Metamask: Problem – Unable to deploy to Polygon Mumbai network with dedicated RPC URL
For me, as a blockchain developer, the deployment of smart contracts and decentralized applications (dApps) is an important step in the development process. However, problems may occur when deploying to the Polygon Mumbai network due to connectivity issues or configuration errors.
In this article, we’ll look at an issue reported by several users who are having trouble deploying their Metamask-based contracts on the Polygon Mumbai network using a dedicated RPC (remote procedure call) URL from Infura.
Problem:
After setting up the necessary infrastructure and setting up the RPC URL, the developers ran into problems when trying to deploy their contracts. In particular:
- Deployment failed: The contract was not deployed as expected, even after requesting to interact with it via the MetaMask interface.
- RPC Connection Error: The user encountered a connection error while connecting to the Polygon Mumbai network.
Solution:
To resolve these issues and successfully deploy contracts on the Polygon Mumbai network using Metamask, follow these steps:
Step 1: Update the Infura URL
Before attempting to deploy the contract, update the INFURA_URL environment variable in your project to point to the correct RPC endpoint for the Polygon Mumbai network.
export INFURA_URL="
Replace YOUR_PROJECT_ID with your current Infura project ID.
Step 2: Check the connection
Verify that you can successfully connect to the RPC endpoint using MetaMask. This can be done by creating a new wallet and checking if it is connected to your Ethereum account.
npx polygon-cli connect --rpcurl --etherscan apiKey=YOUR_ETHERSCAN_API_KEY
Replace YOUR_PROJECT_ID with your actual Infura project ID and YOUR_ETHERSCAN_API_KEY with your EthereumSCAN API key.
Step 3: Configure RPC settings
If you’re having trouble connecting to the Polygon Mumbai network, try configuring the RPC settings using the rpc_url' argument in your contract's deployment script. The following example demonstrates how to configure therpc_urlparameter:
import { deploy } from 'ethers';
const provider = new ethers.providers.InfuraProvider(' {
network: 'mumbai',
rpcUrls: {
mainnet: '
test: '
},
});
export async function deployContract() {
const contractAddress = '0x...';
// Determine the ABI of your contract
const abi = [...];
try {
const tx = await deploy(contractAddress, provider, { abi });
console.log(tx);
} catch (error) {
console.error(error);
}
}
Replace YOUR_PROJECT_IDwith your actual Infura project ID andcontractAddresswith your contract address.
Step 4: Update the RPC URL in Metamask
After updating theINFURA_URLenvironment variable, update the RPC URL in your MetaMask interface to point to the correct endpoint for the Polygon Mumbai network. You can do this by creating a new wallet and verifying that it is connected to your Ethereum account.
npx polygon-cli connect --rpcurl --etherscan apiKey=YOUR_ETHERSCAN_API_KEY
Replace YOUR_PROJECT_IDwith your actual Infura project ID andYOUR_ETHERSCAN_API_KEY` with your EthereumSCAN API key.
###Additional tips
- Make sure you have the latest version of Metamask for Polygon Mumbai installed and configured.