Across Protocol vs Hop Protocol: Optimistic Rollup Bridges

introduction

THE ANALYSIS

Introduction: The Battle for Optimistic Rollup Liquidity

A head-to-head comparison of Across Protocol and Hop Protocol, the two dominant bridges for moving assets between Optimistic Rollups like Arbitrum and Optimism.

Across Protocol excels at capital efficiency and low cost because it leverages a single liquidity pool on Ethereum mainnet and a network of off-chain relayers. This model minimizes locked capital and allows for highly competitive fees, often under $1 for standard transfers. For example, its unique architecture has secured over $10B in total volume, demonstrating robust scaling under high demand.

Hop Protocol takes a different approach by deploying canonical bridges and liquidity pools on each connected L2. This results in native asset transfers and deep, chain-specific liquidity, enabling fast, one-click conversions between rollups. The trade-off is higher capital lockup across multiple chains and slightly higher protocol fees to incentivize liquidity providers across its network.

The key trade-off: If your priority is minimizing cost and maximizing capital efficiency for frequent, high-volume transfers, choose Across. If you prioritize user experience with native assets and deep, stable liquidity for a wide array of tokens (including governance tokens), choose Hop.

tldr-summary

Across Protocol vs Hop Protocol

TL;DR: Core Differentiators at a Glance

Key strengths and trade-offs for two leading optimistic rollup bridges.

Across: Best for Cost-Conscious Users

Uses a competitive relayer model: Users pay a fee to a network of relayers who compete for the best rate, often resulting in lower final costs. This is ideal for high-value transfers where saving on fees is a priority, even if speed is variable.

Across: Superior Security & Insurance

Backed by UMA's optimistic oracle: Disputes are resolved by a decentralized oracle network, and a $50M+ insurance fund (backed by Risk Labs) protects users from relayer failure or bridge exploits. This is critical for institutional or protocol treasury transfers.

Hop: Best for Speed & Predictability

Uses bonded liquidity pools (AMMs): Transfers are near-instant (minutes) as they rely on liquidity already on the destination chain. This provides a predictable user experience perfect for DEX traders, arbitrageurs, and general users who prioritize speed.

Hop: Superior Native Token Support

Specializes in canonical asset bridging: Seamlessly moves native assets (e.g., ETH, MATIC) between rollups via its hTokens system. This is the best choice for users who need native assets for DeFi interactions on L2s like Arbitrum, Optimism, and Polygon zkEVM.

HEAD-TO-HEAD COMPARISON

Across Protocol vs Hop Protocol: Architecture, Speed, and Cost

Direct comparison of key metrics and features for optimistic rollup bridge solutions.

Metric	Across Protocol	Hop Protocol
Core Bridging Mechanism	Optimistic Oracle (UMA)	Bonded Messengers (AMMs)
Avg. Bridge Time (Ethereum L1)	~5-15 min	~20-60 min
Avg. Cost (Ethereum L1 to Arbitrum)	$5-15	$10-25
Native Support for Fast Withdrawals
Primary Security Model	Economic (Bonded Relayers)	Economic (Bonder Liquidity)
Supported Rollups	Arbitrum, Optimism, Base	Arbitrum, Optimism, Polygon zkEVM, Base

pros-cons-a

PROS AND CONS ANALYSIS

Key strengths and trade-offs for two leading cross-rollup bridges. Choose based on your primary need: capital efficiency or ecosystem breadth.

Across: Speed & Capital Efficiency

Optimistic validation model: Uses a decentralized network of relayers who front capital, enabling near-instant settlement (often < 2 minutes) without locking funds in a bridge contract. This matters for high-frequency traders and arbitrageurs who need to move large sums quickly without liquidity constraints.

< 2 min

Typical Finality

Across: Cost-Effective for Large Transfers

Single-layer fee model: Users pay only for the destination chain's gas plus a small relayer fee. There is no additional fee for the source chain transaction, as the relayer covers it. This matters for institutional transfers and large DeFi operations where minimizing total cost basis is critical.

Hop: Native Multi-Chain Experience

Wrapped asset (hTokens) with AMMs: Deploys liquidity pools and AMMs on each connected chain (Arbitrum, Optimism, Polygon, etc.), enabling direct swaps between rollup-native assets. This matters for users and dApps that prioritize a seamless, self-custodial experience across a broad ecosystem without relying on third-party relayers.

Hop: Broader Direct Chain Support

Extensive L2 and L1 network: Supports direct bridging between more than 5 major rollups and sidechains without routing through Ethereum L1 for every transfer. This matters for protocols with a multi-chain user base (e.g., NFT platforms, gaming DAOs) that need to connect users across diverse ecosystems like Polygon, Gnosis Chain, and Base.

Direct Chains

Across: Centralized Relayer Risk

Dependency on relayers: Speed relies on a permissioned set of professional relayers (like UMA's Optimistic Oracle) to front capital and attest to transactions. This introduces counterparty and censorship risk, which matters for decentralization-purist protocols that require trust-minimized, permissionless security models.

Hop: Capital Inefficiency & Slippage

Locked liquidity in AMMs: Capital is fragmented across dozens of pools to facilitate swaps, leading to higher opportunity cost for LPs and potential slippage for large transfers. This matters for whales and institutional users moving significant value, where deep, single-sided liquidity (like Across's model) is preferable.

pros-cons-b

Optimistic Rollup Bridge Comparison

Hop Protocol: Pros and Cons

Key strengths and trade-offs between Across and Hop at a glance. Choose based on your protocol's priorities for cost, speed, and security.

Across Protocol: Cost Efficiency

Capital efficiency via UMA's optimistic oracle: Relies on bonded relayers instead of locked liquidity pools, leading to ~50-70% lower fees for large transfers. This matters for high-volume protocols like dYdX or Aave that need to move significant capital between L2s.

~50-70%

Lower Fees

Across Protocol: Security Model

Optimistic security with economic guarantees: Uses UMA's decentralized oracle and a 1-2 hour dispute window. This model is battle-tested, securing $10B+ in cumulative volume. This matters for institutional users and DeFi treasuries prioritizing verifiable security over instant finality.

$10B+

Cumulative Volume

Hop Protocol: Speed & UX

Near-instant guaranteed settlement: Uses bonded relayers and AMM pools to provide users with tokens on the destination chain in ~1-5 minutes. This matters for consumer applications and NFT bridges where user experience and predictable wait times are critical.

~1-5 min

Settlement Time

Hop Protocol: Ecosystem & Liquidity

Deep, established liquidity network: Features native pools on major rollups (Arbitrum, Optimism, Polygon) with $50M+ in TVL. This ensures reliable swaps for high-frequency traders and arbitrageurs who need consistent, deep liquidity for common assets like USDC, ETH, and DAI.

$50M+

TVL

HEAD-TO-HEAD COMPARISON

Cost Analysis: Fees and Capital Efficiency

Direct comparison of bridging costs and capital requirements for Optimistic Rollup solutions.

Metric	Across Protocol	Hop Protocol
Avg. Bridge Fee (ETH Mainnet → Arbitrum)	0.05% - 0.1%	0.04% + ~$5 gas
Capital Efficiency Model	Optimistic Verification (No Lockup)	Liquidity Pool Lockup
Liquidity Provider (LP) Yield Source	Relayer Rewards & Fees	Swap Fees & Incentives
Native Gas Fee Coverage
Typical Bridge Time	~20 min (Challenge Period)	~1-10 min
Supported Rollup Assets	ETH, USDC, WBTC, DAI	ETH, USDC, MATIC, DAI, more

CHOOSE YOUR PRIORITY

User Scenarios: When to Choose Which

Across Protocol for DeFi

Verdict: The go-to for large, time-sensitive, cross-chain capital movements. Strengths: Unbeatable for speed and cost for large transfers. Its optimistic model with bonded relayers provides near-instant confirmation from origin to destination, critical for arbitrage and large liquidity provisioning. The UMA-powered optimistic oracle secures the system, making it ideal for high-value transactions where finality can wait 20 minutes. Supports major DeFi chains like Arbitrum, Optimism, and Base.

Hop Protocol for DeFi

Verdict: Superior for frequent, small-value swaps and composability within its ecosystem. Strengths: Lower fixed costs for small transfers due to its AMM-based liquidity pools. Offers native token bridging (e.g., USDC, DAI) without wrapping, simplifying integration. The Hop Ecosystem (HOP, AMMs) provides yield opportunities for LPs. Better for dApps requiring users to bridge and swap in a single, predictable transaction, though speed is limited by destination chain finality.

verdict

THE ANALYSIS

Verdict: The Strategic Choice for Your Use Case

Choosing between Across and Hop Protocol hinges on your application's tolerance for latency versus its demand for cost efficiency and capital efficiency.

Across Protocol excels at capital efficiency and lower costs because it leverages a single liquidity pool on Ethereum and a network of off-chain relayers. This design minimizes locked capital and reduces fees for users. For example, its primary bridge to Arbitrum often shows finality in under 5 minutes with fees that are a fraction of a traditional AMM bridge, making it ideal for high-value, non-time-sensitive transfers.

Hop Protocol takes a different approach by using a network of canonical bridges and automated market makers (AMMs) on each rollup. This results in faster, native-like withdrawals (often 1-2 minutes) but requires fragmented liquidity pools on each chain, leading to higher capital lockup and potential slippage on large transfers. Its strength is user experience for frequent, smaller cross-rollup swaps.

The key trade-off: If your priority is minimizing operational cost and maximizing capital efficiency for institutional-scale transfers, choose Across. If you prioritize speed and a seamless UX for retail users moving between Optimistic Rollups like Arbitrum and Optimism, choose Hop. For protocol architects, Across is a lean dependency, while Hop offers deeper integration via its hop-node for developers building cross-chain applications.