|
| 1 | +--- |
| 2 | +description: Send a transaction using Viem. |
| 3 | +--- |
| 4 | + |
| 5 | +import Tabs from '@theme/Tabs'; |
| 6 | +import TabItem from '@theme/TabItem'; |
| 7 | + |
| 8 | +# Use Viem |
| 9 | + |
| 10 | +In this tutorial, you'll send a transaction of 0.001 ETH from one account to another using the [Viem](https://viem.sh/) |
| 11 | +TypeScript library. |
| 12 | + |
| 13 | +Prerequisites |
| 14 | + |
| 15 | +- [Node.js](https://nodejs.org/en/download/) |
| 16 | +- [Install TypeScript](https://www.typescriptlang.org/download/) |
| 17 | +- [Install `ts-node`](https://www.npmjs.com/package/ts-node) |
| 18 | +- An Ethereum account |
| 19 | + |
| 20 | +:::info |
| 21 | +Use [MetaMask](https://metamask.io/) or similar to create an Ethereum account for testing. |
| 22 | +::: |
| 23 | + |
| 24 | +## Steps |
| 25 | + |
| 26 | +### 1. Select your network and verify funds |
| 27 | + |
| 28 | +- **Sepolia** - To use the Sepolia testnet, ensure that your account has Sepolia ETH. |
| 29 | + You can use the [MetaMask faucet](/developer-tools/faucet) to add more funds. |
| 30 | +- **Alternative network** - To use an alternative network, ensure that your account has testnet ETH |
| 31 | + for that network. |
| 32 | + |
| 33 | + :::note |
| 34 | + When using an alternative network, update the chain name in the script (in Step 5) with the |
| 35 | + alternative network name from the [Viem supported chains list](https://github.com/wevm/viem/blob/main/src/chains/index.ts). |
| 36 | + ::: |
| 37 | + |
| 38 | +### 2. Create a project directory |
| 39 | + |
| 40 | +Create a new directory for your project using the command line: |
| 41 | + |
| 42 | +```bash |
| 43 | +mkdir infura |
| 44 | +``` |
| 45 | + |
| 46 | +Change into the new directory: |
| 47 | + |
| 48 | +```bash |
| 49 | +cd infura |
| 50 | +``` |
| 51 | + |
| 52 | +### 3. Install required packages |
| 53 | + |
| 54 | +Install the `viem` package in the project directory. |
| 55 | + |
| 56 | +```bash |
| 57 | +npm i viem |
| 58 | +``` |
| 59 | + |
| 60 | +### 4. Create a `config.ts` file |
| 61 | + |
| 62 | +Create a `config.ts` file in your project directory to store the private key of the sending account: |
| 63 | + |
| 64 | +<Tabs> |
| 65 | + <TabItem value="Syntax" label="Syntax" default> |
| 66 | + |
| 67 | +```tsx title="config.ts" |
| 68 | +import { privateKeyToAccount } from 'viem/accounts' |
| 69 | +export const account = privateKeyToAccount('<PRIVATE-KEY>') |
| 70 | +``` |
| 71 | + </TabItem> |
| 72 | + <TabItem value="Example" label="Example" default> |
| 73 | + |
| 74 | +```tsx title="config.ts" |
| 75 | +import { privateKeyToAccount } from 'viem/accounts' |
| 76 | +export const account = privateKeyToAccount('0x561...x...61df') |
| 77 | +``` |
| 78 | + |
| 79 | + </TabItem> |
| 80 | +</Tabs> |
| 81 | + |
| 82 | +In the `config.ts` file, replace `<PRIVATE-KEY>` with the [private key of your Ethereum account](https://support.metamask.io/configure/accounts/how-to-export-an-accounts-private-key/). |
| 83 | +A transaction must be signed with the sender's private key. Make sure that you prefix the `SIGNER_PRIVATE_KEY` |
| 84 | +value with `0x`. The private key you export from MetaMask isn't prefixed with `0x`. |
| 85 | + |
| 86 | +:::danger |
| 87 | +Never disclose your private key. Anyone with your private keys can steal the assets controlled by those keys. |
| 88 | +::: |
| 89 | + |
| 90 | +### 5. Create a `sendTransaction.ts` file |
| 91 | + |
| 92 | +In the project directory, create a `sendTransaction.ts` file, which configures and sends the transaction. For example: |
| 93 | + |
| 94 | +```tsx |
| 95 | +import { http, createWalletClient, parseEther } from 'viem' |
| 96 | +import { sepolia } from 'viem/chains' |
| 97 | +import { account } from './config' |
| 98 | + |
| 99 | +//create a wallet client to interact with Ethereum accounts |
| 100 | +const walletClient = createWalletClient({ |
| 101 | + chain: sepolia, |
| 102 | + transport: http("https://sepolia.infura.io/v3/API_KEY") |
| 103 | + }) |
| 104 | + |
| 105 | + async function sendTx () { |
| 106 | +//create and send the transaction object |
| 107 | + const hash = await walletClient.sendTransaction({ |
| 108 | + account, |
| 109 | + to: '0xc2CB3fb3924b8DE3A63C1da570a8dBaf2a533eA7', |
| 110 | + value : parseEther ('0.001') |
| 111 | + }) |
| 112 | + |
| 113 | + console.log("Mining transcation... ") |
| 114 | + console.log(`Tx mined in https://sepolia.etherscan.io/tx/${hash}`) |
| 115 | + } |
| 116 | + |
| 117 | +sendTx() |
| 118 | +``` |
| 119 | + |
| 120 | +In the `sendTransaction.ts` file: |
| 121 | + |
| 122 | +- Replace `API_KEY` with your Infura API key. |
| 123 | +- Update the `to` account in the code if you wish to send test ETH to an account of your choice. |
| 124 | + |
| 125 | +### 6. Execute the transaction |
| 126 | + |
| 127 | +To execute the transaction, run: |
| 128 | + |
| 129 | +```bash |
| 130 | +ts-node sendTransaction.ts |
| 131 | +``` |
| 132 | + |
| 133 | +:::note |
| 134 | +`ts-node` is a TypeScript execution engine for Node.js. It allows you to run TypeScript files without |
| 135 | +needing to manually compile them into JavaScript first. |
| 136 | +::: |
| 137 | + |
| 138 | +An alternative way to execute your transaction using node.js is to compile your `sendTransaction.ts` file to JavaScript |
| 139 | +first, and then run the compiled JavaScript file: |
| 140 | + |
| 141 | +```jsx |
| 142 | +tsc sendTransaction.ts |
| 143 | +node sendTransaction.js |
| 144 | +``` |
| 145 | + |
| 146 | +Running the typescript file, `sendTransaction.ts`, directly from your code development environment, like |
| 147 | +Visual Studio Code, works equally well, without the need to use `ts-node` or pre-compiling first to JavaScript. |
| 148 | +Example output: |
| 149 | + |
| 150 | +`Mining transcation... |
| 151 | +Tx mined [https://sepolia.etherscan.io/tx/0x310588719e733118f50c0a1608e13b4e8bd5eb5891d546d89795c2041833abb6](https://sepolia.etherscan.io/tx/0x310588719e733118f50c0a1608e13b4e8bd5eb5891d546d89795c2041833abb6)` |
| 152 | + |
| 153 | +You can search for the transaction on a block explorer such as [Sepolia Etherscan](https://sepolia.etherscan.io/). |
| 154 | + |
| 155 | +### 7. (Optional) Fine tune the transaction details |
| 156 | + |
| 157 | +Viem automatically determines the gas limit and fees. If you want to change the default values, update |
| 158 | +the `sendTransaction` method to include an `estimateGas` result (`gasLimit`) and the `maxFeePerGas` and |
| 159 | +`maxPriorityFeePerGas` parameters. |
| 160 | + |
| 161 | +To do this you will also need to declare an `httpClient` to interface with JSON-RPC methods like `eth_estimateGas`. |
| 162 | + |
| 163 | +Full code overview below: |
| 164 | + |
| 165 | +```tsx |
| 166 | +import { http, createWalletClient, createPublicClient, parseEther, parseGwei } from 'viem' |
| 167 | +import { sepolia } from 'viem/chains' |
| 168 | +import { account } from './config' |
| 169 | + |
| 170 | +//create a wallet client to interact with Ethereum accounts |
| 171 | +const walletClient = createWalletClient({ |
| 172 | + chain: sepolia, |
| 173 | + transport: http("https://sepolia.infura.io/v3/API_KEY") |
| 174 | + }) |
| 175 | + |
| 176 | +//create a public client to interact with JSON-RPC API methods |
| 177 | +const httpClient = createPublicClient({ |
| 178 | + chain: sepolia, |
| 179 | + transport: http("https://sepolia.infura.io/v3/API_KEY"), |
| 180 | + }) |
| 181 | + |
| 182 | + async function sendTx () { |
| 183 | +//estimate gas limit |
| 184 | + const limit = await httpClient.estimateGas({ |
| 185 | + account, |
| 186 | + to: '0xc2CB3fb3924b8DE3A63C1da570a8dBaf2a533eA7', |
| 187 | + value: parseEther('0.001') |
| 188 | + }) |
| 189 | + |
| 190 | +//create and send the transaction object |
| 191 | + const hash = await walletClient.sendTransaction({ |
| 192 | + account, |
| 193 | + to: '0xc2CB3fb3924b8DE3A63C1da570a8dBaf2a533eA7', |
| 194 | + value : parseEther ('0.001'), |
| 195 | + maxFeePerGas: parseGwei('20'), |
| 196 | + maxPriorityFeePerGas: parseGwei ('2'), |
| 197 | + gas: limit, |
| 198 | + }) |
| 199 | + |
| 200 | + console.log("Mining transcation... ") |
| 201 | + console.log(`Tx: https://sepolia.etherscan.io/tx/${hash}`) |
| 202 | + |
| 203 | + } |
| 204 | + |
| 205 | +sendTx() |
| 206 | + |
| 207 | +``` |
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