Frontier is the suite that provides an Ethereum compatibility layer for Substrate. It has two components that can be activated separately:

• Pallet EVM: This is the pallet that enables functionality of running EVM contracts. Existing EVM code can be used from there, using addresses and values mapped directly to Substrate.
• Pallet Ethereum with Ethereum compatible RPC methods: The pallet, combined with the RPC module, enables Ethereum block emulation, validates Ethereum-encoded transactions, and allows existing dapps to be deployed on a Substrate blockchain with minimal modifications.

Frontier is not a bridge. Frontier enables you to run Ethereum dapps natively on Substrate, but does not deal with the issues of communicating with other Ethereum-based networks. If you want a standalone blockchain, you are looking for Frontier. If you want to create a parachain that has Ethereum functionality, you need to combine Frontier with Cumulus. If you do not want EVM functionality natively but want to communicate with other networks, you need the Parity Bridge project.

Frontier is still under heavy development. We consider Pallet EVM to be relatively stable, while some parts of Pallet Ethereum's design might still be changed. In the future, using the wrapper block (opens new window) strategy, Frontier can also eventually function as an Ethereum client, allowing you to migrate any eth1.x-based blockchains seamlessly over to Substrate, allowing you to add Substrate-specific features like on-chain governance and forkless upgrades!