Across Protocol is a cross-chain bridge optimized for speed and capital efficiency, enabling fast asset transfers between Ethereum and its Layer 2 networks including Arbitrum, Optimism, Base, Polygon, zkSync, and Linea. Across uses an intent-based architecture where relayers compete to fill user bridge orders, providing near-instant transfers rather than requiring users to wait for standard bridge finality periods. The protocol is secured by UMA's optimistic oracle for settlement verification. Across is known for having some of the lowest bridge fees and fastest transfer times in the ecosystem, making it popular among users who frequently move assets between Ethereum L2s.