To use the Ethereum API you'll need to create a free Alchemy account first!

What is the Ethereum API?

The Ethereum API allows applications to connect to an Ethereum node that is part of the Ethereum blockchain. Developers can interact with on-chain data and send different types of transactions to the network by utilizing the endpoints provided by the API. The API follows a JSON-RPC standard. JSON-RPC is a stateless, lightweight, remote procedure call (RPC) protocol that is commonly used when interacting with Ethereum.

Getting Started Instructions

1. Choose a Package Manager (npm or yarn)

For this guide, we will be using npm or yarn as our package manager to install necessary packages.

npm

To get started with npm, follow the documentation to install Node.js and npm for your operating system: https://docs.npmjs.com/downloading-and-installing-node-js-and-npm

yarn

To get started with yarn, follow these steps: https://classic.yarnpkg.com/lang/en/docs/install

2. Set Up Your Project

To kickstart your project, open your terminal and execute the following commands:

mkdir ethereum-api-quickstart
cd ethereum-api-quickstart
npm init --yes

mkdir ethereum-api-quickstart
cd ethereum-api-quickstart
yarn init --yes

3. Install Axios

For making API requests, we'll use Axios, a widely-used HTTP client. Install Axios with the following command:

npm install axios

yarn add axios

4. Make Your First Request

You are all set now to use Ethereum API and make your first request. For instance, let's make a request to get the latest block. Create an index.js file in your project directory and paste the following code snippet into the file.

import axios from "axios";

const url = `https://eth-mainnet.g.alchemy.com/v2/${yourAlchemyAPIKey}`;

const payload = {
  jsonrpc: '2.0',
  id: 1,
  method: 'eth_blockNumber',
  params: []
};

axios.post(url, payload)
  .then(response => {
    console.log('The latest block number is', parseInt(response.data.result, 16));
  })
  .catch(error => {
    console.error(error);
  });

Remember to replace yourAlchemyAPIKey with your actual Alchemy API key that you can get from your Alchemy dashboard.

You can also make these requests on testnets like eth-sepolia or eth-holesky by just replacing the request URL:

# Mainnet
https://eth-mainnet.g.alchemy.com/v2/
# Sepolia Testnet
https://eth-sepolia.g.alchemy.com/v2/
# Holesky Testnet
https://eth-holesky.g.alchemy.com/v2/

5. Run Your Script

To execute your script and make a request to the Ethereum network, run:

node index.js

You should see the latest block number outputted to your console.

The latest block number is 11043912

You must not stop here! Want to build your first Dapp and use Ethereum APIs?
Head towards Alchemy Tutorials.