Bridging basics

Although Optimism is an L2 (and therefore fundamentally connected to Ethereum), it's also a separate blockchain system. App developers commonly need to move data and assets between Optimism and Ethereum. We call the process of moving data and assets between the two networks "bridging".

Sending tokens

For the most common usecase, moving tokens around, we've created the Standard Token Bridge. The Standard Token Bridge is a simple smart contract with all the functionality you need to move tokens between Optimism and Ethereum. It also allows you to easily create L2 representations of existing tokens on Ethereum.

Sending data

If the Standard Token Bridge doesn't fully cover your usecase, you can also send arbitrary data between L1 and L2. You can use this functionality to have a contract on Ethereum trigger a contract function on Optimism and vice versa. We've made this process as easy as possible by giving developers a simple API for triggering a cross-chain function call. We even use this API under the hood (opens new window) inside the Standard Token Bridge.