Simple Web3 Script

Don't know where to start? This guide will walk you through writing a simple web3 script to get the latest block number from the Ethereum mainnet using Alchemy.

This guide assumes you've gone through the getting started steps and have an Alchemy account!​
1. From your command line, create a new project directory and cd into it:
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mkdir web3-example
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cd web3-example
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2. Install the Alchemy Web3 dependency if you have not already:
You can use any web3 library of your choosing, however there are tons of benefits to using Alchemy Web3!
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npm install @alch/alchemy-web3
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3. Create a file named index.js and add the following contents:
You should ultimately replace <api-key> with your Alchemy HTTP API key.
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async function main() {
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 const { createAlchemyWeb3 } = require("@alch/alchemy-web3");
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 const web3 = createAlchemyWeb3("https://eth-mainnet.alchemyapi.io/v2/<api-key>");
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 const blockNumber = await web3.eth.getBlockNumber();
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 console.log("The latest block number is " + blockNumber);
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}
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main();             
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Unfamiliar with the async stuff? Check out this Medium post.
4. Run it using node
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node index.js
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5. You should now see the latest block number output in your console!
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The latest block number is 11043912
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Woo! Congrats! You just wrote your first web3 script using Alchemy 🎉
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Once you complete this tutorial, let us know how your experience was or if you have any feedback by tagging us on Twitter @alchemyplatform!
Not sure what to do next? Build upon your skills learned in this tutorial by checking out our beginner's tutorial for sending Ethereum transactions using Web3 and Alchemy.

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Getting Started

Sending Transactions Using Web3

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Contents

1. From your command line, create a new project directory and cd into it:

2. Install the Alchemy Web3 dependency if you have not already:

3. Create a file named index.js and add the following contents:

4. Run it using node

5. You should now see the latest block number output in your console!

1. From your command line, create a new project directory and `cd` into it:

2. Install the Alchemy Web3 dependency if you have not already:

3. Create a file named `index.js` and add the following contents:

4. Run it using node

5. You should now see the latest block number output in your console!