WTF Solidity Simplified Introduction - Tools Part 4: Alchemy, Blockchain API and Node Infrastructure
I've been relearning Solidity recently, consolidating the details, and writing a "WTF Solidity Simplified Introduction" for beginners to use. I update it with 1-3 lessons every week.
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Alchemy is a super node that provides the most widely used blockchain API for Ethereum, Polygon, Solana, Arbitrum, Optimism, Flow, and Crypto.org. It offers all the features of a node, including JSON-RPC support, but with the reliability, data accuracy, and scalability required to run world-class applications on the blockchain.
Dapp applications developed on Ethereum (off-chain) need to interact with the blockchain (on-chain). In the early days, there was limited infrastructure on Ethereum, and developers had to deploy a local Ethereum node to complete off-chain and on-chain interactions, which was very cumbersome and time-consuming.
Alchemy and Infura have built a bridge between off-chain and on-chain interactions, making it easier for developers. They provide users with instant and scalable API access to the Ethereum and IPFS networks. After registering on the Alchemy and Infura websites, developers can apply for a free Ethereum API key, which allows them to interact with the blockchain using their nodes. In addition, the MetaMask wallet has built-in Infura services, making it easy for users to access the Ethereum network.
For an introduction to Infura, you can refer to WTF Solidity Simplified Introduction - Tools Part 2: Infura, Connecting Off-Chain and On-Chain
The left side is Alchemy, and the right side is Infura. Let's compare their free plans.
Alchemy has no daily usage limit, while Infura has a daily limit of 100,000 requests.
Alchemy has a monthly usage limit of 300,000,000 requests, while Infura has a monthly limit of 3,000,000 requests.
Alchemy supports: ETH, Polygon, Solana, Arbitrum, Optimism.
Infura supports: ETH, ETH2, IPFS, Filecoin.
Alchemy has its own set of enhanced web3 APIs. You can refer to the documentation for more details.
Website: alchemy.com
After registering, go to the Dashboard and click the + CREATE APP button in the top right corner.
CHAIN: Select the network you need. For Ethereum, it would be Ethereum.
NETWORK: Choose whether it's the mainnet or a testnet.
After filling in the information, click CREATE APP to create the API Key.
Go back to the Dashboard, and you will see that the API Key named WTFSolidity has been created. In the Dashboard, click the view key button to view the details of the API Key.
You can see that we have created the corresponding API Key, and both HTTPS and WebSockets are supported.
In ethers.js, we can use the Alchemy API Key to create a JsonRpcProvider for interacting with the blockchain.
const { ethers } = require("ethers");
// Replace with your Alchemy API Key
const ALCHEMY_ID = ''
const provider = new ethers.providers.JsonRpcProvider(`https://eth-mainnet.g.alchemy.com/v2/${ALCHEMY_ID}`)Go to the Settings page in the MetaMask wallet and click on Networks. Click on Add Network to add the Alchemy ETH chain to MetaMask using the following parameters:
Network Name: Alchemy-eth
RPC URL: Fill in the Alchemy RPC URL you obtained
Chain ID: 1
Currency Symbol: ETH
Block Explorer URL: https://etherscan.io
In this lesson, we introduced how to create and use an Alchemy API Key to conveniently access the Ethereum blockchain.