Across is a bridge method using bound relays, a single-sided liquidity pool and UMA's Optimistic Oracle that, when put together, enables decentralized and instantaneous transfers. across's cross-chain bridge allows you to return assets to the main ethereum network L1 in a cheap, secure and fast way.

Across Protocol is now live on mainnet. Across is the fastest, cheapest and most secure L2 to L1 bridge. Any potential Across token will be distributed in the fairest possible way: you decide who gets it, and how it works. We are calling this a “fair fair launch.”

Across has been audited by OpenZeppelin, and in a closed beta has been less expensive and faster than any other solution on the market.

As of today it is possible to bridge USDC, ETH, and UMA from Arbitrum back to L1 Ethereum.

Try Across.to now.

The bridging function works by offering incentives for relayers to offer short-term loans to users on L1, which are repaid after two hours from a liquidity pool on L1. This pool is refilled when the funds arrive from L2 transactions. These transactions are insured by UMA’s Optimistic Oracle.

You can read the details of how all this works in the Across litepaper, docs site, and initial announcement.