Intro
Mantle is a modular layer-2 blockchain built on Ethereum. Our approach to L2 blockchain scaling ensures Ethereum-grade security at impressively low costs. Our testnet is live, allowing developers and users to experiment with an exciting, new tech stack.
This article is intended as a guide for exploring Mantle’s key innovations — to explain how our technology can improve the blockchain experience for users and decentralized applications (dApps). We do assume that the reader has a basic understanding of both Ethereum and optimistic rollups. If you’d like to brush up on core concepts, we recommend reading through our docs or visiting the following links:
Mantle’s technology stack brings unprecedented cost-saving, security, and performance to an Ethereum-based rollup. While we could choose a more traditional framing — such as the blockchain trilemma (scalability, decentralization, and security) — we frame our advancements through this lens because cost, security, and performance are fundamental drivers of blockchain adoption. These axes are essential to onboarding the next billion users and enabling next-generation dApps.
Mantle Technologies
First, we provide a quick overview of Mantle’s core technology improvements.
Modular Design
Though we experience blockchains as a single computing entity, blockchain nodes are actually performing three distinct tasks:
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Nodes maintain a historical ledger of valid transactions
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Nodes participate in consensus to agree on the contents of the ledger
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Nodes update the state of the ledger in response to user or dApp submitted transactions
As each of these tasks grow in complexity, these three functions become entire disciplines in their own right. Today we conceptualize them as: (1) Settlement, (2) Consensus, and (3) Execution. Present-day blockchains, like Solana and Ethereum before The Merge, unify all three “layers” of operation within the same network. This means a node must divide its resources across all tasks at once. For this reason, we call such networks “monolithic blockchains”.
Mantle takes a fundamentally different approach. Rather than having nodes be responsible for several tasks at once, we create a system where every function is performed by an independent network of nodes. This way, each network can specialize in its task, leading to efficiency gains that pass on lower fees to users and better performance for dApps. This is the idea of “modular blockchains”, and can be done without compromising on security.
What is especially unique about Mantle is that it deploys rollup-based scaling with a modular design. This means that Mantle not only benefits from better operational economics through modularity, but also the increased throughput and scale inherent to an optimistic rollup.
Specialized Data Availability
A key challenge to operating an optimistic rollup is maintaining data availability. To uphold fundamental security assumptions, data from the rollup must remain available to give verifiers the opportunity to submit fraud proofs. Data availability is such an essential function that rollups today post their transaction data to Ethereum, incurring expensive gas fees and storage costs.
Here again, Mantle benefits from its modular approach. Rather than posting transaction data to Ethereum, Mantle uses EigenDA, a specialized data availability solution built on top of EigenLayer. EigenDA nodes are specialized to the data availability task and are independently upgradable, introducing lower costs and faster improvement cycles for our network as a whole.
Multi-Party Computation
Another tradeoff for optimistic rollups is the necessity of long wait times for transaction finality. Funds move easily from Ethereum Mainnet to the rollup, but withdrawals require a long challenge period to satisfy trust assumptions. The current standard is a 7-day challenge period, in place on both Optimism and Arbitrum today.
Alternatives include using zero-knowledge proofs to implement a zkProver circuit. This can allow for near-instant finality, but requires complex technology that is still being developed and tested. A more feasible path is to implement architecture and incentive mechanisms that will allow a rollup to lower the challenge period now.
Mantle delivers on exactly this solution. Borrowing from the field of Multi-Party Computation (MPC), Mantle introduces a new node role (MPC node) that affirms the validity of blocks produced by the sequencer. MPC nodes will independently compute state roots from transaction data and provide a signature for valid state transitions. As more nodes sign the block, collective confidence in block validity increases. This creates a viable path for reducing the challenge period to as low as 1-2 days.
Improving the Blockchain Experience
Now with an understanding of Mantle’s design, we can better explain how Mantle users and developers stand to benefit on the axes of cost, security, and performance.
Cost
To explain how Mantle reduces costs for its users, first we must understand where costs originate on an L2.
There are two main sources of cost on a rollup.
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L2 Gas Fees: Just like Ethereum, every operation on a rollup requires a certain amount of gas (see ETH opcodes). Users and dApps pay an execution fee, which is equivalent to the amount of gas used multiplied by the price of gas (determined by network demand).
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L1 Data Publication Fee: All transactions on an optimistic rollup are inevitably published to a data availability layer. Most rollups today publish data to Ethereum, which means the L2 transaction fee must account for Ethereum gas costs.
How does Mantle compare? Being a rollup, Mantle’s gas prices are already incredibly low. This means that the primary cost passed on to users comes from data publication.
This is evident in the network activity of live optimistic rollups, as captured by Kofi’s Rollup Economics dashboard. For existing rollups, data publication costs account for, on average, 73-79% of the total transaction fee. When Ethereum experiences high network activity, this can inflate to more than 90% of total fees.
Data publication is the price a rollup must pay for both data availability and settlement on Ethereum. With Mantle’s modular design, we shift the data availability layer off Ethereum and onto EigenDA. Thereby directly addressing the primary source of cost passed on to users.
*Actual cost models that elaborate on the difference between EigenDA and Ethereum data availability will become available prior to Mantle Mainnet.*
Security
Security is the ability for a blockchain to maintain a valid ledger of transactions. This means individual nodes must discard fraudulent transactions and collectively prevent large-scale censorship from taking place on the network.
Rollups have favorable security properties compared to other scaling solutions, as they inherit security from their base chain. This means that once finality is confirmed, Mantle’s ledger of transactions is as secure as Ethereum.
As Mantle currently operates an optimistic rollup, you must also consider the length of the challenge period. This period of time creates friction for users (who must wait for finality prior to withdrawals) and liquidity providers (who must manage multiple days of liquidity to account for withdrawals).
Mantle MPC nodes offer a roadmap for progressively lowering the challenge period over time. Incentivized by their own staking mechanism, MPC nodes will independently assess and validate the sequencer’s state root. As more MPC signatures are added, confidence in the block’s validity increases.
This is a paradigm shift that takes optimistic rollups from being default optimistic, to verifiably optimistic. MPC signatures create cryptographic evidence to support network optimism. In the extreme, MPC nodes can certify validity under strong probabilistic parameters, removing the tension of proof by contradiction (the existing fraud proof model).
Important to our security model is that Mantle will still use verifiers and fraud proofs along with MPC nodes. We believe that these two mechanisms together — MPC validation and fraud verification — will create lower and upper bounds on Mantle’s challenge period.
*Mantle is currently operating MPC nodes on Mantle Testnet. Information about staking incentives and on how to join the permissionless set of MPC nodes will arrive closer to the mainnet launch.*
Performance
Though there are many ways to assess blockchain performance, nearly all definitions center around the measurement of a blockchain’s latency and throughput.
Latency is the time it takes for an individual transaction to be confirmed by the network. This metric is most important to users, who want to receive confirmation of their transaction in the smallest amount of time. Low latency will unlock use cases in social and gaming, where multi-user interactions are fundamental to the dApp experience.
Throughput is the network’s aggregate rate of processing transactions, often quantified by transactions per second (TPS). High TPS is important to developers, who need certain guarantees about the number of transactions a network can handle. This is especially important for DEXes and marketplace dApps, where multiple transactions can occur in the same block.
Mantle is committed to a throughput of 1,000 transactions per second, benchmarked by the transfer function. Latency for a transaction confirmation on L2 will be 3 seconds, whereas latency for L1 finality will be the length of the challenge period. These metrics apply to our aspirations for mainnet launch, and can be further improved as we continue to developer our network architecture.
Conclusion
These are just some of the many ways Mantle is committed to improving the rollup experience for users. If you’re interested in a deeper dive into any of our network architecture, please take a look at our docs. If you’re interested in building on Mantle, either as a developer or an existing team, you can get in touch by filling out our Interest Form. Our team would be more than happy to speak with you and answer questions on our Developer Telegram or Discord.
Sources:
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https://a16zcrypto.com/why-blockchain-performance-is-hard-to-measure
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https://ethereum-magicians.org/t/a-rollup-centric-ethereum-roadmap/4698
The End