The Future of ZK-Rollup Architecture: Modular vs. Monolithic State

Integrated chains like zkSync Era and Starknet bundle execution, settlement, and data availability (DA) into a single, vertically integrated stack. This creates a performance ceiling and vendor lock-in.

• State Growth forces expensive hardware upgrades for all nodes.
• Innovation Silos prevent swapping components (e.g., using Celestia for DA).
• Protocol Risk is concentrated; a bug in one layer can halt the entire chain.

Projects like Fuel and dYmension decouple execution from settlement and consensus. The rollup becomes a sovereign state machine that posts proofs and data to a base layer, enabling radical specialization.

• Unbundled Innovation allows mixing EigenDA, Celestia, and any prover.
• Sovereign Forks enable governance-led upgrades without base-layer permission.
• Local Fee Markets prevent congestion from one app spiking costs for all.

StarkEx and zkSync's Volition model offer a pragmatic middle ground. Apps can choose between ZK-rollup (secure) or Validium (scalable) modes for their data, trading off security for cost.

• Cost Control: Move stablecoin swaps to Validium (~$0.001 tx), keep NFT mints on rollup.
• Security Flexibility: Critical state uses Ethereum DA; disposable data uses a committee.
• Proven Adoption: Powers dYdX, ImmutableX, and Sorare with $1B+ combined TVL.

Monolithic chains are fighting back with architectural overhauls. Starknet's parallel execution and zkSync's upcoming elastic chains aim to simulate modular benefits within a unified environment.

• State Sharding allows horizontal scaling without fracturing composability.
• Async Composability uses proofs for cross-shard communication, akin to layerzero.
• Developer Simplicity retains a single operational and security model, unlike the modular "DIY" approach.

Modular designs inherit security from the weakest link in their stack (e.g., a data availability committee). Monolithic designs inherit it from their own, more auditable codebase. This is the core tension.

• Modular Risk: Ethereum security for settlement, but Celestia security for data.
• Monolithic Audit Surface: One large codebase is harder to verify but has fewer integration bugs.
• Economic Security: A monolithic chain's native token captures all value; a modular stack's value leaks to external providers.

The ultimate modular vision, championed by Polygon zkEVM and Espresso Systems, involves a shared prover network that batches proofs for multiple rollups. This turns ZK-proof generation into a commodity market.

• Cost Sharing: 100+ chains share fixed proving costs, driving marginal cost to near zero.
• Native Interoperability: Atomic cross-rollup transactions secured by a single proof.
• Prover Decentralization: Specialized hardware operators compete in a free market, unlike today's centralized prover services.

Traditional ZK-rollups like zkSync Era and Starknet manage everything—execution, settlement, data availability—in one vertically integrated stack. This creates vendor lock-in and stifles innovation at individual layers.\n- Inflexible Tech Stack: Can't swap out a faster prover or a cheaper DA layer.\n- Centralized Roadmap: Protocol upgrades are monolithic, slowing iteration.\n- High Integration Cost: New apps must build for one specific environment.

Projects like Celestia, EigenDA, and Avail enable a modular ZK-rollup by providing pluggable Data Availability. This allows rollups to specialize. zkSync's ZK Stack and Polygon CDK are frameworks embracing this.\n- Best-in-Class Components: Choose Espresso for sequencing, Risc Zero for proving.\n- Atomic Composability: Shared settlement layers (e.g., Layer N) enable cross-rollup liquidity.\n- Economic Escape Hatch: Migrate to a cheaper DA layer without a hard fork.

Monolithic architectures argue that tight integration is necessary for maximal performance. Deep optimization across the stack can yield superior throughput and lower latency than modular assemblies.\n- Vertical Optimization: Co-design the VM, prover, and DA for ~500ms finality.\n- Simpler Security Model: One audit surface versus N interdependent modules.\n- Faster Time-to-Market: No need to integrate and test disparate, moving parts.

The sequencer is the new battleground. Shared sequencer networks like Astria and Espresso decouple ordering from execution, creating a neutral marketplace for block space. This is a modular win.\n- MEV Resistance: Proposer-Builder-Separation (PBS) models can be enforced.\n- Atomic Cross-Rollup Bundles: Users can trade on Uniswap on Rollup A and Curve on Rollup B in one tx.\n- Redundancy: No single rollup operator can censor transactions.

StarkEx's Volition and zkSync's Validium mode let applications choose per-transaction between a rollup (data on L1) or validium (data off-chain). This is a hybrid approach that pragmatically addresses cost.\n- Cost Control: Sensitive to $10B+ TVL DeFi apps needing cheap trades.\n- Security Spectrum: From Ethereum-level security to higher-throughput, trusted setups.\n- App-Specific Chains: A gaming validium and a DeFi rollup can interoperate.

The economic and innovation pressures favor modularity long-term. However, monolithic stacks will dominate the ~2-3 year horizon due to maturity and performance. The winner will be the stack that best hides complexity from developers.\n- Endgame: A modular superchain with monolithic-grade UX.\n- Key Metric: Developer migration from EVM L1s to modular L2 frameworks.\n- Risk: Fragmentation liquidity across hundreds of rollups.

Modular ZK-rollups are only as secure as their chosen DA layer. A compromised or censored DA layer (e.g., Celestia, EigenDA) breaks finality for the entire rollup. This creates systemic risk concentrated in a few DA providers.

• Risk: Single point of failure for hundreds of sovereign chains.
• Trigger: DA layer downtime or malicious data withholding.
• Mitigation: Multi-DA clients (like Near's DAC) or fallback to Ethereum DA, which negates cost savings.

Chains like Monad or Sei that optimize for monolithic execution create walled gardens. Achieving secure, low-latency cross-chain communication with ZK-rollups becomes a nightmare, stifling composability.

• Problem: No native, trust-minimized bridge to Ethereum/ZK-rollup ecosystems.
• Consequence: Liquidity fragmentation and reliance on risky third-party bridges (e.g., LayerZero, Wormhole).
• Irony: Recreates the very interoperability problem L2s were meant to solve.

The race for faster provers (e.g., RiscZero, Succinct) creates hardware oligopolies. If proof generation is too expensive or centralized, it becomes a cartel-controlled bottleneck, undermining decentralization.

• Bottleneck: Specialized hardware (GPU/FPGA) required for competitive proving times.
• Economic Risk: Prover costs could eclipse L1 gas fees, making ZK-rollups economically non-viable.
• Who it hurts: Smaller chains and app-specific rollups the most.

Projects like Espresso and Astria promise decentralized sequencing as a service. However, they introduce a new consensus layer, adding latency and creating a liveness dependency separate from the DA and execution layers.

• New Trust Assumption: You must trust the sequencer set's liveness and honesty.
• MEV Redistribution: Does not eliminate MEV; just shifts it to a different set of actors.
• Failure Mode: If the shared sequencer fails, all connected rollups lose transaction ordering.

Sovereign rollups (e.g., using Rollkit) lack the security of Ethereum-settled L2s. They must bootstrap their own validator sets, bridges, and governance from zero—a massive coordination problem most projects will fail at.

• Reality: Most teams cannot replicate the security of Ethereum's validator set.
• Result: A landscape of insecure, illiquid chains vulnerable to 51% attacks.
• Historical Parallel: The 2017 ICO boom of low-security chains.

Splitting state across DA, execution, settlement, and proving layers multiplies the attack surface. A bug in any one component (e.g., a fraud proof system in an OP-stack rollup, a ZK verifier) can compromise the whole system.

• Integration Risk: More moving parts = more integration bugs and harder audits.
• Coordination Failure: Layers may upgrade out of sync, causing chain splits.
• Winner: Monolithic chains have a simpler, more auditable security model.

Legacy rollups like zkSync Era and Starknet treat state as a single, global database. This creates a hard ceiling on throughput and forces all apps to compete for the same resources.\n- Constrained TPS: Theoretical limits of ~100-200 TPS per chain.\n- Congestion Spillover: One popular NFT mint can slow down all DeFi transactions.\n- Upgrade Inertia: Protocol upgrades require a hard fork of the entire system.

Architectures like zkSync Hyperchains and Starknet Appchains decompose state into parallel, application-specific instances. Each app-chain has its own execution environment and can settle proofs to a shared settlement layer like Celestia or EigenDA.\n- Horizontal Scaling: 1000+ TPS achievable via parallel chains.\n- Customizability: Each chain can have its own VM, fee token, and governance.\n- Independent Execution: Failure or congestion in one app-chain is isolated.

In a modular future, the monolithic sequencer is replaced by a decentralized network of verifiers. Projects like Espresso Systems and Astria are building shared sequencer sets that provide censorship resistance and fast finality. The security model shifts from trusting a single operator to trusting the cryptographic proof.\n- Censorship Resistance: No single entity can order or censor transactions.\n- Fast Finality: ~2 second finality via proof publication, not block confirmations.\n- Shared Security: Verifier sets can be reused across multiple app-chains.

Cross-chain communication in a modular state world is not about token bridges but about shared proof verification. A proof generated on one app-chain can be verified on another via the base settlement layer (e.g., Ethereum). This creates native composability without introducing new trust assumptions.\n- Trust-Minimized Comms: No external bridge validators or oracles required.\n- Atomic Cross-Chain TXs: Enabled by shared sequencers like Espresso.\n- Unified Liquidity: Protocols like Uniswap can deploy a single AMM across many app-chains.

The largest value accrual will be in the infrastructure layers that enable modular state. This includes DA layers (Celestia, EigenDA), shared sequencers (Espresso, Astria), and proving marketplaces. Building another monolithic L2 is a depreciating strategy.\n- Infrastructure Moats: DA and sequencing are winner-take-most markets.\n- Protocol Revenue: Fees from proof settlement and data availability are recurring.\n- Developer Capture: The layer that attracts the most builders captures the most value.

The distinction between zkSync, Starknet, Polygon zkEVM, and Scroll will blur as they all evolve into ZK settlement layers for thousands of modular app-chains. Interoperability will be achieved through recursive proofs and standardized proof systems. The winning settlement layer will be the one with the most decentralized prover network.\n- Recursive Proofs: Enables aggregation of proofs from many chains into one.\n- Standardized VMs: WASM and EVM compatibility will be table stakes.\n- Prover Decentralization: The key metric for long-term security and liveness.