Arbitrum’s airdrop in March 2023 marked the beginning of a thriving year for Layer 2. Due to the wealth effect, a large number of users flocked to interact with other Layer 2 projects that had not yet distributed tokens, especially the remaining zkSync and StarkNet, known as the ‘Big Four of Layer 2.’ Even projects on the Goerli testnet attracted user engagement. On the contrary, in the new Layer1 Blockchain space, both user activity and the ability to innovate new projects appeared sluggish during the bear market. Layer 2 projects fiercely competed with each other, showcasing their strengths in technology, ecosystem, and operations. Here, we will take stock of the distinctive features of various Layer 2 projects and speculate on future trends in the Layer 2 space.”
This research report is produced by HTX Ventures, the global investment arm of HTX. HTX Ventures employs an integrated approach that combines investment, incubation, and research to identify the most exceptional and promising teams worldwide. As a pioneer with a decade of experience in the blockchain industry, HTX Ventures is committed to exploring, uncovering, and driving the development of cutting-edge technology and emerging business models within the industry. It offers comprehensive support to collaborative projects, including financing, resources, and strategic consulting, to foster the growth of the blockchain ecosystem.
Established in 2017, HTX Ventures covers the entire investment cycle and specializes in investing in Layer 1 and Layer 2 solutions. To date, HTX Ventures has achieved a 60-fold return on investment, with investments spanning over 20 countries and regions. It has collaborated with more than 120 fund partners and has supported over 200 projects across various disciplines, with 60% of these projects eventually being listed on HTX.
As a globally leading digital asset exchange since 2013, HTX has the infrastructure and resources to offer expert advisory services, empowering HTX Ventures’ portfolio projects with access to HTX’s extensive resource network, liquidity pool, and user base.
- The Rise of the Layer 2
As the cryptocurrency space continues to evolve, there is an increasing need for blockchains to accommodate more users and interactions. Ethereum’s mainnet can only process approximately 15 transactions per second, and the substantial demand has led to network congestion and high fees, excluding some potential users. Ethereum needs to implement scaling solutions to address these issues, and that’s where Layer 2 comes into play. Layer 2 primarily addresses scalability, transaction costs, transaction speed, and other related challenges. Layer 2 achieves this by regularly communicates with Ethereum (by submitting bundles of transactions), offering similar security and decentralization features as the Ethereum mainnet.
There are several different types of layer 2, each having their own trade-offs and security models. Based on technical classification, Ethereum Layer 2 could be classified as four major solutions: state channels, Plasma, Validium, and Rollups. However, with the advancement and evolution of technology, the Rollup solution has proven to be the most successful in improving performance, reducing costs, and providing a better user experience. Currently, Rollup is considered the preferred Layer 2 scaling solution for Ethereum.
The Rollup solution was first proposed in 2018 to address the scalability issues of the Ethereum blockchain. It involves moving transaction data off-chain and utilizing different validation methods to improve performance, reduce costs, and enhance security. These technologies have become one of the primary scaling solutions within the Ethereum ecosystem, providing a solid foundation for the future development of decentralized applications and the Ethereum network. The main types of Rollup include:”
- Optimistic Rollup: Optimistic rollups execute transactions outside of Ethereum, but post transaction data to Mainnet as calldata. Optimistic rollups are considered “optimistic” because they assume off-chain transactions are valid and If there is no dispute, transactions are confirmed, otherwise, dispute resolution is required. Representative projects include Arbitrum, Optimism, Base, Metis Andromeda, and Boba Network.
- ZK-Rollup: ZK-Rollup (Zero-Knowledge Proof Rollup) was introduced by Barry Whitehat in 2018. It incorporates zero-knowledge proof technology to ensure the validity of off-chain transactions, thereby enhancing security. The core idea of ZK-Rollup is to store transaction data off-chain and then use zero-knowledge proofs to verify their validity, reducing the burden on the L1 Blockchain. Representative projects include zkSync, Starknet, Scroll, Loopring, and Polygon zkEVM
Currently, due to the higher complexity of ZK-Rollup technology, most Layer 2 projects using this approach are progressing slowly. The largest share in the entire Layer 2 market is still held by the Optimistic Rollup solution. According to data from l2beat, there are currently 33 active Layer 2 projects, with 11 using Optimistic Rollup and 12 using ZK-Rollup. There are 15 projects set to be launched soon.
- The Current State of Layer 2 Projects
Since the crypto market entered a bearish phase in 2022, Ethereum’s DeFi TVL market share has remained at 54.06%. Meanwhile, the prices of tokens from new Layer 1 blockchains like Solana, Avalanche, Cosmos, and Polkadot have seen some declines. In contrast, Ethereum’s value has increased by over 20% during the same period. In 2023, there was a significant reshuffling in the landscape of new Layer 1 blockchains. For these new chains, becoming an ‘Ethereum killer’ is now highly unlikely. However, for Layer 2 projects, their performance in attracting funds, users, and developers from Ethereum has been notably better during the bear market. Layer 2 not only solidifies Ethereum’s position but also exhibits a ‘Flywheel effect,’ contributing to the growth of ETH’s value. The Layer 2 track has a strong potential to become a catalyst for the next bull market.
Figure 1. Total Value Locked All Chains (Source: DefiLlama)
Currently, the total market capitalization of projects under the Layer 2 sector stands at $9.25 billion, with a 24-hour trading volume of $1.13 billion. Optimism and Arbitrum are nearing a market capitalization of $1 billion. However, concerning the total number of developers actively working on their protocols, Starknet has stood out today, while zkSync has led in terms of daily active addresses and total transaction volume over the past month.
|Coin||Price||24h Volume||Mkt Cap|
Table 1. Top 7 Layer 2 Projects by Market Capitalization (Source: CoinMarketCap, Oct. 17, 2023)”
According to L2BEAT data, as of October 17, 2023, the total Layer 2 TVL amounted to $10.6 billion, reflecting a growth of 136.8% compared to the end of 2022. The project with the largest TVL share is Arbitrum One, standing at $5.80 billion, making up 54.69% of the entire Layer 2 project market share. Following closely is Optimism, accounting for 24.98%.
Figure 2. Top 10 Layer 2 Projects by TVL (Source: l2beat.com, Oct. 17, 2023)”
Arbitrum is built by the Offchain Labs. It leverages the optimistic rollup technology to scale Ethereum. Arbitrum One employs fraud proofs and features on-chain data availability, which means that all data for each transaction is fully ordered, bundled, and submitted to the mainnet. Due to Arbitrum’s use of fraud proofs, its withdrawal period is approximately seven days.
The most exciting event in March 2023 was undoubtedly the Arbitrum airdrop, which brought a significant wealth effect. Since the release of the airdrop rules, Arbitrum One’s TVL has steadily risen and currently stands at $5.80 billion, trailing only behind Tron and Ethereum itself. It occupies 54.69% of the entire Layer 2 ecosystem in terms of TVL, with over 11 million unique addresses and more than 330 projects.
Figure 3. Arbitrum weekly Active Addresses (Source: Dune, @Henrystats)
Arbitrum Ecosystem Review
The projects under Arbitrum ecosystem can be divided into two main categories: DeFi and consumer applications. In the DeFi part, projects mainly focus on DEX, lending, and perpetual contracts. There are four projects with a total value locked (TVL) of over 100 million dollars, namely GMX, Uniswap V3, Radiant, and AAVE V3.
|GMX||Perpetual Exchange, launched in August 2021, have a TVL of $400 million, ranking first in the Arbitrum ecosystem. GMX allows users to trade cryptocurrencies in a peer-to-pool manner without the need for intermediaries, in turn, earn a portion of the fees generated by the protocol.|
|Camelot||DEX, with a TVL of $55.33 million. Camelot combines the mechanisms of Uniswap V2 and Curve and aligns its liquidity incentives in a way similar to most DEXs.|
|Radiant||Lending Products, Radiant Capital is the first omnichain money market atop LayerZero, where users can deposit and borrow a variety of supported assets across multiple chains, seamlessly.|
|Pendle||An interest rate swap protocol based on future interest-bearing assets that allow users to execute various yield management strategies based on their risk appetite.|
|TreasureDAO||An ecosystem targeting game developers with the aim of becoming the ‘Nintendo of Web3.’ TreasureDAO includes The Beacon game, the game NFT trading platform Trove, and the ecosystem’s game token trading platform MagicSwap. The project token is $MAGIC.|
|Trident||Massively Multiplayer Online (MMO) Game|
Optimism was created by a group of Ethereum developers and is a Layer 2 scaling solution based on Optimism Rollup technology. It aims to handle a large volume of transactions while retaining Ethereum’s security. However, there are some differences in the technical implementation between Optimism and Arbitrum:
|Optimism||Both based on optimistic rollup technologyAll transaction data is stored on Layer 1 (L1).”both support EVM-related tools.||EVM equivalence；Single-round fraud proofs|
|Arbitrum||EVM compatibleMuli-round fraud proofs|
Currently, in terms of TVL, Optimism stands at $2.6 billion, ranking second among Layer 2 solutions. There are 173 protocols on Optimism, with over 5 million unique addresses.
Figure 4. Optimism Unique Users over time（Source：dune, @Marcov）
Optimism Ecosystem Review
Optimism has relatively fewer native projects, and apart from the DeFi projects, there are few high-profile projects. There are two projects with a total value locked (TVL) of over 100 million dollars, which are Synthetix and Velodrome.
|Synthetix||A decentralized finance (DeFi) protocol that enables the creation and trading of synthetic assets，In July 2021, with a TVL of $140.36 million, it ranked first in the Optimism ecosystem. Users can over-collateralize their native token SNX to mint the dollar-pegged stablecoin sUSD and trade various synthetic assets on its platform, including sETH, sBTC, traditional precious metals, and the stocks of well-known U.S. publicly traded companies.|
|Velodrome||DEX，The first to succeed and implement the practical ve(3,3) DEX, the code forked from Solidly developed by Andre Cronje on Fantom. It serves as the liquidity hub on Optimism and acts as a gateway for new projects and multi-chain projects, serving as the entry point to Optimism.|
|Sonne Finance||The first native platform to launch a lending protocol on Optimism, aiming to become a leading lending platform by providing the deepest liquidity and the most competitive incentives. Sonne employs Velodrome to help maintain ongoing liquidity and incentivize more activity on its platform.|
|dHEDGE||A decentralized asset management protocol that supports anyone in creating their own investment fund on Ethereum or Optimism chains, or investing in funds managed by others. Users can choose investment pools based on their preferences.|
|Beethoven X||A decentralized investment and trading platform based on Fantom and Optimism, built around the core concept of programmable liquidity.|
|Premia||It aims to deliver the best prices to users while bringing peer-to-pool derivatives trading and capital efficiency to decentralized finance (DeFi) options.|
Base Network was announced by Coinbase on February 23rd and went live on the mainnet in August. Base is built on OP Stack technology. The launch of Base facilitates the development and deployment of Coinbase’s own decentralized applications. In the future, with the integration of Coinbase Wallet and Smart contract wallet ( Account Abstraction technology), Coinbase’s customers can easily access the financial service protocols hosted by Base.
Over a month after its launch, BASE surpassed the daily trading volume of Layer 2 competitors and even Ethereum itself, reaching over one million on September 14th. The total user count is currently 2.1 million, with a TVL of $548 million, and over 100 projects within its ecosystem.
Figure 5. Base all transactions and Users Daily（Source：dune, @sixdegree）
Base ecosystem review
The success of the Base ecosystem is primarily attributed to friend.tech, while other projects are primarily focused on DeFi, and many are forks of projects from other blockchains.
|friend.tech||A social project launched on the BASE blockchain in August, where fans can access exclusive chat rooms with influencers and creators by holding their tokens. From August 25th to September 25th, friend.tech has generated $19.9 million in fees, ranking third among all decentralized applications, only behind Lido and Uniswap.|
|Aerodrome||A DEX incorporating the bribes mechanism, a fork of Velodrome on Optimism, with team members including core members from Velodrome and Base.|
|Scale||This is an expansion of the Equalizer project on the Base network, which is a native project on Fantom, and it utilizes Andre Cronje’s Solidly model.|
|BaseSwap||DEX, developed by the Base team for Base People, utilizes a dual-token model: the platform token BSX and the yield token BSWAP.|
|Moonwell||An open lending DeFi protocol based on Moonbeam and Base, similar to lending products like Aave, MakerDAO, and Compound, allowing users to over-collateralize and borrow cryptocurrencies.|
2.4 Zksync era
zkSync is developed by Matter Labs and utilizes zero-knowledge proofs to bundle multiple transactions into a single proof that can be verified on the Ethereum blockchain. zkSync Lite is the 1.0 version, and zkSync Era is essentially the 2.0 version of zkSync. The project has not yet released its token and is valued at around $40 billion.
Currently, zkSync Era network has a TVL of $428 million, and according to Dune Analytics data, the number of unique addresses on zkSync Era has reached 1.9 million, with 1.7 million ETH tokens bridged into the zkSync Era network.
zkSync cosystem review
According to Defillama data, there are 9 DeFi projects listed, primarily consisting of DEX projects. Additionally, there are 34 officially launched projects, including wallets, cross-chain solutions, NFT projects, and more. However, there are relatively few innovative projects, and there is still some gap in comparison to the OP ecosystem.
|Mute.io||A zkRollup based DEX, farming platform, and Bond platform built on Ethereum and zkSync. The native token is $MUTE, and it has the following features:Amplifier with Re-staking: The Amplifier allows users to restake LP tokens to earn higher returns.Bond Mechanism Inspired by OlympusDAO: Users can obtain MUTE Tokens at a discounted rate by trading MUTE/ETH LP tokens with the Mute DAO, similar to the mechanism used by OlympusDAO.Locking for DAO Governance: Users can lock $MUTE tokens to participate in DAO governance, similar to how it works in Curve.（https://mute.io/）|
|SpaceFi||It’s a cross-chain platform linking Evmos and zkSync, and they have released the SPACE Token. On zkSync Era, users can trade assets like ETH, USDC, WETH, and provide liquidity on SpaceFi. Additionally, SpaceFi will feature multiple functions such as FARM, NFT, SpaceBase, SpaceBridge, Launchpad, and more. https://www.spacefi.io/）|
|rhino.fi||It’s a multi-chain one-stop DeFi platform offering order book trading, DEX, yield strategies, liquidity provision, gasless internal transfers, and cross-chain functionality. Users can deposit ETH into this platform using the zkSync Era network. Currently, rhino.fi has launched the DVF Token, allowing participation in staking and governance. The governance module covers a wide range of topics, from transaction fees, transfer fees, liquidity rewards, to smart contract upgrades, allocation of funds from the treasury, and minting new DVF Tokens, among others.（https://rhino.fi/）|
|SyncSwap||a DEX, currently ranking first by TVL. Users can trade and provide liquidity on SyncSwap. The TVL is primarily concentrated in the USDC/ETH Pool, which is currently offering over 100% APR. The trading fee for the Classic pool is 0.1%, with liquidity providers earning 0.07%, and the protocol collects 0.03% as revenue.（https://syncswap.xyz/）|
|Fringe Finance||a decentralized financial ecosystem that includes lending, stablecoins, and RIN token staking functions. (https://fringe.fi/）|
|Meson||Meson is the faster and safer way to execute low-cost, zero-slippage stablecoin cross-chain swaps across all leading blockchains and layer-2 rollups （https://meson.fi/）|
|Nexon Finance||Lending Protocol（https://www.nexon.finance/）|
|kreatorland||It is an NFT launchpad and NFT marketplace on zkSync. The NFT project Skullverse is the first project launched on its launchpad. (https://kreatorland.com/)|
|Mint Square||It’s an NFT marketplace based on Ethereum Layer 2 ZK Rollups (StarkNet, zkSync). Users can mint, buy, sell, and auction NFTs on Mint Square. zkApe is the first NFT project launched on Mint Square.（https://mintsquare.io/）|
StarkNet is a ZK Rollup protocol released by StarkWare Ltd on the Ethereum testnet in November 2021. StarkWare focuses on creating cryptographic proof systems to enhance the scalability and privacy of various blockchain networks. They have utilized ZK technology to create two projects, StarkEx and StarkNet. StarkEx provides dedicated Rollup technology services for each application and officially launched in 2020. Projects developed based on StarkEX include Sorare, immutableX, dYdX, and others. StarkNet can deploy a general-purpose Rollup for any smart contract and has seen over 50 ecosystem projects go live. The Total Value Locked (TVL) in StarkNet is currently approximately $131 million.
With StarkWare currently valued at $8 billion, the credibility of StarkNet’s ecosystem projects is unquestionable. StarkNet announced the deployment of its native token $STRK on the Ethereum mainnet on November 16, 2022. This token is intended for voting, staking, and fee payments, although the token distribution is still pending a decision.
Starknet Ecosystem Review
Thanks to StarkNet’s high throughput and customizability, developers can create innovative, high-performance, and tailor-made dApps on StarkNet. This opens up many new possibilities for developers, leading to an array of innovative projects within the StarkNet ecosystem, with a focus on DeFi, NFTs, and the gaming field.
|10KSwap||AMM DEX, supporting swaps between five tokens: ETH, USDC, DAI, WBTC, and USDT.|
|Nostra||A lending protocol that supports flash loans and offers StarkNet’s first native stablecoin $UNO, Nostra consists of three products: Nostra Money Market, UNO, and Nostra Swap. The Money Market provides users with “collateralize to mint ” services similar to MakerDAO, enabling the minting of $UNO. The Money Market also generates revenue for Nostra Swap and UNO minters.|
|ZKX||A perpetuals trading platform with self-custody and community governance. ZKX has introduced a series of measures to incentivize users to trade, including trading and staking to earn USDC, increasing trading volume to unlock advanced ZKX features, and more.|
|Aspect||NFT trading platform where users can mint, upload, and buy/sell NFTs.|
|Mint Square||NFT Platform allow users to create and trade NFTs|
|StarkNet ID||Domain service (.stark) where users can attach any data to their StarkNet identity, including identity tags such as social media accounts from Web2 and Web3 ENS domain names.|
|cartridge.gg||A blockchain gaming platform that assists users in filtering blockchain games, interacting with friends, and integrates features like DID (Decentralized Identifier) and wallets for a comprehensive gaming experience.|
In addition to the well-known Layer 2 projects mentioned above, there are several other projects worth keeping an eye on:
- Linea: A zk rollup project supported by ConsenSys, with its mainnet already live. Currently, it hosts over 100 projects with a Total Value Locked (TVL) of $25.5 million.
- Scroll：The project has gained significant popularity and is ranked closely behind zkSync and Starknet in the zk rollup space, with its mainnet recently launched. Scroll secured a $30 million Series A funding round in April 2022 and another $50 million in July 2023, with a valuation of $1.8 billion. Scroll’s aim is to build an EVM-compatible zk-Rollup, with the team primarily composed of Chinese developers.
- Polygon zkEVM: An Ethereum Layer 2 built on ZK Rollup technology, formerly known as Hermez Network, acquired by Polygon for $250 million. The mainnet Beta version is live, with a TVL of $54.93 million.
- Loopring: A protocol designed to support DEX (Decentralized Exchange) built on StarkWare technology. Unlike other public networks, external developers cannot create their own generic protocols or products on Loopring; they can only utilize Loopring’s API. Moreover, since Loopring focuses on building its own products, the Loopring protocol is more than just a network, it encompasses a collection of several products.
- Immutable X: Built on StarkWare, it is specialized for specific applications and focuses on NFT and gaming ecosystems.
- Aztec: A project with a focus on privacy that has developed the PLONK proof system.
- Kakarot: A community-driven project that started in October 2022. It is written in the Cairo language and leverages the ZK-STARK proof system to provide verifiable computation capabilities. It enables developers to deploy EVM applications on it, allowing end-users to interact with these applications using their familiar toolchains.
- Taiko: Described as “fully decentralized, Ethereum-compatible zk-rollup,” currently in the testing phase. Taiko can accurately handle all Ethereum behaviors, using the same hash functions, gas prices, and encryption algorithms, among other things. One drawback of Type 1 ZK-EVM is that generating proofs takes a long time, and bridging ETH from Taiko L2 back to Ethereum L1 can take several hours.
Additionally, several Layer 2 Appchains are built on StarkEx, including projects like Sorare, rhino.fi, ApeX, dYdX, and more. In these projects, data is sent to Ethereum as calldata and published on-chain. In the Validium mode, data is stored off-chain, with only the hash values stored on-chain. While the Rollup mode ensures higher security (allowing users to recreate the ledger state by interacting with the Ethereum blockchain), the Validium mode can offer lower costs and enhanced privacy.
3. OP VS ZK
This year, Layer 2 projects have been launching their mainnets one after another, resulting in intense competition within the sector. Discussions about Optimistic Rollup and zk Rollup have never ceased. While zk Rollup theoretically offers superior performance, significantly faster finality, and higher security, Optimistic Rollup boasts better compatibility and a lower entry barrier. Furthermore, judging from the performance of Layer 2 projects, Optimistic Rollup has gained a first-mover advantage. Therefore, both of these solutions are expected to coexist in the medium to long term. Below is a comprehensive comparison of the strengths and weaknesses of Optimistic Rollup and zk Rollups from technical, user experience, and ecosystem development perspectives.
- HOW DO THEY INTERACT WITH ETHEREUM?
Optimistic Rollup operates by using a sidechain connected to the L1 blockchain to process off-chain transactions. The sidechain is responsible for processing transaction computations and verification, regularly sending its state summary to the L1 blockchain. In Optimistic Rollup, there is an assumption called the “Optimism” hypothesis, where the sidechain assumes that all transactions are valid and only submits proofs when fraudulent transactions are detected.
ZK Rollups batch multiple transactions together to be executed on the L1 blockchain. Once the transactions within a batch are executed, the ZK Rollup operator submits a summary of the changes needed for each batch. In addition, the operator is responsible for providing a proof of validity, which is a zero-knowledge proof (ZKP), to ensure the accuracy of the changes made.
- Validity Proof
In an Optimistic Rollup, transactions are initially assumed to be valid and then later challenged if found to be invalid. To establish whether transactions were valid, users would have to challenge a bundle of transactions in optimistic rollups. In optimistic rollups, using fraud proofs to demonstrate transaction validity is useful. The accuracy of transactions in the situation of optimistic rollups depends on game-theoretical incentives.
In ZK Rollup, transactions are verified using zero-knowledge proofs (ZKPs). ZKP is an encryption protocol that allows verifying the correctness of computations without revealing any computational inputs or outputs. This means ZK Rollup can process transactions off-chain while ensuring their validity without compromising network security and privacy. Mathematical proofs can ensure the accuracy of validity proofs in zk-rollups.
- Transaction Finality
Optimistic Rollups require users to wait for a challenge period before withdrawing their funds, leading to a delay in the final confirmation of transactions, which is typically a period of around 7 days. In contrast, ZK Rollups allow fund withdrawal based on the validity proofs, with no waiting period required.
3.2 Transaction Cost
In theory, Rollups can aggregate hundreds of transactions into a single Layer 1 transaction, resulting in potentially hundreds of times savings on gas fees. From a user perspective, low gas fees and fast transaction confirmations are their primary requirements. Since Optimistic Rollups require minimal data to be published and only need to provide transaction proofs in case of challenges, they can offer lower costs. As a result, Optimistic Rollups may achieve better cost efficiency. On the other hand, ZK Rollups incur additional expenses for creating and verifying proofs for different transaction batches, which can lead to higher costs. It’s also worth noting that creating zero-knowledge proofs requires high-end hardware. On-chain verification costs associated with ZK Rollups can also be more expensive.
In practice, there is a noticeable difference in gas fees among various solutions. According to data from L2Fees.info as of October 19th, sending ETH on the Ethereum mainnet costs around $0.46, and swap transactions require approximately $2.31 in gas fees. Gas fees for sending ETH in Layer 2 projects are generally below $0.02.
Figure 6. Layer 2 fees (Source: l2fees.info)
zk Rollup is a strong competitor to Optimistic Rollup, but currently, due to its greater technical complexity, it lags significantly behind in terms of product launches and ecosystem development compared to Optimistic Rollup-based Layer 2 solutions. As a result, Arbitrum and Optimism have a first-mover advantage; they launched earlier, have more funding, collaboration with applications, and a higher number of projects and native applications. In 2023, many ZK projects are launching their mainnets, indicating that ZK technology has matured and stabilized considerably. However, in the current zk Rollup ecosystem, the top 5 ecosystems by Total Value Locked (TVL) are predominantly DEX (Decentralized Exchanges), with a severe lack of native projects and innovative ecosystem projects, such as gaming and social applications.
4. New Narrative：Rollup As A Service
With the gradual growth of some dApps and the expansion of various new applications, especially in the DeFi and gaming sectors, being a standalone dApp is no longer sufficient to meet the project’s pursuit of user experience and profitability. These projects require higher-performance infrastructure to handle large traffic and customized needs. Many applications have begun to adopt the concept of an “Appchain,” such as dYdX. The idea of an “Appchain” became a hot topic in 2022. Different projects can design their dedicated chains customized for their application scenarios and requirements. This allows dApps to have dedicated resources on a single chain, ensuring lower operating costs and higher performance without disconnecting from the broader ecosystem, ultimately providing a better user experience.
For these dApps, there are various options available. They can use the Cosmos SDK to build a dedicated chain, or they can function as a Subchain on networks like BNB Chain or Avalanche. Another option is to develop a Layer 2 chain, which can attract the large user base of Ethereum and achieve good interoperability with existing Layer 2 projects. To enable a dApp to quickly launch a Layer 2 chain, the concept of “RaaS” (Rollup as a Service) was born. This has become a competitive arena for leading Layer 2 projects.
Optimism, Arbitrum, zkSync, and others are trying to extend their L2 technologies and solutions. They aim to provide modular solutions to meet various chain deployment scenarios and requirements, expanding their ecosystems and creating their own superchains. One notable contender in this space is OP Stack, developed by Optimism.
4.1 OP Stack and Superchain
OP Stack is proposed by the development team of Optimism, and it’s a highly scalable and interoperable modular blockchain stack. OP Stack decouples different functional layers and combines them in the form of an API software stack. OP Stack is maintained by the OP Collective, allowing anyone to use Optimistic Rollup to build their own Layer 2 blockchain on Ethereum.
OP Stack achieves the following functions:
- Creating a shared, standardized open-source code repository.
- Simplifying the process of building modular blockchains by enabling rapid deployment of modular blockchains based on the existing OP Stack codebase.
- Allowing developers to easily abstract various components of the blockchain and modify it by inserting different modules (e.g., switching from OP Rollup to ZK Rollup).
Layer 2 projects developed through the OP Stack have formed a superchain ecosystem. Currently, a total of 19 projects have joined or are planning to join the OP Stack superchain ecosystem. These projects span various domains, including exchanges, public chains, clients, NFT, gaming, derivatives, and more. Some of the projects in this ecosystem include opBNB, Zora, Base, Wordcoin, and DeBank. The superchain ecosystem exhibits the following property and advantages:
|Shared L1 blockchain||Provides a total ordering of transactions across all OP Chains.|
|Shared bridge for all OP Chains||Enables OP Chains to have standardized security properties.|
|Cheap OP Chain deployment||Enables deploying and transacting on OP Chains without the high fees of transacting on L1.|
|Configuration options for OP Chains||Enables OP Chains to configure their data availability provider, sequencer address, etc.|
|Secure transactions and cross-chain messages||Enables users to safely migrate assets between OP Chains.|
OP Stack has brought greater possibilities to Optimism. For example, in terms of revenue, only Base alone can bring an additional $4.5 million in annual revenue to the OP treasury. BASE is required to pay 2.5% of its total fees to the Optimism Collective and adhere to Optimism’s “superchain” standards, paving the way for future interoperability. In exchange, BASE, as a member of the Optimism Collective, has a governance role.
4.2 Arbitrum Orbit & ZK Stack
Arbitrum Orbit and L3: The Orbit development framework allows the creation and deployment of L3 on the Arbitrum mainnet. L3 Rollup, also known as Appchains, plays a crucial role in settling transactions on the Arbitrum. They form the foundation for the next stage of Arbitrum’s scaling journey. Orbit is designed to be compatible with the upcoming Arbitrum Stylus upgrade. This compatibility provides developers with the possibility of building dApps using C, C++, and Rust, expanding Arbitrum’s versatility and coverage.
ZK Stack: On the evening of June 26th, zkSync announced the launch of a modular open-source framework called ZK Stack for building customized zkRollups. It aims to empower developers with full autonomy, from the choice of sequencer and data availability mode to defining your own tokenomics. It is expected to go live before the end of the year.
In the existing RaaS (Rollup As A Service) projects, most of them are primarily based on Optimistic Rollup. The main reasons for this are:
- Ecosystem always comes first: RaaS based on Optimistic Rollup offers better compatibility, significantly lowering the barriers for projects to migrate and develop quickly. This enables more projects to deploy rapidly, build a thriving ecosystem, and gain a first-mover advantage.
- Lower barriers, less reliance on computing power: RaaS based on Optimism also validates transaction validity through fraud prevention, which places lower demands on machine performance and reserves in terms of computing power. This is a limiting factor for many RaaS projects that cannot start.
- Easier to scale: RaaS based on Optimism has lower development barriers compared to ZK (Zero-Knowledge) RaaS. While ZK RaaS focuses on performance and more low-level customization, it requires deeper involvement from providers. Additionally, due to the computing power required for generating ZK proofs, large-scale deployment of ZK RaaS is challenging, unlike Optimism RaaS.
While Optimism Rollup has a clear advantage in ecosystem development, RaaS based on ZK (Zero-Knowledge) also offers advantages in terms of performance and security. In the short term, the ecosystem advantage of RaaS based on Optimism is undeniable. However, from a long-term perspective and considering the demands and value creation, it is likely that RaaS based on ZK will gain a larger market share in the future.
5. Challenges and Opportunities
Arbitrum’s airdrop has ignited the Layer 2 frenzy, but behind the FOMO, it has also raised a series of issues:
- Speculators have become overly enthusiastic, sometimes overlooking the project’s actual development and the technological advancements in the blockchain space. In comparison to the AI industry, the wealth creation effect has been too pronounced, which means users might not fully benefit from the technical advancements the products offer. This situation isn’t conducive to the industry’s long-term growth.
- Despite being in a bear market, there has been increased competition and a tendency for market participants to engage in zero-sum games.
- Expectations for Layer 2 solutions have far surpassed those for Layer 1 blockchains. The Ethereum ecosystem has accumulated a significant amount of capital, and the narrative and opportunities have shifted to Layer 2 solutions.
Many Layer 2 projects have yet to issue tokens, and their wealth creation potential may continue into the next bull market, further driving attention from users and investors. However, experimental and early-stage aspects still persist, and Layer 2 solutions come with certain risks and issues:
- Centralization Risks: These scaling solutions are in their early decentralized stages and carry inherent centralization risks. Layer 2 solutions make trade-offs in decentralization, moving transactions and data off-chain, which are then processed by sequencers who bundle transactions and upload them to the mainnet. Currently, only a single entity operates as a “sequencer,” which introduces centralization risks. The Arbitrum network has experienced sequencer issues leading to widespread downtime.
- Fragmented Liquidity: This issue exists in both Layer1 and Layer 2 networks. With the increasing number of Layer 2 projects using various scaling approaches, composability between dapps is constrained, leading to fragmentation and liquidity split across Ethereum and different Layer 2 solutions. This raises liquidity costs for projects.
- Limited Ecosystem: While Layer 2 projects theoretically have high TPS, the practical maximum is around 30. This is because current applications don’t require such high performance. Layer 2 lacks a killer app that can truly leverage its infrastructure capabilities.
- Data Availability: Many zk rollup projects use a hybrid approach to address data availability, offering both a traditional on-chain data storage rollup version and an off-chain data storage validium version. Some on-chain infrastructure providers, such as Celestia, are now also offering data availability services in a more decentralized manner, which may become the preferred solution for Layer 2.
- Decentralized Sequencers: Decentralized sequencers are one of the solutions to enhance the security and fairness of Layer 2. Some projects (Espresso, Astria, and Radius) are already developing shared sequencers.
- The implementation of EIP-4844 and Danksharding will further reduce the cost of L2 rollups, promoting the adoption of Layer 2 projects.
- Increasing demand for interoperability protocols to maintain the composability and liquidity of the Ethereum ecosystem.
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HTX Ventures, the global investment division of HTX, integrates investment, incubation, and research to identify the best and brightest teams worldwide.
With a decade-long history as an industry pioneer, HTX Ventures excels at identifying cutting-edge technologies and emerging business models within the sector. To foster growth within the blockchain ecosystem, we provide comprehensive support to projects, including financing, resources, and strategic advice.