Detailed Explanation of ZK Stack by zkSync: A Killer Feature Competing with Optimism and Arbitrum?
On the evening of June 26th, zkSync announced the launch of ZK Stack, a modular open-source framework for building custom zkRollups, aiming to empower developers with full autonomy, from choosing data availability patterns to using their own project’s token as the decentralized sequencer. ZK Stack offers two key functionalities: sovereignty and seamless connections. These zkRollup chains run independently, relying only on Ethereum L1 for their activity and security, while also featuring cross-chain bridges to enable interoperability between chains in a trustless, fast, and cost-effective manner.
The launch of ZK Stack brings to mind the scalability solution, OP Stack, previously introduced by the Optimism team. As a standardized open-source module, developers can assemble a custom chain using OP Stack to serve any specific blockchain use case. The design of OP Stack allows for easier code forking than current efforts, as developers can easily abstract different components of the blockchain and modify them by inserting different modules.
By announcing a product similar to Optimism and Arbitrum's ecosystems before the mainnet token launch, ZK Stack is considered by many as zkSync's secret weapon against OP Stack and Arbitrum Orbit. So, what are the features of ZK Stack? How does it compare to OP Stack?
ZK Stack
Last week, the zkSync team shared the initial draft of ZK Credo, clarifying the key attributes of decentralized blockchain networks and the necessity of ZK as the foundation of the emerging value internet. The launch of ZK Stack is based on the team's vision for scalability.
According to the official documentation, ZK Stack is a free modular open-source framework designed to build custom ZK-driven L2 and L3 based on zkSync Era's code. The core of ZK Stack provides two key functionalities: sovereignty and seamless connections, giving creators unrestricted autonomy to customize and shape various aspects of the chain. Overall, ZK Stack has three main characteristics: open-source, composability, and modularity.
ZK Stack is developed under the fully permissive MIT/Apache open-source license, ensuring its free availability for developers to contribute to and use according to their needs. Additionally, the superchain built with ZK Stack can seamlessly connect in trustless networks, offering low latency and shared liquidity. Furthermore, ZK Stack assists developers in customizing and shaping their own Hyperchain, from choosing sorters and data availability patterns to defining their own token economies.
Paradigm Shift
For the zkSync core team, ZK Stack represents an important paradigm shift. Previously, the team focused on building mature ZK technology and introduced EVM-compatible ZK Rollup—zkSync Era earlier this year. The launch of ZK Stack signifies a shift in the team's work focus from technology to community. With the introduction of more Hyperchains, the zkSync ecosystem aims to substantially increase the number of core contributors and make the community the true owners of the zkSync ecosystem network.
Similar to OP Stack, deploying a Hyperchain for their applications will be a simpler process for developers and allows asynchronous connections with other protocol implementations in the ecosystem for various interoperability functionalities. In the ZK Stack documentation, the team lists several potential use cases for Hyperchains:
1. When building a game or social network that requires a lightweight sorter not burdened by other dApps and use cases;
2. When constructing a DeFi application chain that emphasizes low-latency sorting;
3. When enterprises build internal private chains while desiring interconnectivity with the Ethereum ecosystem.
Super Scalability
In addition to scalability features, ZK Stack's notable characteristic is its strong interoperability. ZK Stack allows developers to build their own sovereign chains without sacrificing interoperability and composability. Each Hyperchain can seamlessly integrate into zkSync's ecosystem, supported by shared provers and fractal expansion, forming a complete liquidity network.
Through ZK Stack's architecture, smart contracts on each Hyperchain will be able to asynchronously invoke each other across chains, enabling users to swiftly transfer their assets in a trustless manner within minutes and without incurring any additional costs. Simultaneously, the superchain itself will have full sovereignty, the ability to join other ecosystems, and take away its on-chain assets.
ZK Stack team stated that in the coming weeks, they will make modifications to the codebase to make it easier to check out, configure, and deploy instances of ZK Stack, with the ultimate goal of achieving one-click deployment, just like OP Stack.
OP Stack
Next, let's review OP Stack, which has already been released and adopted by many teams. In October 2022, Optimism, a second-layer scaling solution for Ethereum, introduced the modular open-source blueprint OP Stack. The Optimism team sees it as the next evolution stage of scalability architecture, applicable to various highly scalable and highly interoperable blockchains. OP Stack is based on the originality of the entire Ethereum community and is a standardized open-source module that developers can use to assemble a blockchain serving specific use cases. The design of OP Stack allows developers to fork Optimism's code more easily by abstracting the various components of the blockchain and inserting different modules to modify the Optimism code. For example, when an Optimistic Rollup wants to transform itself into a ZK Rollup, it only needs to replace its fraud proof module with a validity proof module for the settlement layer.
Related reading: "Exploring OP Stack: Optimism's Vision for Modular Expansion".
Open Garden
OP Stack first introduced the concept of the "Open Garden", where OP chains that voluntarily choose to join the same shared sequencer set can enjoy atomic cross-chain combinations. If an OP chain does not want to run its own sequencer, it can pay a certain fee to use Optimism's trusted shared sequencers, which also opens up a revenue model for Optimism.
In accordance with this vision, Optimism refers to its OP chains as "Superchains". OP chains will fully interoperate on Optimism and be connected by the same technological structure. As the shared modules of OP Stack increase the flexibility of configuration, developers are repeating the recycling of reusable code previously used by other developers, making the code more powerful and more resistant to hackers and bugs.
Support from "Web3 Giants"
Shortly after the launch of OP Stack, it received support from the "Web3 giants". In February of this year, Coinbase announced the launch of a multi-chain L2 platform built on OP Stack. This collaboration aims to upgrade the Optimism mainnet, Base, and other L2 solutions to an initial superchain structure and share bridging and sequencing. As a blockchain on the OP platform, Base will return a portion of transaction fee revenue to the Optimism Collective Treasury.
Base, built on OP Stack, provides the security and scalability required to support decentralized applications. It leverages the underlying security of Ethereum, allowing users to access Base from Coinbase, Ethereum L1, and other interoperable chains. At the same time, Base offers complete EVM equivalence at extremely low cost and is committed to driving developer platform development. Additionally, developers on Base can easily build decentralized applications by accessing Coinbase's products, users, and tools, seamlessly integrating with Coinbase's product suite, and accessing $80 billion worth of assets to serve platform users.
Related reading: "A comprehensive understanding of Coinbase's Layer2 scaling solution Base"
Comparison: Stack, OP, and Sync
In addition to Coinbase, OP Stack, which enjoys the advantage of being a pioneer, has also gained the favor of "leading public chains" such as BNB Chain. On June 19th, BNB Chain announced the launch of a new scaling solution called opBNB and launched the opBNB testnet. With the surge in transaction volume in GameFi and other sectors, BSC also frequently faces network congestion and high gas fees. The original design and architecture have proven inadequate in meeting scalability demands. In this context, opBNB has emerged to provide new possibilities for addressing BSC's scalability issues.
opBNB is a layer 2 scaling solution built on top of BSC. It is also compatible with EVM and based on the Bedrock version of OP Stack. Similar to how Bedrock works, opBNB processes transactions off-chain and then publishes transaction data on-chain, thereby achieving compression of on-chain data and improving scalability.
Users interact with the opBNB network on opBNB through applications or directly through contracts; Sequencers aggregate transactions, compute state transitions, and submit them to rollup contracts on BSC; Provers generate cryptographic proofs to prove the validity of these state transitions; Verifiers check the proofs to verify the correctness of opBNB states.
Unlike Optimism and Coinbase's layer 2 solution Base, opBNB is built on BSC instead of Ethereum. BSC's performance is superior to Ethereum, so opBNB's performance is not only better than BSC, but also better than scaling solutions like Optimism. According to official descriptions, opBNB has a block time of 1 second, with gas fees as low as $0.005, and can process over 4000 transactions per second (TPS), surpassing existing scaling solutions.
Related reading: "A comprehensive understanding of opBNB, the Layer 2 network newly launched on BNB Chain"
In addition to public chains like BNB Chain, many application development teams choose to develop their own application chains based on the OP Stack:
On March 1st, the game digital economy platform Cocos-BCX announced a global strategic partnership with NodeReal to jointly develop the first Web3 game-centric rollup Layer 2 on BNB Chain based on the Optimistic (OP) Stack. This cooperation combines Cocos-BCX's leading Web3 game extension solution with NodeReal's comprehensive blockchain infrastructure to support over 1.6 million game developers in the development of 2D/3D games, metaverses, artificial intelligence (AI), and extended reality (XR).
On April 20th, a16z Crypto announced the launch of a new Optimism Stack rollup client called Magi. Magi is an OP Stack rollup client developed in Rust, which performs the same core functions as the reference implementation (OP-node) and works together with execution nodes (such as OP-geth) to synchronize with any OP Stack chain, including Optimism and Base.
On June 22nd, NFT trading platform Zora announced the launch of ZORA NETWORK, a Layer 2 network based on OP Stack. This network provides artists, creators, and communities with a faster and more efficient Ethereum extension, and will directly integrate all existing Zora tools. Zora Network has issued a Layer 2 NFT minting platform based on OP Stack, targeting NFT creators, brands, and collectors, providing a series of NFT creator tools, and reducing minting costs to less than $3.
So, has OP Stack, which has the first-mover advantage, already won the battle for L2 scalability against ZK Stack?
After the announcement of ZK Stack, the community also made a detailed comparison between the two from a technical perspective. Blockchain researcher Haotian (@tme l0 211 ) pointed out in a tweet that HyperChain does not need to maintain state and consensus and can directly rely on the security of Ethereum. Moreover, compared to the interaction fraud proof of OP Rollup, HyperChain can directly verify state changes using ZK proofs without waiting for the underlying state changes in Ethereum, thus improving the efficiency of cross-chain interaction. In contrast, OP Stack still has limitations in asynchronous cross-chain calls, as its state changes need to wait for verification from the underlying Ethereum.
It can be seen that on one hand, there is OP Stack with the first-mover advantage, and on the other hand, there is ZK Stack with technological advantages. The battle for L2 scalability has just begun. Undoubtedly, regardless of who ultimately wins, the narrative around multi-chain scalability of Ethereum is gradually becoming an important driving force for igniting a new cycle of the crypto industry.
