The rapid evolution of decentralized finance (DeFi) has made cross-chain interoperability a critical necessity. As users interact with multiple Layer 2 solutions and rollups, the need for secure, efficient, and capital-effective bridges has never been greater. Enter Across Protocol — a next-generation cross-chain bridge designed to streamline asset transfers between Ethereum and other EVM-compatible blockchains.
Built on UMA’s optimistic oracle technology, Across Protocol offers a secure, decentralized, and highly efficient infrastructure for moving assets across chains. This article explores how Across works, its core features, tokenomics, and why it stands out in the crowded cross-chain ecosystem.
Understanding Across Protocol
Across Protocol is a decentralized cross-chain messaging and asset bridging platform that connects Ethereum with various Layer 2 networks and rollups. Its primary goal is to enable fast, low-cost, and secure transfers of tokens while maintaining high capital efficiency.
Unlike traditional bridges that lock liquidity on multiple chains, Across uses a single liquidity pool anchored on Ethereum mainnet. This design reduces capital fragmentation, enhances security, and lowers costs for end users. By leveraging third-party relayers and an optimistic verification mechanism, Across ensures rapid transaction finality without compromising decentralization.
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Core Features of Across Protocol
Capital Efficiency Through a Single Liquidity Pool
One of Across’s most innovative features is its unified liquidity model. Instead of spreading liquidity across multiple chains, the majority of funds remain secured on Ethereum. When a user initiates a transfer from a Layer 2 to Ethereum (or vice versa), a relayer fulfills the request using funds from the central pool.
This approach significantly improves capital utilization. Liquidity providers (LPs) earn yield based on the overall usage of the pool, rather than being tied to individual chain pairs. The fee model is driven by dynamic interest rates tied to demand, offering predictable pricing and reduced slippage.
Permissionless Relayer Network
Across employs a competitive ecosystem of independent relayers who front funds to fulfill cross-chain deposit requests. These relayers operate in a permissionless environment, meaning anyone can participate by staking collateral and running bot infrastructure.
Relayers are incentivized to act honestly — if they provide incorrect proofs or fail to deliver assets, their collateral can be slashed via dispute resolution. This creates a trust-minimized environment where speed and reliability are enforced through economic incentives.
Optimistic Oracle Security with UMA
Security is paramount in cross-chain bridging. Across leverages UMA’s optimistic oracle to validate the correctness of cross-chain messages. Under this model, transactions are assumed valid unless challenged within a dispute period.
If a malicious relayer submits fraudulent data, any network participant can initiate a dispute. UMA token holders then vote on the correct outcome. Crucially, only one honest actor needs to detect fraud for the system to remain secure — a principle known as cryptoeconomic security.
This design eliminates the need for trusted validators while maintaining robust security guarantees.
Universal Bridge Adapter (UBA)
A major upgrade to Across is the introduction of the Universal Bridge Adapter (UBA), which dramatically expands interoperability. UBA enables connections between any EVM-compatible chains using an incentivized rebalancing mechanism.
By abstracting away chain-specific complexities, UBA allows Across to support new networks quickly and efficiently. It also rewards users who help maintain optimal liquidity distribution across chains, further aligning incentives within the ecosystem.
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ACX Token: Governance and Incentives
The ACX token is the native ERC-20 utility token of Across Protocol, serving three primary functions: governance, incentives, and ecosystem growth.
Decentralized Governance
ACX holders govern the protocol through a decentralized autonomous organization (DAO). Using platforms like Snapshot and Forum, stakeholders can propose, discuss, and vote on changes to protocol parameters, treasury allocations, and upgrades.
Governance is fully decentralized, with no central authority controlling decision-making. This ensures long-term alignment between developers, users, and liquidity providers.
Incentive Mechanisms
ACX is used to reward participation across multiple vectors:
- Liquidity Providers (LPs): Earn ACX emissions through the Reward Locking Program, which boosts yields for those providing sustained liquidity.
- Referral Program: Users who invite others to use Across can earn ACX rewards based on referred volume.
- Early Supporters: A significant portion of the token supply was allocated to early bridge users, liquidity providers, and participants in the Bridge Traveler program.
These mechanisms encourage active participation and long-term commitment to the protocol’s success.
Token Distribution Overview
The total supply of ACX is capped at 1 billion tokens, distributed as follows:
- Airdrop (115 million): Rewarded to early adopters, including community members, bridge users before July 2022, liquidity providers, and Bridge Traveler participants.
- Strategic Partnerships & Fundraise (250 million): Includes a token swap with UMA’s Risk Labs foundation and funds raised from investors like Hack VC and Placeholder.
- Protocol Rewards (100 million): Allocated for referral incentives and LP reward locking programs.
- Across DAO Treasury Reserve (535 million): Held for future development, grants, partnerships, and ecosystem initiatives.
This distribution emphasizes decentralization, community ownership, and sustainable growth.
Strategic Partnerships
Across Protocol has formed key collaborations that strengthen its technological foundation and expand its reach:
- UMA: Provides the optimistic oracle infrastructure essential for secure dispute resolution.
- Snapshot: Enables gas-efficient, off-chain voting for DAO governance.
- Risk Labs Foundation: Works alongside the Across DAO to refine bridge architecture and promote adoption.
These partnerships enhance both security and governance maturity, positioning Across as a reliable player in the DeFi space.
Frequently Asked Questions (FAQ)
Q: What makes Across Protocol different from other cross-chain bridges?
A: Across stands out due to its single liquidity pool model, optimistic oracle security via UMA, and permissionless relayer network. These features combine capital efficiency, low fees, and strong decentralization — a rare balance in today’s bridge landscape.
Q: How do I become a relayer on Across?
A: Anyone can become a relayer by running bot infrastructure and posting collateral. Relayers earn fees for fulfilling user deposits quickly and accurately. Technical documentation is available in the public repository.
Q: Is my资金 safe when using Across?
A: Yes. Most funds stay on Ethereum mainnet, reducing exposure to less-secure chains. Fraudulent activity is detected via UMA’s optimistic oracle, ensuring that only valid transactions settle.
Q: Can I earn ACX tokens without providing liquidity?
A: Yes. You can participate in the referral program or be eligible for future incentive campaigns. Additionally, holding ACX allows you to vote in governance and influence protocol direction.
Q: Which chains does Across support?
A: Across supports major EVM-compatible Layer 2s such as Arbitrum, Optimism, Base, zkSync Era, and others — with more being added through the Universal Bridge Adapter.
Q: How does the interest rate fee model work?
A: Fees are dynamically adjusted based on demand for bridging services. High utilization increases fees slightly, which are then redistributed to LPs — creating a self-sustaining economic loop.
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Final Thoughts
Across Protocol represents a significant advancement in cross-chain infrastructure. By combining capital efficiency, cryptoeconomic security, and community-driven governance, it addresses many of the shortcomings seen in earlier bridge designs.
As multi-chain DeFi continues to grow, solutions like Across will play a vital role in connecting ecosystems securely and efficiently. Whether you're a user looking for low-cost transfers or a participant interested in governance and rewards, Across offers a compelling value proposition powered by innovation and decentralization.
With ongoing development, expanding chain support via UBA, and strong community engagement, Across Protocol is well-positioned to become a cornerstone of the interconnected blockchain future.