### Picking an EntryPoint [#picking-an-entrypoint]
Currently there are two versions of ERC-4337 that are used in production. They are referred to as "EntryPoint 0.6" and "EntryPoint 0.7", where "EntryPoint" refers to the singleton ERC-4337 contract.
If you are building a new application, we recommend using EntryPoint 0.7 (Kernel v3), which gives you the latest and greatest features and optimizations. If you already have an application using EntryPoint 0.6 (Kernel v2), just stick with it -- it will be supported indefinitely.
In this tutorial, we will use EntryPoint 0.7. Start by selecting an EntryPoint:
```ts
const entryPoint = getEntryPoint("0.7")
```
### Picking a Kernel version [#picking-a-kernel-version]
[Kernel](https://github.com/zerodevapp/kernel) is the smart account that ZeroDev builds on. ZeroDev SDK used to implicitly use the latest version of Kernel, which has caused some compatibility issues when people upgrade the SDK. Therefore, starting from ZeroDev SDK v5.3, we require that you explicitly specify the Kernel version. This is how you generally should choose:
* If you had already been in production with ZeroDev SDK v4 or lower, use Kernel version 2.4 with EntryPoint 0.6.
* If you had already been in production with ZeroDev SDK v5, use Kernel version 3.0 with EntryPoint 0.7.
* If you are still in development or starting a new project, use Kernel version 3.1 with EntryPoint 0.7.
```ts
import { KERNEL_V3_1 } from "@zerodev/sdk/constants"
const kernelVersion = KERNEL_V3_1
```
### Creating a public client [#creating-a-public-client]
In Viem, a [public client](https://viem.sh/docs/clients/public.html) is an interface to a JSON-RPC API such as Infura or Alchemy.
```typescript
import { createPublicClient, http } from "viem"
import { base } from 'viem/chains'
const publicClient = createPublicClient({
// In production, you will want to set your RPC provider here (e.g. Infura/Alchemy).
transport: http(),
chain: base,
})
```
### Creating a signer [#creating-a-signer]
As aforementioned, a Kernel account using a ECDSA validator is "owned" by a signer, which is anything that can sign messages with a private key.
Since Kernel is built on top of Viem, we can use any [Viem account](https://viem.sh/docs/accounts/local/toAccount) as the signer. In this example, we create a signer from a private key:
```typescript
import { Hex } from "viem"
import { privateKeyToAccount } from "viem/accounts"
const signer = privateKeyToAccount("PRIVATE_KEY" as Hex)
```
Replace `PRIVATE_KEY` with an actual private key. You can [generate a random one here](https://privatekeys.pw/keys/ethereum/random).
### Creating a ECDSA validator [#creating-a-ecdsa-validator]
Then create a ECDSA validator from the signer:
```typescript
import { signerToEcdsaValidator } from "@zerodev/ecdsa-validator"
const ecdsaValidator = await signerToEcdsaValidator(publicClient, {
signer,
entryPoint,
kernelVersion
})
```
### Create a Kernel account [#create-a-kernel-account]
Next, create a Kernel account with the ECDSA validator:
```typescript
import { createKernelAccount } from "@zerodev/sdk"
const account = await createKernelAccount(publicClient, {
plugins: {
sudo: ecdsaValidator,
},
entryPoint,
kernelVersion
})
```
### Create an account client [#create-an-account-client]
Now that we have an account, we can finally construct an "account client," which is the equivalent of a [wallet client in Viem](https://viem.sh/docs/clients/wallet.html) that allows you to send UserOps to bundlers.
```typescript
import { createKernelAccountClient } from "@zerodev/sdk"
import { http } from "viem"
import { base } from 'viem/chains'
const kernelClient = createKernelAccountClient({
account,
// Replace with your chain
chain: base,
// Find the RPC in your ZeroDev dashboard
bundlerTransport: http('ZERODEV_RPC'),
// Required - the public client
client: publicClient,
// Optional -- only if you want to use a paymaster
paymaster: {
getPaymasterData(userOperation) {
return paymasterClient.sponsorUserOperation({userOperation})
}
},
})
```
Note that:
* You need to replace the `ZERODEV_RPC` with the RPC found on your ZeroDev dashboard.
* You need to make sure to set the right `chain`.
* `paymaster` only needs to be specified if you want to [use a paymaster](/smart-accounts/sponsor-gas/evm).
Now you are ready to do things with your smart account, like [sending UserOps](/smart-accounts/send-transactions)!
## FAQs [#faqs]