Across Protocol

Across Protocol is a cross-chain bridge and interoperability layer that lets users move tokens between blockchain networks in seconds. Founded in September 2021 by Risk Labs — the same organization behind UMA Protocol — Across was designed around a core insight: fast, cheap bridging is an economic engineering problem as much as a technical one. Its solution is an intent-based architecture that separates user experience from settlement complexity, letting a competitive relayer network absorb the complexity while users simply specify where they want their funds to end up.

Intent-Based Bridging

The phrase "intents-based" has become common in cross-chain infrastructure, but Across was among the earliest to apply it to bridging at scale. Rather than locking tokens on a source chain and minting wrapped equivalents on the destination — the mechanism behind most first-generation bridges — Across asks users to declare a desired outcome: "I want 100 USDC on Base, starting from Ethereum."

From there, a three-layer system takes over. First, a Request-for-Quote layer solicits competitive offers from a permissionless relayer network. Second, the winning relayer fronts its own capital on the destination chain, delivering the user's funds immediately — no waiting for block finality on the origin chain. Third, the protocol's hub-and-spoke settlement system reimburses relayers approximately every 1.5 hours, bundling all fills into a single aggregated verification step rather than processing each transaction individually.

That aggregation is the efficiency engine. Across uses a HubPool on Ethereum mainnet to hold liquidity provider (LP) capital, connected to SpokePools deployed on each supported chain. A component called the Dataworker batches all relayer fills and proposes them to UMA's Optimistic Oracle for verification. Because settlements are assumed valid and only disputes trigger a UMA token-holder vote, the cost of verification stays roughly constant regardless of how many transactions flow through the system. This hub-and-spoke model means Across scales without proportional increases in settlement cost — one of the structural advantages that helps keep its fees consistently lower than competing bridges.

Scale and Performance

As of mid-2026, Across has processed more than $37 billion in volume across over five million users, with an average fill time of approximately 1.2 seconds from transaction confirmation to funds arriving in the user's wallet. The protocol's security record is notable: no user funds have been lost across that entire volume, a function of the non-custodial architecture where relayers hold capital risk rather than users.

That said, not all incidents have been user-facing. In July 2026, a software exploit in relayer infrastructure drained approximately $4.5 million from relayer wallets. Developers patched the vulnerability within five hours, the exploiter returned a portion of the funds, and user capital remained protected throughout — the incident illustrated both the architecture's security boundaries and the speed of the protocol's response.

Chain Coverage

Across now supports more than 25 networks. The core set covers Ethereum, Arbitrum, Optimism, Base, Polygon, zkSync, Linea, Mode, BNB Smart Chain, Zora, World Chain, Unichain, Ink, Soneium, and Hyperliquid. A V4 architecture update in mid-2025 introduced zero-knowledge proof verification, enabling any generic contract on any destination chain — EVM or non-EVM — to verify a proof without a custom trusted adapter. That change allowed Across to extend bridging support to Solana, one of the few production cross-chain bridges to do so.

ERC-7683 and the Intents Standard

Across and Uniswap Labs jointly developed ERC-7683, a cross-chain intents standard that defines a common interface for expressing and settling cross-chain orders. More than 50 protocols have adopted it, including Base, Arbitrum, Optimism, and Polygon. The Ethereum Foundation's Open Intents Framework, launched in early 2025 with backing from over 30 teams, named Across as a core settler. By positioning the protocol as infrastructure rather than just an application, the ERC-7683 effort broadens Across's role: other protocols can use its settlement layer even when users never directly visit the Across interface.

The Uniswap integration is the most visible example. Uniswap embedded Across bridging natively into its app, covering the majority of its target chains through a single API integration.

Developer Access

Builders can access Across through a public Swap API. A quote request specifies input token, output token, origin chain ID, destination chain ID, and amount. The API returns a filled quote with all necessary transaction data, typically in one call. The same infrastructure supports AI agent use cases: agents can execute cross-chain actions on behalf of users by calling the same API endpoints.

Risk Labs, UMA, and the Security Layer

Risk Labs operates as the foundation entity for both Across and UMA Protocol. UMA's Optimistic Oracle — which uses economic bonds and token-holder dispute resolution rather than a trusted committee — is the cryptoeconomic layer that secures all Across settlements. This design means there is no multisig, no privileged operator, and no single point of failure in the settlement path. Only one honest actor needs to challenge an invalid settlement proposal for the system to reject it.

ACX Token and Governance

Across's native token is ACX, with a fixed total supply of one billion tokens. The distribution allocated 52.5% to the DAO treasury, 25% to strategic partnerships and fundraising (including a token swap for UMA tokens), 12.5% to a user airdrop, and 10% to protocol rewards. ACX is used for governance over protocol parameters and for incentivizing liquidity providers and relayers.

The protocol raised $51 million across two rounds: $10 million in November 2022, and a $41 million round in 2024 led by Paradigm with participation from Bain Capital Crypto, Coinbase Ventures, and Multicoin Capital.

Structural Transition

In mid-2026, Across announced a significant structural change: a conversion from a DAO model to a private U.S. C-corporation, AcrossCo. Token holders were offered the option to exchange ACX for equity in the new entity or to sell at a fixed price. Major exchanges including Binance and Coinbase began winding down ACX trading in the weeks following the announcement. The protocol continues to operate and process transfers; the change affects governance and token mechanics rather than the underlying bridging infrastructure.

Summary

Across Protocol is one of the more technically distinctive bridges in the cross-chain landscape. Its intent-based design, hub-and-spoke settlement, and integration of UMA's Optimistic Oracle address the core tradeoffs of bridge design — speed, cost, and security — in a structurally coherent way. With $37 billion in volume processed, support for 25+ chains including Solana, and a role as co-author of the cross-chain intents standard ERC-7683, it occupies a significant position in the Ethereum and multi-chain ecosystem.