Ethereum: Understanding and Fixing MetaMask RPC Errors
If you are new to building Ethereum-based projects, it is not uncommon to encounter errors when interacting with the Ethereum blockchain. A common error that you may encounter is the MetaMask browser extension “RPC error: method ‘eth_maxPriorityFeePerGas’ does not exist/is not available.”
In this article, we explain what each part of the error message means and provide tips on how to fix it using Hardhat, a popular tool for building Ethereum-based smart contracts.
What is MetaMask?
MetaMask is a browser extension that allows users to interact with the Ethereum blockchain without installing a full node or copying a private key. It provides an easy way to manage Ether and other assets, as well as access various tools and services associated with your Ethereum wallet.
“RPC Error”
RPC stands for Remote Procedure Call, a protocol for executing remote functions in a distributed system. In this case, MetaMask’s RPC endpoint is the Ethereum Virtual Machine (EVM), which allows developers to programmatically interact with the blockchain.
When you use MetaMask in Hardhat or any other application that interacts with the EVM, it typically sends and receives transactions using RPC calls. However, if an error occurs when executing these RPC calls, such as “RPC error: method ‘eth_maxPriorityFeePerGas’ does not exist/is not available,” MetaMask displays this error.
Understanding the eth_maxPriorityFeePerGas Method
The eth_maxPriorityFeePerGas method is used to adjust the priority of a transaction in terms of gas cost. By default, Ethereum transactions have a fixed gas price that determines their priority; higher gas prices result in lower priority.
If you want to optimize the execution time of your smart contract or reduce gas costs, you may need to adjust this method to suit your needs. However, if the “eth_maxPriorityFeePerGas” method is not available, it means that Ethereum has changed its behavior and no longer supports this particular RPC call.
Fixing the Error
To fix the “RPC Error: Method “eth_maxPriorityFeePerGas” does not exist / is not available” message from MetaMask in Hardhat, follow these steps:
- Check your Hardhat configuration: Make sure that the Hardhat configuration file (e.g.
hardhat.config.js) is set up correctly to use the MetaMask RPC endpoint.
- Check your MetaMask version: Make sure that you are using a compatible MetaMask version for your Ethereum blockchain (e.g. Web3.js v1.x).
- Update Hardhat or MetaMask: If you are using an outdated version of Hardhat, update to the latest version and make sure that it supports the Ethereum blockchain.
- Check for conflicts with other RPC endpoints: Check if you are accidentally ignoring another RPC endpoint (e.g.
eth_sendTransaction') using theeth_maxPriorityFeePerGas’ method.
If none of these steps resolve the issue, try updating MetaMask to the latest version or using a different RPC provider, such as MetaMask. For example, Truffle’s built-in RPC endpoint.
Conclusion
In this article, we examined what the MetaMask message “RPC Error: Method `eth_maxPriorityFeePerGas” does not exist / is not available” means in the Hardhat app and how to fix it. By understanding the underlying issues and following these steps, you should be able to fix this error and continue building Ethereum-based smart contracts using MetaMask with Hardhat.