Metamask: A Step-by-Step Guide to Transferring Polygon Tokens to a Smart Contract
As a Polygon (formerly Matic) blockchain developer, you’ve probably encountered issues transferring tokens from your wallet to a smart contract using Metamask. Don’t worry; in this article, we’ll walk you through the process of creating and executing a function that sends Polygon tokens to your contract.
Prerequisites
Before proceeding, make sure you have the following:
- You have a MetaMask wallet set up on your mobile device.
- Your smart contract is implemented on the Polygon blockchain (Polygon.js or Remix).
- The
Subscribe
function is defined in your contract and is accessible outside of the contract.
Step 1: Create a new function
In your contract, create a new function that will take Polygon tokens as input and send them to your wallet:
pragma solidity ^0.8.0;
contract My contract {
// Define token amount and recipient address
uint256 public amount;
public recipient address;
// Function to subscribe to polygon tokens
function subscribe(uint256 amount, recipient address) public {
require(amount > 0, "Amount must be greater than zero");
require(recipient != address(0), "Recipient must be a valid address");
// Transfer tokens to contract wallet
(bool success, ) = payable.transferFrom(msg.sender, address(this), amount);
if (!success) {
console.log("Transfer failed");
}
}
}
Step 2: Define the Subscribe
function
In the MetaMask settings, add a new function with the following properties:
- Name
:
subscribe
- Function name:
.subscribe
- Library:
polygon.js
(or remix)
- Args:
uint256(amount, address(recipient))
The amount
argument should be the token amount you want to send, and the recipient
argument is the address of your contract wallet.
Step 3: Test the function
- Open Metamask on your mobile device.
- Select “Connect” > “Add to MetaMask” or use an existing account.
- In your MetaMask wallet, connect to your Polygon blockchain account (Polygon.js or Remix).
- Go to your contract page and click on the
Subscribe
function.
- Enter a token amount (e.g. 1 Mumbai) and specify the recipient address (your contract wallet).
Expected outcome
After calling the subscribe
function, you should see a success message in the console indicating that the tokens have been transferred to your contract wallet.
By following these steps, you have successfully created a new function to send polygon tokens to your smart contract using Metamask. Don’t forget to update your contract code accordingly to accommodate the new function.
Tips and variations
- To handle errors more robustly, consider adding additional checks or logging mechanisms.
- You can also add input validation for other parameters (e.g.
amount
should be a positive integer).
- For more advanced use cases, you may want to explore using external libraries such as Web3.js or ethers.js to simplify token transactions.