Arbitrum Bridge vs Across: 2026 Comparison

Direct Layer 2 security: Leverages Arbitrum's underlying rollup security model. Withdrawals are secured by Ethereum's L1 consensus and fraud proofs. This matters for institutional-grade asset transfers where trust minimization is paramount, such as moving large treasury positions or protocol-owned liquidity.

Seamless native asset support: The canonical bridge is the primary minting source for ETH and ERC-20 tokens on Arbitrum One/Nova. This matters for protocols launching natively on Arbitrum (e.g., GMX, Uniswap) that require deep liquidity of the canonical arbETH and official token representations for composability.

Optimistic validation model: Uses a system of bonded relayers and a single optimistic oracle (UMA) for instant liquidity, with fraud resolution after the fact. This matters for user experience and high-frequency operations, enabling sub-2-minute transfers from L2 to L1, crucial for arbitrage bots and responsive treasury management.

Unified liquidity layer: Aggregates liquidity across multiple chains (Arbitrum, Optimism, Base, Polygon) into a single pool, optimizing for cost. This matters for multi-chain DAOs and users bridging frequently between non-Arbitrum chains, as it often provides the lowest fees by routing via the most efficient path, not just the canonical one.

Official canonical bridge secured by the same validators as the Arbitrum L2. This provides maximum security for native ETH and ERC-20 deposits, making it the default choice for protocol treasuries and institutional funds. Transfers are fully composable with Arbitrum's native messaging system.

7-day challenge period for withdrawals to Ethereum L1. This is a security feature but creates significant delay for users needing fast liquidity movement. Best for non-time-sensitive transfers or as a secure settlement layer, not for active trading or quick withdrawals.

~2-4 minute transfers using a validated optimistic model. Relayers provide instant liquidity on the destination chain, with fraud proofs handled by UMA's optimistic oracle. Ideal for high-frequency traders, arbitrageurs, and users prioritizing speed over canonical security.

Relies on a permissioned set of bonded relayers for liquidity and a separate oracle for security. Introduces counterparty risk and potential liquidity fragmentation compared to a native bridge. Requires trust in the Across ecosystem's economic incentives.

Native canonical bridge: Directly secured by the Arbitrum DAO and its underlying rollup security model. This matters for institutional-grade asset transfers where minimizing counterparty risk is paramount. It's the mandatory path for initial ETH deposits to Arbitrum.

Deep ecosystem synergy: Native integration with core Arbitrum infrastructure like the Nitro stack and Stylus. This matters for developers building natively on Arbitrum who require seamless, low-level access for contract-controlled bridging and protocol-owned liquidity management.

Challenge period delay: Standard withdrawals are subject to a 7-day fraud proof window (or ~1 week for AnyTrust chains). This matters for users or applications requiring immediate liquidity on the destination chain, creating a significant UX friction point compared to instant solutions.

Dual gas fee model: Users pay for L1 proof submission and L2 execution. While often subsidized, base costs can be high. This matters for frequent, small-value transfers where competing liquidity network models offer more predictable, often lower effective costs.

~2-4 minute finality: Uses an optimistic verification model with bonded relayers, bypassing L1 challenge periods. This matters for traders and DeFi users who prioritize speed and cannot wait 7 days for funds to become available, enabling near-instant cross-chain actions.

Single-sided liquidity pools: Leverages a unified liquidity layer (UMA's oSnap) on the destination chain, reducing fragmented capital. This matters for liquidity providers seeking higher yields and protocols aiming for deep, sustainable bridge liquidity without massive capital lockup.

Security via relayers and UMA's oracle: Ultimately depends on the economic security of a decentralized relayer network and UMA's optimistic oracle. This matters for risk-averse protocols that prefer the cryptographic guarantees of a native canonical bridge's trust-minimized design.

Multi-contract integration: Requires interacting with Across's spoke pool, hub pool, and adapter contracts. This matters for engineering teams where development simplicity and audit surface are critical, compared to a single, standardized bridge interface.