Across Protocol is a cross-chain interoperability platform that helps users transfer digital assets between supported blockchain networks through the Across Bridge. Designed for decentralized finance users, it offers a streamlined way to bridge assets and complete cross-chain transactions, with an emphasis on speed, low costs, and non-custodial use.

Across uses an intent-based architecture: users specify the asset and destination they want, while independent relayers compete to fulfill the transfer. Relayers can deliver funds before the protocol completes settlement and repayment, helping reduce the wait associated with some traditional bridging methods. The platform describes its approach as combining fast transfers with optimistic verification and a unified liquidity model.

Across supports networks including Ethereum, Arbitrum, Optimism, Base, and Polygon, with additional ecosystem expansion noted. Its services include bridging assets between chains and swapping and bridging in one step. The protocol also features the ACX token, which is associated with governance, and supports liquidity providers and integrations for builders.