Layer-2 Ecosystem Explained: Arbitrum, Optimism, Base, zkSync & L2 Market Share

Key Takeaways

• The Layer-2 ecosystem is the network of rollups, scaling platforms, bridges, apps, sequencers, data layers, and developer stacks built around Ethereum scaling.
• Arbitrum, Optimism, Base, zkSync, Starknet, Scroll, Blast, and Mantle represent different approaches to L2 growth, liquidity, users, and infrastructure.
• L2 market share can be measured by TVL/TVS, active users, transactions, fees, app activity, developer adoption, and ecosystem depth.
• Arbitrum is often viewed as a DeFi and liquidity-focused L2, while Base has grown strongly through consumer apps, Coinbase distribution, and OP Stack alignment.
• Optimism is not only one chain; it is also the foundation for the Superchain strategy through OP Stack.
• zkSync, Starknet, and Scroll represent important ZK rollup ecosystems, each with different technical assumptions and developer positioning.
• Orbit, Superchain, and app-specific L2s show that the L2 market is moving from a few general-purpose networks toward many customizable execution environments.

1. What is the Layer-2 ecosystem?

The Layer-2 ecosystem is the collection of blockchain networks, applications, tools, bridges, sequencers, rollup stacks, infrastructure providers, and developer communities that scale Ethereum by moving execution away from Ethereum Layer 1.

In the early Ethereum market, most activity happened directly on L1. Users traded on Ethereum, minted NFTs on Ethereum, borrowed and lent on Ethereum, and paid Ethereum gas fees for almost everything. As demand grew, Ethereum L1 became expensive and congested. Layer-2 networks emerged to solve this problem.

A Layer-2 network usually processes transactions off Ethereum L1 and posts data, proofs, or state commitments back to Ethereum. This allows users to access cheaper and faster transactions while still relying on Ethereum for settlement or security in different ways.

The Layer-2 ecosystem includes:

General-purpose rollups such as Arbitrum, Optimism, Base, zkSync, Starknet, Scroll, Blast, and Mantle.

Rollup frameworks such as OP Stack, Arbitrum Orbit, Polygon CDK, ZK Stack, and Starknet appchain tooling.

Bridges and interoperability layers that move assets and messages across L2s.

DeFi protocols, NFT platforms, games, social apps, and consumer applications deployed on L2s.

Sequencers, provers, data availability systems, RPC providers, indexers, wallets, and explorers.

Ecosystem incentive programs, governance systems, grants, and developer communities.

The Layer-2 ecosystem is no longer just a scaling category. It is becoming the execution layer of Ethereum’s broader economy.

2. Why the Layer-2 ecosystem matters

The Layer-2 ecosystem matters because Ethereum’s future depends heavily on rollup-based scaling.

Ethereum L1 provides security, settlement, neutrality, and high-value finality. But many user activities require lower fees and faster confirmation times than L1 can offer directly. L2s make Ethereum usable for more people and more applications.

Layer-2 networks matter for several reasons.

First, they reduce transaction costs. This allows smaller users, consumer apps, games, payments, and high-frequency DeFi interactions to exist more easily.

Second, they increase throughput. More transactions can happen without forcing Ethereum L1 to process everything directly.

Third, they expand application design. Developers can build apps that would be too expensive or slow on L1.

Fourth, they create specialized ecosystems. Some L2s focus on DeFi, others on consumer apps, gaming, identity, social, payments, or institutional settlement.

Fifth, they change Ethereum’s economic model. Fees, blob demand, sequencer revenue, MEV, and L2 settlement activity all become part of the Ethereum scaling economy.

Sixth, they create competition inside the Ethereum ecosystem. L2s compete for liquidity, apps, developers, wallets, bridges, and users.

The Layer-2 ecosystem is therefore not only technical infrastructure. It is the market structure of Ethereum execution.

3. Arbitrum

Arbitrum is one of the largest and most established Ethereum Layer-2 ecosystems.

It is best known for Arbitrum One, an optimistic rollup that has attracted deep DeFi liquidity, major protocols, derivatives platforms, DEX activity, and active governance. Arbitrum’s strength comes from being early, EVM-compatible, liquidity-rich, and developer-friendly.

Arbitrum has often been positioned as a DeFi-heavy L2. Major applications across trading, lending, perpetuals, structured products, gaming, and infrastructure have deployed there. The network’s liquidity depth makes it attractive for power users and protocols that need strong composability.

Arbitrum’s ecosystem is not limited to one chain. Arbitrum Orbit allows teams to launch custom chains using Arbitrum technology. These can be app-specific chains, gaming chains, enterprise environments, or specialized execution networks.

Arbitrum matters because it shows one important L2 strategy: build a strong general-purpose rollup first, then expand into a broader ecosystem of customizable chains.

Key strengths:

Deep DeFi liquidity

Strong developer adoption

Large user base

Mature ecosystem

Orbit appchain expansion

Key risks:

Competition from Base and other L2s

Sequencer centralization assumptions

Governance complexity

Liquidity fragmentation across Orbit chains

Bridge and upgrade risks

4. Optimism

Optimism is both a Layer-2 network and the foundation of a broader scaling ecosystem.

OP Mainnet is an optimistic rollup that helped popularize the OP Stack. But Optimism’s larger strategy is the Superchain: a network of L2s built using shared infrastructure, governance principles, and technical standards.

Optimism is important because it shifted the market’s view of L2s. Instead of treating each L2 as an isolated network, Optimism promotes the idea of many OP Stack chains connected through a shared ecosystem.

The OP Stack is described in Optimism documentation as a standardized, shared, open-source development stack for building production-ready Layer-2 blockchains. This makes it possible for teams to launch their own chains while benefiting from common infrastructure and alignment with Optimism’s roadmap.

Optimism’s strategy is less about only competing as one chain and more about becoming a chain factory and coordination layer for many chains.

Key strengths:

OP Stack adoption

Superchain strategy

Strong governance and public goods narrative

Developer tooling

Ecosystem partnerships

Key risks:

Competition among OP Stack chains

Value capture uncertainty

Fragmented liquidity across the Superchain

Sequencer and governance centralization concerns

Dependence on ecosystem coordination

5. Base

Base is an Ethereum Layer-2 network developed by Coinbase and built on the OP Stack.

Base has become one of the most important L2s because it combines Ethereum alignment with Coinbase distribution. Coinbase brings a large user base, institutional relationships, fiat on/off ramps, wallet infrastructure, and brand recognition. This gives Base a strong advantage in onboarding users from centralized platforms into onchain applications.

Base has grown especially fast in consumer apps, social applications, memecoins, payments experiments, creator tools, and retail-friendly DeFi. It is also part of the broader OP Stack and Superchain direction.

Base’s importance comes from its distribution model. Many L2s compete mainly through incentives or technical features. Base has the advantage of being connected to one of the largest crypto exchanges and consumer platforms in the United States.

Key strengths:

Coinbase distribution

OP Stack compatibility

Strong consumer app momentum

Fast user growth

Developer and wallet ecosystem

Key risks:

Centralized sequencing and Coinbase dependency

Regulatory exposure

Consumer speculation cycles

Liquidity quality vs transaction volume

Competition from other OP Stack chains

6. zkSync

zkSync is a ZK rollup ecosystem developed by Matter Labs.

Its core idea is to scale Ethereum through validity proofs rather than fraud proofs. ZK rollups generate cryptographic proofs that verify transaction execution. This can support stronger finality assumptions and a different security model from optimistic rollups.

zkSync has positioned itself around ZK technology, account abstraction, developer experience, and the ZK Stack. The ZK Stack is designed to support custom ZK-powered chains and ecosystem expansion.

zkSync matters because it represents one of the major attempts to build a general-purpose ZK rollup ecosystem for Ethereum. While optimistic rollups gained early adoption because of easier EVM compatibility, ZK rollups are often viewed as a long-term scaling path due to validity proofs.

Key strengths:

ZK rollup design

Validity proof model

Account abstraction focus

ZK Stack ecosystem

Long-term technical potential

Key risks:

ZK infrastructure complexity

Developer adoption competition

Liquidity depth compared with larger optimistic rollups

Proof system maturity

Ecosystem differentiation

7. Starknet

Starknet is a ZK rollup ecosystem built around STARK proofs and the Cairo programming language.

Unlike some EVM-equivalent L2s, Starknet takes a more distinct technical path. Cairo is designed for provable computation, and Starknet’s architecture is deeply connected to STARK-based scaling.

Starknet is important because it represents a more specialized ZK ecosystem. It is not simply trying to copy Ethereum execution at lower cost. It is building around a proof-friendly execution environment.

This gives Starknet technical advantages but also creates adoption challenges. Developers may need to learn new tools, languages, and design patterns. The ecosystem’s success depends on whether this technical differentiation can translate into better applications, stronger performance, and developer loyalty.

Key strengths:

STARK proof technology

Cairo ecosystem

Technical differentiation

Strong research orientation

Long-term ZK scaling potential

Key risks:

Developer learning curve

Smaller liquidity base than leading L2s

Competition from EVM-compatible ZK rollups

User experience complexity

Ecosystem maturity

8. Scroll

Scroll is a ZK rollup focused on EVM compatibility and Ethereum alignment.

Scroll’s value proposition is to bring ZK scaling to Ethereum while preserving a familiar developer environment. This matters because developer migration is easier when smart contracts, tooling, and application patterns remain close to Ethereum.

Scroll competes in the ZK rollup category, but its positioning is different from Starknet. While Starknet emphasizes a distinct proof-native stack, Scroll emphasizes Ethereum compatibility and easier developer adoption.

Scroll is important because it represents a practical path for ZK adoption: make ZK rollups feel as close to Ethereum as possible.

Key strengths:

EVM compatibility

Ethereum-aligned positioning

ZK rollup architecture

Developer familiarity

Potential DeFi and application migration

Key risks:

Competition with zkSync and other ZK EVMs

Liquidity bootstrapping

Proof cost and infrastructure complexity

Ecosystem differentiation

User acquisition

9. Blast

Blast is a Layer-2 network that gained attention through native yield and incentive-driven growth.

Its early positioning focused on giving users yield on ETH and stablecoin balances, creating a different user acquisition model from traditional rollups. Instead of competing only on fees, Blast used financial incentives and yield mechanics to attract deposits and activity.

Blast matters because it shows how L2 competition is not purely technical. Liquidity incentives, native yield, airdrop expectations, and ecosystem campaigns can rapidly change market share.

However, incentive-driven growth can be fragile. TVL can rise quickly when users expect rewards, but activity quality may be harder to evaluate. The key question is whether liquidity remains after incentives decline and whether the ecosystem can develop durable applications.

Key strengths:

Strong initial liquidity attraction

Native yield narrative

Retail attention

Application incentive ecosystem

Key risks:

Incentive dependency

TVL stickiness

Speculative user behavior

Differentiation beyond yield

Sustainability of economic model

10. Mantle

Mantle is an Ethereum Layer-2 ecosystem associated with modular blockchain architecture and strong treasury-backed ecosystem development.

Mantle has positioned itself around modular design, ecosystem incentives, liquid staking connections, and capital deployment. It has also been connected to broader BitDAO/Mantle governance and treasury resources.

Mantle matters because it shows another L2 strategy: use capital, ecosystem incentives, modular infrastructure, and strategic integrations to compete for users and developers.

Mantle’s growth depends on whether it can convert treasury resources and incentives into durable applications, liquidity, and user activity.

Key strengths:

Treasury-backed ecosystem

Modular infrastructure direction

Incentive capacity

DeFi and liquid staking integrations

Strategic ecosystem development

Key risks:

Competition for developers

Incentive sustainability

Liquidity depth

Differentiation from larger L2s

User retention after campaigns

11. L2 market share

Layer-2 market share can be measured in several ways. There is no single perfect metric.

The most common measures include:

TVL or TVS: how much value is locked or secured on the network.

Active users: how many addresses interact with the network.

Transactions: how much activity the chain processes.

Fees and revenue: how much users pay and how much the network captures.

DEX volume: how much trading happens on the network.

Stablecoin supply: how much stablecoin liquidity exists.

Developer activity: how many applications and teams are building.

Bridge inflows: how much capital moves into the network.

Retention: whether users return after incentives end.

Arbitrum has historically led in DeFi liquidity and total value. Base has become a major competitor through user activity, consumer apps, and Coinbase distribution. Optimism remains important through OP Mainnet and the Superchain strategy. zkSync, Starknet, and Scroll represent the ZK rollup category. Blast and Mantle show how incentive design and capital strategies can create fast growth.

The key point: TVL alone is not enough.

A chain can have high TVL but low real users. Another can have high transactions but low value. Another can have many users due to incentives but weak retention. A strong L2 ecosystem should show a combination of liquidity, users, applications, transactions, developer activity, and sustainable revenue.

12. TVL, users, and transactions

TVL, users, and transactions are the three most common ways to compare Layer-2 networks, but each has limitations.

TVL measures capital. It shows how much value is deposited in protocols or secured on the network. It is useful for DeFi depth, but it can be inflated by incentives, recursive deposits, or large holders.

Users measure adoption. Active addresses show how many wallets interact with the chain, but one user can control many addresses. Bot activity, airdrop farming, and low-value interactions can distort the picture.

Transactions measure activity. High transaction count can indicate usage, but it can also reflect spam, bots, low-value activity, or application design differences.

A better L2 analysis combines multiple metrics:

TVL/TVS for value secured

Stablecoin supply for liquidity quality

DEX volume for trading activity

Daily active users for adoption

Transactions for throughput

Fees for willingness to pay

Retention for ecosystem stickiness

App diversity for sustainability

Bridge flows for capital movement

Revenue for economic viability

For Cryptothreads, the best framing is to treat L2 market share as a multi-dimensional market structure question, not a simple ranking table.

13. Superchain

The Superchain is Optimism’s vision for a network of OP Stack chains that share common infrastructure, standards, and ecosystem alignment.

Instead of one L2 absorbing all users, the Superchain model allows many chains to exist for different use cases while still being connected through shared technology and governance principles.

Examples of OP Stack chains include OP Mainnet, Base, and other chains building with the OP Stack.

The Superchain matters because it changes the L2 market from single-chain competition into stack-level competition. If many successful chains use the OP Stack, Optimism’s ecosystem influence can grow even if OP Mainnet itself is not always the largest chain by TVL.

The key questions for the Superchain are:

Can chains share liquidity more efficiently?

Can interoperability become seamless?

Can security and governance be coordinated?

Can value accrue back to the Optimism ecosystem?

Can the user experience feel unified?

The Superchain is one of the strongest examples of the “many L2s, shared stack” thesis.

14. Arbitrum Orbit

Arbitrum Orbit is Arbitrum’s framework for launching custom chains using Arbitrum technology.

Orbit chains can be designed for specific applications, communities, games, institutions, or ecosystems. This allows teams to customize execution, fees, governance, data availability, and network parameters while staying connected to Arbitrum’s broader technology stack.

Orbit matters because it shows how the L2 market is becoming modular. Instead of every application deploying on the same shared rollup, teams can launch dedicated environments optimized for their own needs.

Use cases for Orbit-style chains include:

Gaming chains

Perpetual trading chains

App-specific DeFi networks

Enterprise settlement environments

Community chains

High-throughput consumer apps

Custom fee models

Application-specific governance

The risk is fragmentation. More chains mean more bridges, more liquidity splits, more security assumptions, and more user complexity. The opportunity is specialization. Apps can get their own execution environment without building a full L1 from scratch.

15. App-specific L2s

App-specific L2s are Layer-2 networks designed around a specific application, protocol, industry, or use case.

Instead of deploying an app on a general-purpose L2, a team launches its own chain. This gives the app more control over fees, sequencer rules, MEV, governance, data availability, upgrade paths, and user experience.

App-specific L2s can be useful for:

Games

Derivatives exchanges

Social networks

Payment systems

NFT platforms

Enterprise workflows

AI agent economies

High-frequency trading apps

Consumer apps with high transaction volume

The app-specific L2 trend is part of a broader shift from monolithic chains to modular execution. The future may include many specialized chains connected through shared settlement, shared sequencing, bridges, interoperability layers, or rollup frameworks.

The main challenge is liquidity. General-purpose L2s benefit from shared liquidity and composability. App-specific L2s may improve performance but risk becoming isolated unless interoperability improves.

16. Market implications

The Layer-2 ecosystem has major market implications.

First, Ethereum is becoming a settlement layer for many execution environments. This changes how Ethereum captures value and how users experience Ethereum.

Second, L2 competition is becoming stack competition. OP Stack, Arbitrum Orbit, ZK Stack, Polygon CDK, Starknet tooling, and other frameworks compete to become the foundation for many chains.

Third, liquidity is fragmenting across networks. This creates opportunities for bridges, interoperability protocols, cross-chain DEXs, intent systems, and shared sequencing.

Fourth, user acquisition is changing. L2s compete through airdrops, incentives, apps, wallets, exchange distribution, developer grants, and ecosystem narratives.

Fifth, app-specific L2s may reduce pressure on general-purpose chains but increase complexity.

Sixth, L2 metrics must be interpreted carefully. TVL, users, and transactions can tell different stories.

Seventh, the L2 ecosystem may become the main battleground between Ethereum and alternative Layer-1 ecosystems. If Ethereum L2s can offer low fees, strong apps, and seamless UX, Ethereum can scale without sacrificing L1 security.

17. Risks and limitations

The Layer-2 ecosystem still has several risks.

The first is liquidity fragmentation. Users and capital are spread across many chains, making liquidity harder to coordinate.

The second is bridge risk. Bridges are critical to moving assets across L2s, but they introduce security and UX risk.

The third is sequencer centralization. Many L2s still depend on centralized sequencers.

The fourth is upgrade risk. Some L2s rely on multisigs or governance processes that can change contracts.

The fifth is incentive distortion. Airdrops and rewards can inflate TVL, users, or transactions without creating durable adoption.

The sixth is metric confusion. A chain may appear successful by one metric while weak by another.

The seventh is interoperability risk. Without better cross-L2 communication, Ethereum’s L2 ecosystem can feel fragmented to users.

The eighth is value capture uncertainty. It is still unclear how much value accrues to L2 tokens, ETH, sequencers, app tokens, or infrastructure providers.

Layer-2s are essential to scaling, but they are not a finished product. The ecosystem still needs better security, decentralization, interoperability, and user experience.

Conclusion

The Layer-2 ecosystem is becoming the execution layer of Ethereum. Arbitrum, Optimism, Base, zkSync, Starknet, Scroll, Blast, Mantle, and other L2s each represent different strategies for scaling users, liquidity, applications, and developer ecosystems.

Arbitrum leads with DeFi depth and liquidity. Optimism expands through OP Stack and the Superchain. Base grows through Coinbase distribution and consumer applications. zkSync, Starknet, and Scroll push the ZK rollup category forward. Blast and Mantle show how incentives, yield, treasury resources, and ecosystem design can shape L2 competition.

The most important shift is that Layer-2 is no longer a single category. It is becoming a multi-layer market of general-purpose rollups, stack ecosystems, app-specific chains, shared infrastructure, sequencer markets, bridges, and specialized execution environments.

To analyze the L2 ecosystem properly, market share should not be measured only by TVL. A stronger framework includes TVL, users, transactions, fees, stablecoin supply, DEX volume, developer activity, retention, and security assumptions.

As Ethereum scales, the key question is not only which L2 is biggest today. The deeper question is which L2 ecosystems can build durable liquidity, real users, sustainable applications, decentralized infrastructure, and seamless interoperability across the next phase of onchain adoption.

Sources / References

1. L2BEAT — The State of the Layer Two Ecosystem
   https://l2beat.com/
   Use for L2 TVS, market share, risk analysis, project comparisons, rollup stages, and Ethereum Layer-2 ecosystem tracking.
2. DeFiLlama — Chains
   https://defillama.com/chains
   Use for TVL across Arbitrum, Optimism, Base, zkSync, Starknet, Scroll, Blast, Mantle, and other chains.
3. Artemis — Blockchain Activity Monitor
   https://app.artemis.xyz/
   Use for active addresses, transactions, fees, stablecoin supply, DEX volume, and chain-level activity metrics.
4. Optimism Docs — OP Stack
   https://docs.optimism.io/op-stack/introduction/op-stack
   Use for OP Stack, Superchain architecture, production-ready Layer-2 deployment, and modular L2 development.
5. Arbitrum Docs — Arbitrum Orbit
   https://docs.arbitrum.io/launch-arbitrum-chain/arbitrum-orbit-gentle-introduction
   Use for Orbit chains, custom L2/L3 deployments, app-specific chains, and Arbitrum ecosystem expansion.
6. zkSync Docs — ZK Stack
   https://docs.zksync.io/zk-stack
   Use for ZK Stack, custom ZK chains, zkSync ecosystem expansion, and app-specific ZK rollup infrastructure.
7. Starknet Docs — Starknet Documentation
   https://docs.starknet.io/
   Use for Starknet architecture, Cairo, STARK proofs, account abstraction, and ZK rollup ecosystem design.
8. Scroll Docs — Scroll Documentation
   https://docs.scroll.io/
   Use for Scroll architecture, ZK rollup design, Ethereum compatibility, bridge mechanics, and developer onboarding.