How to Use a Provider in Ethers.js

What is a Provider in Ethers.js?

A Provider is an abstraction to the Ethereum Network that allows developers to connect to a standard Ethereum node permitting read-only access to the blockchain.

Ethers.js also offers providers for different services each connecting to their respected network. This includes the AlchemyProvider, EtherscanProvider, InfuraProvider, CloudflareProvider, PoketProvider and AnkrProvider - all providing a web API for connecting to the blockchain.

Ethers.js Provider Use Cases

The following consists of potential use cases with Provider within Ethers.js:

Account Methods

• provider.getBalances - retrieve the balances from specific addresses
• provider.getTransactionCount - retrieve the total number of transactions an address has sent

Network Status Methods

• provider.getGasPrice - retrieve the gas price for a transaction that is displayed to a user
• provider.getNetwork - retrieve the network to confirm an user can complete a transaction

Transactions Methods

• provider.call - read from the blockchain and execute smart contracts, but cannot publish to the blockchain.
• provider.getTransaction - retrieve the transaction hash to confirm the completion of an execution by the user.

There are many more use cases that can be explored by visiting the Provider docs, here.

How to Use a Provider with Ethers.js

The following code snippets require prior installation of ethers and alchemy-SDK.

1. Import ethers using Node.js.

const { ethers } = require("ethers");

2. Define network configurations via Mainnet.

const network = "mainnet";

3. Retrieve the API key from Alchemy. For this example, “demo” is used as the API key.

async function blockNum() {
    const provider = new ethers.providers.AlchemyProvider(network, 'demo')
};

4. Define network configurations via Testnet.

async function blockNum() {
...
    const output = await provider.getBlockNumber();
    console.log(output);
};

How to Use a Provider with the Alchemy SDK

The following code snippets require prior installation of the alchemy-SDK.

1. Import alchemy-sdk

import { Alchemy } from 'alchemy-sdk';

2. Optional Config object, but defaults to demo api-key and eth-mainnet.

const settings = {
    apiKey: 'demo', // Replace with your Alchemy API Key.
    network: Network.ETH_MAINNET, // Replace with your network.
};

const alchemy = new Alchemy(settings);

3. Utilize core to refer to all commonly-used Ethers.js Provider methods and Alchemy Enhanced API methods.

// Access standard Ethers.js JSON-RPC node request
alchemy.core.getBlockNumber().then(console.log);

// Access Alchemy Enhanced API requests
alchemy.core.getTokenBalances("0x3f5CE5FBFe3E9af3971dD833D26bA9b5C936f0bE").then(console.log);