Background

Layer2 has been the recent focal point in the market.

ZK-based Rollups have interestingly launched their own ZKEVM and testnets, anticipating capturing real users and funds through airdrops. As a result, users looking to take advantage of these opportunities found themselves interacting with numerous Layer2 chains daily. However, this also underscores the intense competition in this arena. In particular, Arbitrum gained significant attention by leveraging airdrops and subsequently provided ecosystem grants to its projects, encouraging ecosystem growth and user incentives. This strategy has kept Arbitrum’s Total Value Locked (TVL) and transactions consistently over twice that of Optimism. Meanwhile, ZKSync achieved rapid growth in TVL and transactions through eras and anticipated airdrops.

While facing these challenges in terms of data, the earliest token issuer, Optimism, also grappled with significant token unlocks every month. In an attempt to turn things around, Optimism retaliated with its OP Stack strategy. The initial launch of OP Stack didn’t garner much attention until Coinbase announced its plans to use OP Stack to develop its own Layer2BASE, and A16Z revealed its intention to use OP Stack to issue its Layer2 Magi. Following this, launching a Layer2 seemed to gain consensus as projects from various sectors announced their entry into the Layer2 War. The price of the OP token surged, culminating with the launch of the BASE chain.

Other established Layer2 solutions couldn’t remain on the sidelines either, choosing to release their own stacks to compete with Optimism, such as Arbitrum Orbit, Polygon 2.0, ZKSync’s Hyperchain, and Starware’s Starknet.

Layer2 Achieves Milestone Success

The market holds varied perspectives on whether the future of blockchain lies in multi-chains or Layer2. Currently, both Layer2 and multi-chains (especially functional chains) have witnessed notable advancements. At the start of 2022, there was an ongoing debate about whether the future of blockchain was about multi-chains or ETH combined with Layer2. Now, Cosmos seems to have taken a backseat, overtaken in prominence by Layer2 solutions such as Optimism, Arbitrum, Polygon, and ZKSync. Funds and developers have effectively cast their votes, overwhelmingly choosing to invest and settle within the Layer2 ecosystem.

Post its shift to POS and the Shanghai upgrade, Ethereum (ETH) now carries the majority of on-chain assets, and it continues to lead the race in scalability and deflation. Instead of creating a new public chain with no innovation, and building a new ecosystem to compete for Ethereum’s traffic, it’s more efficient to rely on Ethereum’s computational power and state for security. Using ETH as the GAS Token and drawing developers and liquidity through the Ethereum Virtual Machine (EVM) and incentives allows for value migration, creating a flywheel effect. Data indicates that, in terms of Total Value Locked (TVL), project count, and unique user numbers, Layer2 holds the upper hand. Moreover, many projects have announced their intentions to release Layer2 solutions, signifying the dawn of the multi-chain era for Layer2.

However, in the wake of the Terra incident, chains like Terra and Juno from the Cosmos ecosystem seemed to almost exit the market. Yet, entities within the Cosmos ecosystem like Injective, Canto, Berachain, Sei, and DYDX v4 are either about to launch or have already rolled out their mainnets. They aim to tackle the current blockchain challenges in more aggressive ways and establish their own ecosystems. Cosmos has also introduced Evmos to tap into Ethereum’s momentum, draining Ethereum’s liquidity. Additionally, Cosmos released Cosmos 2.0, aiming to empower ATOM by ensuring inter-chain security and block auctions, thereby enhancing its ecosystem’s significance. Yet, judging by the current secondary market trends and TVL, the Cosmos ecosystem hasn’t managed to recover from its slump post-Terra, partly due to its fragmented internal approach.

Source: L2BEAT – The state of the layer two ecosystem, defillama.com, as of August 21, 2023.

OP Stack

Replicating Cosmos’ Strategy

The Layer2 multi-chain era closely mirrors the multi-chain narratives once touted by Cosmos and Polkadot. However, the key difference is that instead of Cosmos hub or relay chains linking the multiple chains, it is Ethereum that stands central. In truth, Ethereum solely offers security at the DA layer without genuinely interconnecting the Layer2s. This scenario presents an opportunity for Stack. As a middle Rollup layer, Layer2 can not only provide customized blockchain development services for revenue but also act as a hub to capture the value of other Layer2 chains or charge Layer3 from the DA layer.

Indeed, Layer2 is essentially a modular step within Ethereum. By stacking modularized Layer2s, one can efficiently construct a Layer2 system. This system, when connected through a central hub, can achieve atomic cross-chain operations. Building on this foundation, the central hub can also operate at the DA layer, and Layer3 application chains can be established on top, unleashing the innovative potential of public blockchains.

By turning core features into universal components, akin to what Cosmos did, and then offering them to other chains, one can establish its own ecosystem. Such a competitive edge is unparalleled by independently establishing a single blockchain. Optimism has chosen a strategy similar to Cosmos: offering low-barrier development, permissionless chain launches, high compatibility, and cross-chain operability to create its ecosystem.

The Dawn of Multi-Chain Narratives: Cosmos

Cosmos encourages collaborative efforts among various blockchain networks. By sharing value and data, it fosters interconnectivity within the ecosystem and is among the pioneering players in exploring multi-chain interoperability. Cosmos is a highly modular and interoperable blockchain ecosystem, comprising three core components: the Tendermint consensus mechanism, the Cosmos SDK, and the IBC (Inter-Blockchain Communication) cross-chain communication protocol.

1.Tendermint Consensus Mechanism

Tendermint serves as the network consensus engine for Cosmos Hub and consists of two main parts: Tendermint Core and ABCI. It utilizes a hybrid consensus of PBFT+Bonded PoS, ensuring that over 2/3 of the validators reach consensus. Tendermint separates blockchain applications from the underlying consensus, controlling application logic via a state machine while providing an ABCI interface for application layer interaction. This architecture supports both consensus and integration with other chains.

Source: Tendermint Architecture: Official diagram

2.Cosmos SDK

The Cosmos SDK is a toolkit for developers, enabling the construction of modular state machines on top of Tendermint. Developers can use the SDK to create new blockchains or bridge into Cosmos using Peg Zones. The SDK introduces the concept of multi-store, dividing the application state into different isolated zones, with each module managing its own state. Primary modules of the SDK include Bank, Auth, and Staking & Slashing, all aimed at building sophisticated state machines.

Source: Cosmos SDK Diagram: Official diagram

3.IBC Cross-Chain Communication Protocol

IBC is the protocol in Cosmos that facilitates communication between different blockchains, enabling cross-chain interactions among Zones. By establishing IBC connections on the Hub, a Zone can communicate with other Zones connected to the same Hub. Through IBC, Zones can transmit tokens and data packets, achieving the transfer of cross-chain assets and information. The PG Zone serves as a bridge, connecting external blockchains (e.g., Bitcoin) that cannot directly integrate via IBC, making them interoperable with chains within Cosmos.

Source: IBC Communication Diagram: Official diagram

The combination of these components allows developers to craft secure and flexible applications, realizing cross-chain communication and asset transfers between blockchains.

Cosmos’ Hub and Zone Architecture and Cross-chain Interoperability

Cosmos utilizes a Hub and Zone architectural model. In this structure, the Hub serves as the central nexus of the network, while Zones are individual public chains that connect independently. The Hub monitors and records the status of each Zone. In turn, each Zone reports its newly generated blocks to the Hub and synchronizes with the Hub’s state. Instead of directly synchronizing with one another, different Zones communicate indirectly by sending data packets to the Hub.

Technically, the Hub and Zone model of Cosmos achieves interoperability between different blockchains. Zones communicate through the Hub, which synchronizes the global state in real-time. By separating blockchain applications from the underlying consensus mechanism and providing an ABCI interface for interaction with the application layer, developers can write application logic in any language. This structure not only facilitates consensus but also simplifies the integration of other blockchains.

Within the Cosmos ecosystem, the core token $ATOM is primarily used for transaction fees and governance voting. The demand for this token is directly tied to the development of the Cosmos ecosystem. Cosmos aims to establish a universal blockchain development framework and address cross-chain issues, fulfilling the vision of a multi-chain universe.

Regarding its cross-chain mechanism, the Cosmos Hub acts as a relay chain, while Zones operate as parallel chains, each with its validators. Serving as the heart of the network, the Cosmos Hub allows different blockchains to connect via the IBC protocol. Zones communicate with other Zones through the Hub, and each Zone is managed in a decentralized manner. Consequently, if a particular Zone faces an attack or malicious behavior, other Zones remain unaffected.

Cosmos Architecture Overview: Image sourced from the official site

Overall, Cosmos has played a pioneering role in the domain of multi-chain interoperability. Through its Hub and Zone architecture, along with the introduction of the IBC protocol, it has facilitated seamless communication and cross-chain asset transfers between various blockchains. Additionally, Cosmos’ modular structure offers developers a high degree of flexibility. With the Cosmos SDK, developers can create customized blockchain applications featuring a variety of functional modules. At the same time, the Tendermint consensus mechanism plays a pivotal role within Cosmos. It employs a hybrid consensus of PBFT combined with Bonded PoS, ensuring both high security and scalability. By separating consensus from application logic, Tendermint achieves enhanced modularity and scalability, while also offering the ABCI interface for application logic interactions.

New Multi-Chain Narrative: Superchain

「The core goal of Cosmos is to achieve interoperability and interactivity among different blockchains. The current focus of the Layer2 War seems to be steadily moving towards this goal」

The common goal of Layer2 solutions is to enhance the throughput and scalability of the Ethereum network to meet the ever-growing transaction demands. However, the competition among these Layer2s is shifting from solely performance improvements to a broader focus on interoperability and interaction, and even to the broader ecosystem.

1. Interoperability: With the emergence of more and more blockchain projects and Layer2 solutions, users and developers hope to seamlessly transfer assets and data between different blockchains. Achieving interoperability offers users greater flexibility, allowing them to flow freely across various blockchain networks.
2. Interactivity: The competition among Layer2 solutions drives developers to create more universal technical standards to ensure interactivity between different Layer2s. This interactivity will foster collaboration and data exchange between various Layer2 networks, resulting in a richer ecosystem.
3. Synergistic Effect: Similar to Cosmos’s Hub-and-Zone architecture, the interoperability between Layer2 solutions can create synergistic effects. Interconnection among different Layer2 solutions will enhance the overall ecosystem’s value, attracting more users and developers to participate.
4. Reduced Friction Costs: Achieving interoperability between different blockchains and Layer2s will reduce friction costs for users. Users will no longer need to go through tedious exchanges and transfers between different networks, thus enhancing user experience and engagement.

• Below is a comparison of Layer2s’ approaches and paths:

Source：Stacy Muur、l2beat、OP Research｜20230827

Optimism

「OP Stack is like arranging more seats for a large family gathering, ensuring everyone can join without having to shuffle around.」

Optimism Rollup and OP Stack

Optimism Rollup (ORU) is a Layer 2 (L2) scaling solution based on Ethereum (L1). Its design philosophy leverages the consensus mechanism of L1 to ensure the security and scalability of L2, avoiding the introduction of separate consensus mechanisms. As part of the parent-chain to child-chain model, ORU positions the parent chain as L1, with Ethereum playing this role.

The operational mechanism of ORU consists of three primary steps:

1. Data Storage (Blockstorage): Transactions on L2 are organized and written into blocks, which are then compressed and written onto L1. This method preserves data availability, ensuring transaction data can be accessed as needed.

2. Block Production: This phase involves the operation of the sequencer, responsible for constructing and executing L2 blocks. This process encompasses transaction confirmation, new block creation, and relaying pertinent information to L1 for transaction submission.

3. Block Execution: This stage ensures new blocks are received and maintains the stable operation of the L2 network.

On the other hand, the OP Stack is a standardized development stack that supports Optimism technology. From a tangible perspective, viewed hierarchically from bottom to top:

• Data Availability Layer (DALayer): This defines the source of raw data for L2. Currently, the Ethereum main chain plays a primary role here.

• Sequencing Layer: Functionality at this level is carried out by the sequencer, overseeing transaction confirmation, state updates, and L2 block construction.

• Derivation Layer: This layer determines how to process raw data from the Data Availability Layer to form processed inputs. These inputs are relayed to the Execution Layer via the standard Ethereum engine API.

• Execution Layer: This defines the state structure of the L2 system, supporting the Ethereum Virtual Machine (EVM) or other virtual machines. It also incorporates some L1 data costs into transactions.

• Settlement Layer: Responsible for relaying L2-confirmed transaction data to the target blockchain for final settlement.

• Governance Layer: The current approach sees multiple chains based on the OP Stack sharing the same set of governance standards.

Source: Structure of OP Stack | Origin: Binance Research

Note: optimism.mirror.xyz

Superchain

Superchain enables different Layer 2 (L2) solutions to collaborate by sharing security measures, communication layers, and the development toolkit (OP Stack). In traditional Layer 1 (L1) designs, scalability and performance often become limiting factors. Superchain addresses this by integrating multiple L2 networks, offering enhanced scalability and performance. This horizontal expansion not only grants the system a higher capacity but also delivers a superior experience for both developers and users.

Serving as a nexus for various L2 solutions, the OP Stack-based Superchain supports the large-scale operation of diverse blockchains and decentralized applications (dApps). The OP Stack, a standardized development stack that underpins the Optimism technology, integrates different L2 networks, fostering interoperability among them. By consolidating numerous L2 solutions into the Superchain, it achieves more efficient and flexible cross-chain communication. This enables users to seamlessly transfer assets and information between different L2s, unlocking a multitude of possibilities.

A hallmark attribute of Superchain is its modularity. Leveraging the OP Stack as a foundational development layer, individual L2 networks can selectively adopt layer modules, combining various technological components to cater to specific requirements. This modular design not only enhances system customization but also provides an easy entry point for new technologies and innovations. Furthermore, Superchain emphasizes interoperability, allowing different L2 solutions to effectively share resources and transfer information. The OP Stack-based Superchain presents a more cost-effective deployment option, encouraging a wider range of developers and projects to get involved. This is instrumental in advancing the broader development and adoption of L2 networks.

Superchain Architecture: Originating from the OP Official

In reality, issuing more Layer2s using the OP Stack is only the first step in establishing Superchain. A fully developed OP Stack requires Layer2s to share sorters, exchange economics and information, and establish a unified security governance mechanism and inter-chain ecosystem. Taking BASE as an example, the collaboration between Optimism and BASE has two main components:

1. Protocol Management: BASE adheres to the Law of Chains and joins the op-geth and op-node client operations. At the same time, it adopts the op-reth fault-tolerant client designed by paradigm and establishes the Pessimism monitoring system.

2. Economics and Governance: BASE will charge either 2.5% of its sorter revenue or 15% of the public chain profits after deducting L1 Gas (whichever is higher) as fees for using the OP Stack. In return, Optimism will provide BASE with up to 2.75% of the total OP supply as a reward for participation in governance. BASE and Optimism will jointly establish a Security Council to manage multi-signature contract upgrades and devise challenger key management plans to prevent unilateral malfeasance by team members.

Simply put, any blockchain network built on the OP Stack can flexibly combine different tier modules of the OP Stack to construct L2s. Optimism, now referred to as the OP Mainnet, serves as its first L2, collaboratively building the Superchain ecosystem. This approach makes the entire ecosystem more adaptable, meeting a variety of different demands and innovations.

Arbitrum

Unlike Optimism’s Superchain strategy which is based on the OP Stack to construct L2s, Arbitrum’s Orbitchain approach allows for the creation and deployment of Layer3, also known as application chains, on the Arbitrum mainnet (which includes Arbitrum One, Nova, and Goerli) using the Arbitrum Nitro technical stack, similar to OP Stack.

Source: Orbitchain Architecture: ARB official website

Differing from Optimism’s Superchain, Arbitrum has adopted a more flexible and customizable method. Orbit is a development framework that allows any developer to build L3 (application chains) based on ARB, culminating in the final architecture known as the Orbit chain. The design goal of the Orbit chain is compatibility with the upcoming Arbitrum Stylus upgrade. This compatibility facilitates developers in building decentralized applications (dApps) using programming languages like C, C++, and Rust. By leveraging these languages, developers can construct feature-rich dApps without needing to migrate to a new technical stack. This offers greater flexibility and choice for dApp developers, allowing them to better meet the needs of various projects.

Source: Orbitchain Architecture: Derived from ARB official documentation

However, at present, Arbitrum Orbit is still in a testnet phase and has not yet achieved the module completeness of OP Stack.

ZKSync Era

“Sovereignty and seamless integration” are at the heart of the ZK Stack narrative. Developers have full autonomy in customizing Hyperchain. Hyperchain operates independently, relying solely on Ethereum Layer1 for security and liveliness. The Hyperbridge network facilitates interconnection between Hyperchains. ZK Stack, launched on June 23, 2023, aims to build custom ZK-supported L2 and L3 based on the ZKSync Era code. Hence, technically, it’s indistinguishable from the OP Stack.

ZK Stack is a framework designed for building modular, sovereign Hyperchains based on zero-knowledge technology. It addresses the challenges posed in the “ZK Credo,” aiming to provide a foundation for decentralized blockchain networks. Core features of the ZK Stack include being open-source, composability, modularity, verified security, and scalability for the future.

This framework was developed by Matter Labs and uses the MIT/Apache open-source license. Hyperchains built with ZK Stack can seamlessly integrate within trustless networks, boasting low latency and shared liquidity. Developers can tailor Hyperchains according to their needs while ensuring security and reliability. The ZK Stack, built on the ZKSync Era code, leverages Hyperbridge for interoperability between super chains, achieving fast and cost-effective interoperability. Developers can customize super chains and connect them through Hyperbridge, ensuring trustless, rapid, and low-cost interoperability.

ZK Stack is suitable for scenarios requiring customized Hyperchains or asynchronous connections in a broader ecosystem since the L1-L2 bridge is asynchronous. Architecturally, the ZKSync Era has two application scenarios:

• 1) As one of the L2s Hyperchains, interconnected with peer L2s, sharing liquidity and other ecological resources.

• 2) Serving as the DA Layer for L3s.

Hyperchain resolves trust issues by verifying off-chain computations and utilizes zero-knowledge proofs for security. Hyperbridge connects super chains, facilitating data transfer and interoperability. Through Hyperbridge bridging, Hyperchain offers features like verified bridging, local bridging, and data availability, thus constructing a unified liquidity network. From a user perspective, Hyperchain achieves seamless interoperability and cross-chain wallet management, enhancing user experience. Technologically, the foundation of Hyperbridges consists of Hyperchains based on verified bridges, shared validators, and data availability.

Source：matter-labs

In summary, the scalability and composability of Hyperchain are at the heart of its design. Hyperchain’s L3 can connect with other L3s of the same level and can also directly use Ethereum as its DA layer. In this case, this L3 essentially becomes an L2. As illustrated in the diagram, the second Hyperchain L3 in the top left corner serves as the most direct proof of this. However, as a public chain for ZK Rollup, Layer2s not only need to bridge the gap with the Solidity programming language but also need to have the capability to independently develop ZK circuit systems. Otherwise, they can only rely on shared ZKPorters for operation. Currently, ZKSync lacks a comprehensive component-sharing mechanism, indicating that Hyperchain’s language and technical requirements have deterred many developers. Although ZK Rollup technically allows for millions of PTS in transaction volume while maintaining decentralization, the cost of ZK Proof is higher. Combined with the centralization of the sequencer and higher gas fees for complex smart contracts that may also fail due to compatibility issues, it makes rapid growth challenging for ZKSync in the short term. Therefore, there is no plan to issue tokens to promote its growth. Addressing this, ZK Sync has made certain optimizations in its Hyperchain architecture. The system’s LLVM compiler supports both Solidity and any other modern programming languages, enhancing accessibility for developers specifically using Rust, C++, and Swift. However, all things considered, Hyperchain remains the most challenging to develop.

Source：matter-labs

However, the ZK Stack is still in the development phase and has not been launched on the testnet yet.

StarkNet

「Fractional Scaling」：StarkWare believes that multiple Layer 3s will be built atop Layer 2, just as multiple Layer 2s are built on Layer 1. Here, L2 is used for general scaling, while L3 is intended for customized scaling. Fractional scaling achieves expansion by recursively adding layers. The introduction of L3, built recursively upon L2, offers higher scalability, superior tech stack control, and enhanced privacy for specific applications. L3 provides the advantages of massive scale, better performance control, and privacy protection while maintaining the security of L1. This transition will allow StarkEx (currently used as an L2 solution) to migrate to L3, and standalone instances of StarkNet will also be provided as L3.

At the Ethereum community conference EthCC held in Paris, StarkWare’s co-founder Eli Ben-Sasson announced the upcoming Starknet Appchain. Appchains are application blockchains specially designed to cater to specific application needs. Starknet Appchains aim to provide developers with a tailored environment, allowing them to create customized StarkNet instances for better standard control, reduced costs, larger scale, and optional privacy. By establishing StarkNet appchains, developers can offer higher throughput and an improved user experience for their users. The StarkNet Stack is constructed using modules like STARK proofs, the Cairo programming language, and native account abstraction.

Source: Official Documentation

Overall, the StarkNet Stack is still in its early stages of development, and the chain ecosystem is in its infancy.

Polygon2.0

In its overarching design philosophy, Polygon 2.0 aims to establish its Polygon’s PoS Mainnet and ZKEVM as the backbone of Polygon. Concurrently, it introduces Supernets application chains to bolster Polygon’s ecosystem. The primary beneficiary of this approach is the POL token. That’s because the Supernets in Polygon 2.0 need to stake POL tokens to run nodes, ensuring the public chain’s security. To achieve this, Polygon instantly offers PoS nodes, ZKEVM nodes, and Miden VM as three options for users. To enhance its appeal, Polygon has also introduced a zero-knowledge proof-based Polygon DID and a Web3 game development guide named “Blueprint.” It’s evident that Polygon 2.0 aims to nurture and thus draw a richer ecosystem for itself. Moreover, in its presentation of Supernets, Polygon 2.0 frequently touches upon the concept of enterprise blockchain. Collaborations with major brands like Starbucks, Nike, and Warner Music suggest its strategic moat lies in offering enterprise-grade, highly-customizable application chains with low entry barriers.

Structurally, Polygon 2.0 is reminiscent of the OP Stack. It’s segmented into several layers, namely:

• Staking Layer
• Interop Layer
• Execution Layer
• Proving Layer

This hierarchical design mirrors:

• Link
• Network
• Transport
• Application Layer

These are inspired by internet protocol components. Each protocol layer handles a specific sub-process, collectively forming the technical stack.

Staking Layer

The function of this staking layer aligns closely with Ethereum’s PoS (Proof of Stake), but its utility isn’t limited to just the Polygon mainnet.

Apart from the original Polygon mainnet, there are also the ZKEVM and Supernets. As such, Validators will be providing services for multiple chains, operating in a manner akin to re-staking, all managed by the Validator Manager. The responsibility to manage validators across all these chains falls on the Chain Manager contract. Every chain has its Chain Manager contract to decide the number of validators and any additional requirements for them, such as adhering to specific regulations or the necessity for additional token staking. This means validators might need to stake specific tokens of that chain to participate in its validation.

In reality, this staking layer is the crux of Polygon 2.0. Unlike Optimism and Arbitrum, for Supernets to operate, they require the support of validators who’ve staked $POL. The more Polygon chains there are, the more validators are needed, which in turn increases the value of the POL token. However, the re-staking model also allows Supernets teams to focus on utility and community rather than infrastructure, thereby reducing entry barriers for public chains.

Interop Layer

The Interop Layer uses ZK Proof to implement native cross-chain functionalities similar to Cosmos. By extending the LxLy protocol used in Polygon’s ZKEVM rollup, Polygon introduces an Aggregator to realize atomic cross-chain operations. Firstly, it can accept both ZK proofs and Message Queues. Additionally, it can aggregate multiple ZK proofs into a single ZK proof and submit it for Ethereum verification. Therefore, it acts as a middleware between Polygon and Ethereum.

Thus, when a Message Queue and ZK proof sent from Chain A are received by the Aggregator, Chain B, serving as the target chain, can directly receive messages from Chain A, facilitating seamless cross-chain interactions. Of course, Polygon is also exploring decentralizing the Aggregator using a PoS Validator model.

Execution Layer

Its execution layer functions similarly across different chains. This layer encompasses P2P, Consensus, Memepool, Database, and the Witness generator unique to ZK proofs.

Proving Layer

The Proving Layer is specific to ZK-Rollup, and it fundamentally serves as a protocol for generating ZK proofs for all transactions on the Polygon chain. It mainly consists of a generic prover and a state machine. The generic prover inherits from Plonky2, which uses recursive SNARK technology. In contrast, the state machines come in forms provided by the Polygon team, like ZKEVM and MidenVM, or are constructed by public chain teams themselves, such as ZKWASM.

Summary

Open-source Technology Perspective

OP Stack is warmly received by many projects. Over a dozen projects, including Base/Magi/opBNB/Worldcoin, have announced their use of OP Stack, and this popularity isn’t without reasons. One significant factor is the licensing openness. As evident from the data, Optimism uses the MIT License, while Arbitrum/ZKSync/Starknet/Polygon deploy the Apache License 2.0. Although both are open source, the openness of these licenses differs. The MIT License merely requires retaining the original license and copyright notice and allows commercial use, distribution, modification, private use, addition of terms, and even the sale of MIT licensed code. In contrast, the Apache License 2.0 necessitates highlighting modifications in the altered files. Derivative projects must include the original Apache-2.0 license, trademarks, patent declarations, and other author-specified notices. If a Notice file is present, it also must contain the Apache-2.0 license. In simple terms, the MIT License is more lenient, while the Apache License is more stringent.

Compatibility Perspective

• 1）Optimism boasts a high compatibility level with Ethereum’s EVM. With 12,745 commits and 2.3k forks for Optimism, this indicates a vast amount of code updates and a high developer adoption rate.

• 2）Technically speaking, the ZK series fully leverages Ethereum’s security and consensus mechanism, relying directly on its safety. Compared to the OP series, the ZK series can directly verify state changes without waiting for underlying state updates, streamlining design and enhancing cross-chain efficiency. However, OP faces limitations in asynchronous cross-chain calls, awaiting the foundational verification and confirmation.

Technical Architecture Perspective

• 1）Currently, both Optimism and Polygon focus on expanding L2s, while Arbitrum, ZK Sync, and Starknet are centered on L3s expansion. L3 application chains have greater freedom, scalability, and autonomy. However, the market is still developing on Layer2, with Layer3 seeming distant in the foreseeable future. Crucially, no cross-chain operations on L3 have been fully realized technically. Under these circumstances, dApps emphasizing composability will naturally opt for Layer2 for their DeFi Lego constructions.

• 2）Modularization and SDK components are the contemporary paths for blockchain. Whether it’s a public chain for dApps or Stack for Layer2/Layer3, the aim is to lower the programming barrier and optimize customization to reduce developers’ project construction costs. This allows them to concentrate on product design and community operations. Some projects, like AltLayer, emphasize “Rollup As A Service” as their core business. Thus, codeless blockchain creation and project launches will inevitably become common with the maturity of infrastructure.

Development Progress Perspective

Currently, only OP Stack and Polygon2.0 are developing at a swift pace. However, the ecosystem development of OP is the fastest, with already established public chains, while Arbitrum, ZKSync, and Starknet are still in their nascent stages. Given the undeveloped mainnet ecosystems of ZKSync and Starknet, it’s conceivable that they might be developing strategically to compete with OP Superchain. However, when examining decentralization levels, Starkware’s ZK proof generator, STARK Prove-Stone, went open source under the Apache2.0 license on August 31. In comparison, OP Stack, even with Base’s assistance, doesn’t have a decentralized sequencer on the horizon, suggesting Starkware might lead the race towards decentralization.

Comparison of Multi-chain Narratives and Superchain Narratives

Layer2 Cross-Chain, IBC, and Keplr Wallet

A primary narrative of Layer2 multi-chain is atomic cross-chain transactions. OP Stack uses a shared orderer to achieve inter-chain communication similar to IBC. Polygon2.0 utilizes a public set of validators and shared security through heavy staking to evolve into the “Polygon Hub”.

However, the cross-chain capability of Layer2 is still at the narrative stage. The only practical use is the EVM cross-chain based on the bridge model (wormhole/layerzero/axelar). The difference between this and IBC is quite evident. SEI’s recent cross-chain airdrop highlighted this difference: USDC transfers using Wormhole from Ethereum/Arbitrum/Polygon/BSC had to wait 24h to move out of SEI chain because they exceeded Wormhole’s cross-chain quota for SEI. In contrast, ATOM and OSMO transferred via IBC from Osmosis to SEI could instantly return to the original chain. Axelar USDC, part of the IBC ecosystem, also saw increased adoption. Yet, due to SEI’s official bridge and Axelar’s cross-chain mechanism, there was approximately a half-hour wait time to enter or exit SEI. Still, a direct transfer to an IBC public chain was instantaneous. The difference between a 24-hour wait and instant transfer speaks volumes.

Switching between chains on Layer2 in MetaMask offers a notably different user experience compared to Keplr. With the growth of Layer2 public chains, the need to switch between chains has gradually increased. But assets and interactions of different chains on MetaMask are separate, requiring third-party tools for unified management, increasing financial risk. Meanwhile, the Keplr wallet can display the fund amounts and statuses across the entire ecosystem. The strategy for Layer2 may require a “Super Wallet” like Keplr to unify its ecosystem assets.

Shared Orderer, ISC, and Block Auctions

The orderer is crucial to both the revenue and security of Rollups. A shared orderer allows new Layer2 solutions to skip the construction and maintenance of their own orderers and to benefit from the MEV income of all chains, thus reinforcing the value of the Superchain. However, this means sharing underlying security. Current Layer2 Stacks’ orderers are too centralized, with only PoS orderers and multi-organization multi-signatures taking a step closer to Vitalik’s Stage2 vision. So, shared orderers and decentralized orderers are necessary both for expanded profits and ensured security in the future.

A key to Cosmos’ revival, ICS lowers the entry barrier for the Cosmos ecosystem public chains and brings more value to the ATOM token. In the past, each part of the Cosmos ecosystem used PoS to ensure its security. ATOM was only used for Cosmos hub security, limiting its use to earning basic PoS returns or staking for airdrops. This situation resembles the current status of Layer2. OP Stack opted for Layered Security with Superchain, while Polygon2.0 chose Mesh Security through Restaking. Block auctions price MEV, addressing MEV from a business perspective and quantifying the value of orderers. With the establishment of a shared orderer, the MEV value naturally skyrockets. Superchain’s MEV income cannot merely be pocketed by orderers. Hence, Stacks block auctions will likely launch shortly after the shared orderer’s implementation.

Source：Delphi Digital

Conclusion: Cosmos is the Ultimate Form of Layer2

Given Layer2 Stacks’ acknowledgment of the Cosmos model, distinctive mechanisms within the current Cosmos ecosystem will likely be quickly adopted and optimized. For instance, Layer2 may emulate public chains like Berachain/Injective/Sei/Canto by introducing foundational liquidity at the public chain level, Terra-like native stablecoins, native lending at the public chain level, gas sharing mechanisms, modular contract deployments, and block auctions. Alternatively, as mentioned, there could be the development of a Keplr-like wallet for the Stack ecosystem to consolidate ecosystem assets.

Yet, the most vital and currently missing Cosmos mechanism for Stacks is a comprehensive inter-chain security. Different Layer2 Stacks could share orderers, decentralizing at the orderer layer rather than just individual orderer decentralization, mitigating single orderer risks. Additionally, PoS-based orderers can serve a single chain through methods similar to heavy staking. This echoes Cosmos ICS’s Layered Security and Mesh Security concepts.

The market is indeed seeking a figure similar to Cosmos or an OP superchain, serving as a hub connecting different blockchain networks. By creating synergy and sharing ecosystem resources, this entity would foster growth across the entire ecosystem. If the OP Stack method proves unfeasible, a new solution might emerge to fill the gap.

Whether the role ultimately taken is akin to ARB Orbit, OP Superchain, or ZK Stacks, they will play a pivotal part in Layer2 scaling. With the maturation of ZK technology and its wider accessibility, ZK-based or ZK-integrated OP Stacks may take up the mantle of Layer2 multi-chain. With inherent high TPS and decentralization, these are crucial attributes for scalability, apart from compatibility, and are technically guaranteed in high security sharing contexts. While ZKSync and Starknet’s development may be slower, their TVL and user base growth are undeniable. Thus, it remains to be seen whether OP Stack’s early advantage and compatibility will rapidly capture the Stack market, or if the ZK Stack’s high TPS and decentralization can surge forward as the technology matures.

Reference

[1]《Layer2四大天王争先布局Stack背后的原因》 https://haotiancryptoinsight.substack.com/p/layer2stack

[2]《超级链来临：深度解读 Coinbase 和 Optimism 联手打造的 OP Stack》https://www.8btc.com/article/6806138

[3]《Crazy Multichain Universe, Crazy OP Stack》https://medium.com/ybbcapital/crazy-multichain-universe-crazy-op-stack-acb63be8d515

[4]《Introduction to Hyperchains》https://medium.com/matter-labs/introduction-to-hyperchains-fdb33414ead7

[5]《Introducing the ZK Stack》https://medium.com/matter-labs/introducing-the-ZK-stack-c24240c2532a

[6]《ZKSync生态进程与去中心化进程的变量》https://twitter.com/tmel0211/status/1663034763832344576

[7]《A gentle introduction: Orbit chains》https://docs.arbitrum.io/launch-orbit-chain/orbit-gentle-introduction

[8]《The Starknet Stack’s Growth Spurt》https://starkware.co/resource/the-starknet-stacks-growth-spurt/

[9]《开源许可证的区别》https://www.geek-workshop.com/thread-1860-1-1.html

[10]《The Appchain Universe: The Risks and Opportunities》https://medium.com/alliancedao/the-appchain-universe-the-risks-and-opportunities-9a22530e2a0c

[11]《Application-Specific Blockchains: The Past, Present, and Future》https://medium.com/1kxnetwork/application-specific-blockchains-9a36511c832

[12]《The Inevitability of UNIchain》https://medium.com/nascent-xyz/the-inevitability-of-unichain-bc600c92c5c4

[13]https://defillama.com/chains

[14]https://dune.com/Marcov/Optimism-Ethereum

[15]https://dune.com/gopimanchurian/arbitrum

[16]https://dune.com/gm365/L2

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