuration​

You can now initialize your local configuration.

yarn run init

A config.json file will be created. The file will look like this:

{
  "bundlerUrl": "http://localhost:4337",
  "rpcUrl": "http://localhost:8545",
  "signingKey": "0x...",
  "entryPoint": "0x...",
  "simpleAccountFactory": "0x...",
  "paymasterUrl": ""
}

If you are not running a local bundler or network node, you will need to set a bundlerUrl and rpcUrl.

You can create a free bundler instance at app.stackup.sh. In this example, select the Ethereum Goerli network for the instance and ensure the version is set to 0.4.0. Once the instance is created, copy the instance URL and replace the default bundlerUrl with the generated address.

Copy the bundler instance URL from the Stackup app

The rpcUrl can be set to any network node. Stackup's bundler also runs a full node, so you can send any normal RPC requests to it as well. In this example we'll set the bundlerUrl and rpcUrl to the same endpoint.

Your config.json fill will now look like this:

{
  "bundlerUrl": "https://node.stackup.sh/v1/rpc/...",
  "rpcUrl": "https://node.stackup.sh/v1/rpc/...",
  "signingKey": "0x...",
  "entryPoint": "0x...",
  "simpleAccountFactory": "0x..."
  "paymasterUrl": ""
}

4. Create an account​

Create an account using the factory simpleAccountFactory defined in the configuration file.

yarn run simpleAccount address

An address will be returned. At this point, the smart contract account has not been deployed.

5. Fund the account​

Deposit ETH into the account on Goerli.

Navigate to a faucet, such as https://goerlifaucet.com/. Enter the account address and claim the testnet ETH.

info

Faucets do not send directly to smart contracts. You must deposit ETH or ERC-20 tokens from the faucet before your first transaction.

6. Initiate the transfer​

The simpleAccount transfer command allows you to transfer MATIC from the smart contract account to any address. It will create a user operation, sign it, and send it to the bundler:

yarn run simpleAccount transfer --to <address> --amount <eth>

You can then find the transaction using a block explorer like etherscan.

With a paymaster​

All commands also have a optional --withPaymaster flag. This will send your user operations to the paymasterUrl specified in your config. If you are using Stackup's paymaster, the paymasterUrl will be the same as the bundlerUrl but at the paymaster endpoint.

For example, if bundlerUrl is:

"bundlerUrl" = "https://node.stackup.sh/v1/rpc/<API key>"

Then your paymasterUrl is:

"paymasterUrl" = "https://app.stackup.sh/api/v2/paymaster/payg/<API key>"

Regardless of whether you use Stackup's paymaster service or not, the endpoint is expected to implement a standard JSON-RPC interface and return back a paymasterAndData field if it agrees to sponsor your transaction.

With this option, you can execute any transaction without needing to hold ETH or MATIC for gas fees.

yarn run simpleAccount transfer --to <address> --amount <eth> --withPaymaster
info

If you are on a Stackup developer plan, you can get quick access to our hosted Paymaster APIs.

Next Steps​

You've successfully sent a transaction using a smart contract account and ERC-4337. Now that you've done a simple transfer with your account, you can also check out other commands in the example, or check out some SDKs compatible with Stackup.

Third Party SDKs​

  • ZeroDev is a smart contract wallet framework that greatly simplifies the implementation of smart contract accounts for wallets and dapps. View their getting started guide to create an example React app.

Examples​