Metamask: How to change RPC URL programmatically
As of my last update in April 2023, the official MetaMask API documentation does not allow you to directly change the rpcUrl parameter programmatically. However, it does offer a few ways to do so, which may not be as simple or efficient as expected, but are still viable under certain conditions.
Method 1: Using the Web3.js library and its eth_accounts method
You can use the Web3.js library to get the current accounts from MetaMask’s RPC URL. Then, you can compare them with the desired RPC URL. Here is a simplified example:
async function changeRpcUrl() {
try {
// Get the current account (should be '0x...')
const currentAccount = await Web3.eth.getAccounts();
// Your desired RPC URL
const newRpcUrl = '
// Check if the account is '0x...' and compare it to your RPC URL
if (currentAccount[0] === '0x...') {
console.log('Account matches new RPC URL');
// Update the Web3 instance or network configuration to use the new RPC URL
} else {
console.log('Account does not match new RPC URL');
}
} catch(error) {
console.error(error);
}
}
changeRpcUrl();
Note that changing your web3 instance directly may require manual adjustments to your network configuration.
Method 2: Using MetaMask’s own API endpoint to change the rpcUrl
The official MetaMask API has a method called setRpcUrl that you can use, but like the Web3.js example above, it requires manually updating your account’s RPC URL via this method. However, be aware that there is no direct way to update this via the MetaMask browser interface, as you might expect.
Here’s how to do it:
async function changeRpcUrl() {
try {
// Get the current account (should be '0x...')
const currentAccount = await Web3.eth.getAccounts();
// Your desired RPC URL
const newRpcUrl = '
// Set the rpcUrl parameter programmatically
await provider.setRpcUrl(newRpcUrl, {
// Additional parameters can be set here if needed (e.g. chainId)
});
} catch(error) {
console.error(error);
}
}
changeRpcUrl();
Note on web3 and network configuration
It is recommended to handle the network configuration manually rather than relying on the provided methods, as changes can propagate across multiple chains or networks.
Always keep your web3 instance up to date before updating any RPC URLs.
