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How to Send Tokens Using Ethers.js


Ethers.js is a great javascript library for interacting with the Ethereum blockchain.

One of the more useful things it can do is interact with ERC-20 Smart Contracts, aka Tokens.

Here's the code:

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

const provider = new ethers.providers.JsonRpcProvider(RPC_URL);
const signer = provider.getSigner();

let wallet = new ethers.Wallet(PRIVKEY);
wallet = wallet.connect(provider);
let token = new ethers.Contract(CONTRACT_ADDR, ABI, wallet);

token.transfer(ADDR, ethers.utils.parseUnits(AMOUNT, DECIMALS));

Now, let's go over it line by line.

The first line imports the module. Nothing interesting here.

The next line, const provider = new ethers.providers.JsonRpcProvider(RPC_URL); creates a provider based on the RPC url given. Essentially, the RPC url is connected to a node that will act as your gateway to the network.

A list of some RPC urls:

The third line defines signer. A signer is the eth acccount, which can sign transactions or messages.

The fourth line creates a wallet from the private key

Warning: Do not store your private key in plain text (use environmental variables) or share it with anyone, as anyone with the private key can steal your funds

Then, the wallet and the provider are linked.

The second to last line (let token = new ethers.Contract(CONTRACT_ADDR, ABI, wallet);) gets the token by its contract address and ABI (Application Binary Interface). ERC-20 Contracts all should have more or less the same ABI, so you can usually just copy the one linked here. However, if it doesn't, you can usually find the ABI for verified contracts on etherscan.

The last line is the one that actually sends the tokens. ADDR is the address to send to, and AMOUNT is the amount in whole coins, which then is converted into raw. The DECIMAL field is usually 18, but that depends on the number of decimals the token you are sending has. Additionally, you can override the default gas fees by adding {gasPrice: GAS PRICE HERE, gasLimit: GAS LIMIT HERE} as a parameter at the end, like so:

token.transfer(ADDR, ethers.utils.parseUnits(AMOUNT, DECIMALS), {gasPrice: GAS PRICE HERE, gasLimit: GAS LIMIT HERE});
Warning: Please be careful with gas fees