How to Architect a dApp for Rollups: Arbitrum, Optimism, zkSync

introduction

DEVELOPER GUIDE

How to Architect a Rollup-Centric Application

A practical guide to designing and building applications that leverage the scalability and security of rollup technology.

Rollup-centric architecture shifts the application's primary execution layer from a monolithic Layer 1 (L1) blockchain to a dedicated Layer 2 (L2) rollup. Instead of deploying a smart contract directly to Ethereum mainnet, you deploy it to a rollup like Arbitrum, Optimism, or a custom OP Stack or Arbitrum Orbit chain. The core logic and state transitions of your application happen on this high-throughput, low-cost L2. The L1 (typically Ethereum) then serves as a secure data availability and settlement layer, where rollup transaction data is posted and state roots are finalized. This separation of concerns is the foundation of rollup-centric design.

The first architectural decision is choosing your rollup's data availability (DA) solution. This determines where the transaction data necessary to reconstruct the L2 state is stored. Using Ethereum for DA (as Ethereum L2s do) offers the highest security but incurs higher costs. Alternatives like Celestia, EigenDA, or Avail provide lower-cost, high-throughput DA layers, which is a core feature of modular blockchain designs. Your choice directly impacts security assumptions, cost structure, and interoperability. For maximum security with a user base comfortable with Ethereum-level fees, an Ethereum L2 is ideal. For applications prioritizing ultra-low transaction costs, a rollup with an external DA layer may be preferable.

Your application's smart contracts must be designed with the rollup environment in mind. While Solidity/Vyper development is similar to L1, you must account for key differences: gas costs are primarily for L1 data posting (measured in L1Gas), certain opcodes may have modified behavior, and block times/gas limits differ. Furthermore, you should architect for cross-chain messaging. Use the native bridge's messaging system (like ArbSys or L2CrossDomainMessenger) for secure L1<>L2 communication for administrative functions (e.g., upgrading contracts, managing treasuries). For user-facing interactions, integrate a cross-chain messaging protocol like LayerZero, Wormhole, or Hyperlane to connect your rollup to other chains in your ecosystem.

A critical component is the sequencer, the node responsible for ordering transactions. When using a managed rollup (like Base), the sequencer is operated by the rollup provider. If you deploy a custom rollup (e.g., with OP Stack), you operate your own. The sequencer provides instant transaction confirmations and can offer features like MEV protection. Architecturally, you may need to run a full node or an RPC endpoint for your application to have low-latency access to chain data. For decentralization, you can participate in or design a decentralized sequencer set, using a consensus mechanism like PoS to order transactions, moving beyond a single trusted operator.

Finally, you must plan the user onboarding and asset flow. Users need a wallet configured for your rollup's RPC endpoint. They require bridged assets to pay for gas and interact. Facilitate this by integrating a bridge UI (like the official rollup bridge) or an aggregator like Socket or Li.Fi. Your front-end should dynamically detect the user's network and prompt them to switch or bridge funds. Consider using account abstraction (ERC-4337) via providers like Biconomy or Stackup to sponsor gas fees or enable social logins, dramatically improving the user experience specific to the rollup environment where gas fees are already low.

prerequisites

PREREQUISITES FOR ROLLUP DEVELOPMENT

How to Architect a Rollup-Centric Application

This guide outlines the core architectural decisions and technical prerequisites for building an application designed to run on a rollup.

Architecting for a rollup requires a fundamental shift from traditional smart contract development. The primary consideration is state management. On a monolithic chain like Ethereum, state is global and accessible to all contracts. In a rollup-centric model, your application's state is isolated within the rollup's execution environment. You must design your data structures and access patterns around this sovereign state model, considering how data will be proven to and settled on the parent chain via fraud proofs or validity proofs.

Your application's architecture is dictated by your chosen rollup stack. Using a framework like the OP Stack, Arbitrum Nitro, or a zk-rollup SDK (e.g., zkSync's ZK Stack, Polygon CDK) provides the underlying consensus, sequencing, and proof-generation layers. Your development focus becomes the execution layer: writing the business logic in a compatible virtual machine (EVM, WASM, Cairo VM). You must understand your stack's specific precompiles, opcode support, and gas metering, as these differ from Layer 1.

A critical design pattern is cross-chain messaging. Your rollup app will need to communicate with the parent chain and potentially other rollups. This involves using the native bridge for asset transfers and a message passing protocol (like Arbitrum's L1→L2 retryable tickets or the OP Stack's CrossDomainMessenger) for arbitrary data. Architect your contracts to handle the asynchronous, trust-minimized nature of these messages, including potential delays and failure states.

You must also plan for data availability. In optimistic rollups, transaction data is posted to Ethereum's calldata, making it expensive but highly available. zk-rollups may use data availability committees or validiums. Your app's transaction throughput and cost profile depend on this choice. Furthermore, consider sequencer decentralization; while you may start with a single sequencer, your architecture should allow for a transition to a decentralized sequencer set or shared sequencer network like Espresso or Astria.

Finally, integrate essential tooling from day one. This includes a block explorer (Blockscout, Etherscan for your chain), indexing (The Graph, Goldsky), and oracle services (Chainlink CCIP, Pyth, API3). Your development workflow will rely on a local devnet (foundry-anvil, hardhat) configured for your rollup's parameters and a testnet deployment to validate cross-chain interactions before mainnet launch.

core-architectural-patterns

DESIGN PATTERNS

How to Architect a Rollup-Centric Application

Building applications for rollups requires a fundamental shift in architectural thinking. This guide explores core patterns for designing scalable, efficient, and user-friendly dApps that leverage the unique properties of Layer 2.

A rollup-centric application architecture fundamentally rethinks where computation and data reside. Instead of a monolithic smart contract handling all logic on Ethereum Layer 1 (L1), the core application state and business logic are executed on the rollup's Layer 2 (L2). The L1 contract is minimized to a verification and data availability layer, primarily responsible for accepting batches of transactions and proofs. This separation allows for orders-of-magnitude higher throughput and lower fees for users, as only compressed data and verification costs are settled on the expensive L1. The key is to maximize the work done in the low-cost L2 environment.

The Hybrid Smart Contract Pattern

A dominant pattern is the hybrid smart contract, which splits logic between L1 and L2. For an Optimistic Rollup like Arbitrum or Optimism, your L2 contract holds the canonical application state and processes user transactions. A corresponding, minimal L1 "gateway" or "bridge" contract manages deposits, withdrawals, and potentially verifies fraud proofs. For a ZK-Rollup like zkSync Era or Starknet, the L1 contract verifies a cryptographic validity proof for each batch. Your architecture must define clear interfaces for cross-layer messaging, such as token bridging via standard bridges or arbitrary message passing using protocols like Arbitrum's ArbSys or Optimism's CrossDomainMessenger.

Data Availability and Cost Optimization

Architecting for cost efficiency requires careful data management. Rollups like Arbitrum Nitro and Optimism Bedrock use calldata compression to batch transaction data on L1. As a developer, you can optimize further by designing state updates that minimize on-chain footprint. Consider storing large datasets or files on decentralized storage solutions like IPFS or Arweave, storing only content identifiers (CIDs) on-chain. For application logic, prefer computation over storage on L2, and structure transactions to avoid excessive L1 calldata usage, which is the primary cost driver. Tools like the arb-gas-info precompile on Arbitrum help estimate costs during development.

Handling Withdrawals and Cross-Chain Messaging

User experience hinges on seamless asset movement. The withdrawal process from L2 to L1 involves a delay period (7 days for Optimistic Rollups, minutes for ZK-Rollups). Your architecture should abstract this for users. Implement a standard bridge interface for token withdrawals and integrate third-party liquidity bridges like Across or Hop Protocol for instant exits. For arbitrary messages, use the rollup's native messaging system to trigger actions on L1, such as minting an NFT on Ethereum mainnet after a purchase on L2. Always account for the trust assumptions and security models of the bridging solutions you integrate.

Frontend and Indexing Strategy

Your application's frontend must connect to both L1 and L2 RPC providers. Use libraries like wagmi and viem configured with multi-chain support. Since rollups have their own block explorers and indexing timelines, you cannot rely solely on mainnet subgraphs. Implement a dual-indexing strategy: use a rollup-specific indexer (e.g., The Graph on Arbitrum) for fast, recent data and fall back to querying the rollup's RPC for real-time state. Consider account abstraction via ERC-4337 bundlers on L2 to enable gas sponsorship and session keys, dramatically improving UX. The frontend should dynamically detect the user's network and switch contexts appropriately.

In practice, start by prototyping core logic in Solidity or Cairo (for Starknet) for the L2 environment, using local development nodes like Arbitrum Nitro's nitro-testnode or Hardhat's L2 plugins. Thoroughly test cross-chain messages and withdrawal flows using testnet bridges. The end goal is an architecture where users interact almost exclusively with the low-latency, low-cost L2, with the L1 serving as a secure settlement backbone only for finality and broad interoperability. This pattern is the foundation for scaling Web3 to mainstream adoption.

key-concepts

ARCHITECTURE PRIMER

Key Rollup-Specific Concepts

Building on a rollup requires understanding its unique data and execution environment. These concepts define how your application interacts with the underlying blockchain.

Sequencers & Proposers

The sequencer is the primary node that orders transactions and produces blocks. The proposer (or validator) submits compressed transaction data (calldata) and validity proofs to the L1. Understanding their roles is critical for latency, censorship resistance, and finality.

Centralized Sequencer: Most rollups use a single, trusted sequencer for speed.
Decentralized Sequencer Sets: Emerging models (e.g., Espresso, Astria) use permissionless networks.
Proposer-Builder Separation: Separates block building from L1 submission for efficiency.

EXPLORE

Data Availability (DA) Layers

Rollups must publish transaction data so anyone can reconstruct state. The Data Availability Layer is where this data is stored and guaranteed to be accessible.

Ethereum Calldata: The original, secure but expensive DA solution.
EigenDA & Celestia: Modular DA layers offering cheaper, scalable data publishing.
Blobs (EIP-4844): Ethereum's dedicated data storage for rollups, reducing costs by ~90%.

Choosing a DA layer impacts cost, security, and interoperability.

EXPLORE

Bridging & Messaging

Moving assets and data between L1 and L2 requires specialized bridges. Native bridges are the official, canonical bridges built by the rollup team. Third-party bridges offer alternative routes, often with faster withdrawals.

Deposit Flow: L1 -> L2 messaging is typically fast (1-3 L1 blocks).
Withdrawal Flow: L2 -> L1 involves a challenge period (Optimism: 7 days) or a proof verification delay (zkRollups: ~1 hour).
Arbitrary Messaging: Protocols like Hyperlane and LayerZero enable cross-rollup communication.

EXPLORE

State Management

A rollup's state is the current snapshot of all accounts and contracts. Applications must understand how state is accessed and proven.

State Roots: A Merkle root representing the entire state, posted to L1.
State Proofs: For zkRollups, a validity proof confirms state transitions are correct. For Optimistic Rollups, fraud proofs can challenge invalid state.
State Growth: Long-term state storage solutions (like state expiry or Verkle trees) are critical for scalability.

EXPLORE

Fee Mechanisms

Rollup transaction fees have distinct components. The total fee typically covers:

L2 Execution Fee: Cost of computation/storage on the rollup itself.
L1 Data Publishing Fee: The largest cost, paid to post data to the Data Availability layer.
Sequencer/Proposer Margin: A small profit for network operators.

Fees are often paid in the rollup's native gas token (e.g., ETH on Arbitrum) or the L1's native token. EIP-4844 blobs have significantly reduced the L1 data fee component.

~90%

Fee Reduction with Blobs

Precompiles & Custom Opcodes

Rollups can expose precompiled contracts or custom EVM opcodes to offer L2-specific functionality at reduced gas costs.

Arbitrum Stylus: Enables Rust/C++ smart contracts via a custom WASM precompile.
zkSync Era's LLVM Compiler: Supports Vyper and Solidity via custom system contracts.
Optimism Bedrock's L1Block Contract: Provides easy access to L1 block attributes (number, hash, timestamp).

Using these can optimize gas and enable features not possible on Ethereum L1.

EXPLORE

L2 ARCHITECTURE

Rollup Feature Comparison: Arbitrum, Optimism, zkSync

Key technical and economic differences between major EVM-compatible rollups for application design decisions.

Feature / Metric	Arbitrum One	Optimism (OP Mainnet)	zkSync Era
Underlying Technology	Optimistic Rollup	Optimistic Rollup	ZK Rollup (zkEVM)
Fraud Proof Challenge Period	7 days	7 days	N/A (Validity Proofs)
Time to Finality (L1)	~1 week (for full)	~1 week (for full)	~1 hour
Transaction Cost (Typical)	$0.10 - $0.50	$0.10 - $0.40	$0.01 - $0.20
Native Account Abstraction
Precompiles Support	Full EVM equivalence	EVM equivalent (with differences)	Custom VM (zkEVM), limited precompiles
Primary Programming Language	Solidity, Vyper	Solidity, Vyper	Solidity, Vyper, Zinc
Dominant Sequencer Model	Single, permissioned (Offchain Labs)	Single, permissioned (OP Labs)	Single, permissioned (Matter Labs)
Native Token for Gas	ETH	ETH	ETH
Data Availability Layer	Ethereum (calldata)	Ethereum (calldata)	Ethereum (calldata)

bridging-and-ux-considerations

MANAGING BRIDGING AND USER EXPERIENCE

How to Architect a Rollup-Centric Application

Designing applications for rollups requires a fundamental shift in architecture, prioritizing seamless cross-chain interactions and a unified user experience.

Architecting for a rollup-centric world means designing your application with the assumption that user assets and activities will be distributed across multiple chains. The core challenge is abstracting this complexity from the end-user. Instead of a monolithic smart contract deployment on a single L1, your architecture should treat each rollup—whether an Optimistic Rollup like Arbitrum or a ZK-Rollup like zkSync Era—as a semi-autonomous instance of your application. A common pattern is to deploy a canonical version of your core logic on a settlement layer (like Ethereum mainnet) and lighter, high-performance versions on various rollups, with a messaging layer synchronizing critical state.

User experience hinges on efficient and secure bridging. Native rollup bridges, like the Arbitrum Bridge or the Optimism Portal, are the most secure for moving assets from L1 to L2, but they can be slow for withdrawals (with challenge periods for Optimistic Rollups). For faster L2-to-L2 interactions, you must integrate third-party bridges or leverage native cross-rollup messaging if available. Your architecture should implement a unified frontend that detects the user's connected chain, displays aggregated balances from all deployed instances, and intelligently routes transactions—using a liquidity bridge for small, frequent transfers and the canonical bridge for large, security-critical withdrawals.

Smart contract architecture must account for asynchronous state. Since messages between rollups and L1 are not instantaneous, your contracts should not assume synchronous finality. Use a pattern where actions initiated on one chain emit an event, which is relayed by an off-chain oracle or relayer to the destination chain, triggering a follow-up action. For example, a user locking tokens in a vault on Arbitrum could receive a minted representation of that vault position on Optimism after the cross-chain message is verified. Libraries like Hyperlane or Axelar provide generalized messaging APIs to abstract this relay logic.

Data availability and indexing present another layer of complexity. Users expect to see their full history and state regardless of which rollup they used. Your backend must index events from all your contract deployments across every supported chain and aggregate them into a unified data layer. Services like The Graph (with multi-chain subgraphs) or custom indexers are essential. This aggregated index powers your frontend, allowing users to see their total yield farming rewards accrued across Arbitrum, Base, and Polygon zkEVM as a single number.

Finally, cost optimization is a direct feature of your architecture. Rollups have distinct gas economics; structuring contract calls to minimize L1 data publication costs is crucial. Batch user operations, leverage storage writes that benefit from L2 compression, and consider using account abstraction (ERC-4337) to sponsor gas fees for users moving between chains. The goal is an application that feels like a single, cohesive product, not a collection of fragmented chain-specific apps, by making the underlying rollup infrastructure invisible to the end-user.

gas-and-fee-optimization

GAS AND FEE OPTIMIZATION STRATEGIES

How to Architect a Rollup-Centric Application

Designing applications for rollups requires a fundamental shift in mindset from L1 development. This guide covers architectural patterns to minimize transaction costs and maximize performance on Layer 2 networks like Arbitrum, Optimism, and Base.

Rollup-centric design starts with data availability and execution cost separation. On Ethereum L1, storage (SSTORE) is the primary cost driver. On rollups, the cost model flips: computation (CALL, hashing) and calldata become the dominant expenses, as this data is posted to L1 for security. Your architecture must minimize on-chain data and complex computations. For example, storing a user's nonce in a mapping costs gas on every update; consider using incrementing counters or off-chain signatures for state management instead.

Implement batchable transaction patterns to amortize L1 data costs across multiple users. Instead of having each user submit individual transactions, design a system where a relayer or a smart contract aggregator collects signed messages off-chain. A single on-chain transaction can then process hundreds of actions, drastically reducing the per-user cost. Protocols like Uniswap use this for permit2 signatures, and NFT marketplaces use it for bulk listings. The core contract should expose a function like executeBatch(UserOp[] calldata ops) that iterates through an array of compressed operations.

Optimize calldata compression aggressively. Use tightly packed arguments, uint128 instead of uint256 where possible, and leverage Axiom-style Merkle proofs for state verification instead of storing full histories. For frequent, low-value data (e.g., game scores, oracle price ticks), consider using a Data Availability (DA) layer like Celestia or EigenDA, or an L3 solution with a custom DA, to post data more cheaply than Ethereum calldata. Store only the cryptographic commitment (a hash) on the rollup.

Structure your contracts to leverage L2-native primitives. Most rollups offer precompiles or special opcodes for cost savings. Arbitrum Nitro's ArbSys precompile allows for efficient L1-to-L2 messaging. Optimism Bedrock introduced the L2OutputOracle for trustless bridging. Use these instead of building custom, expensive alternatives. Furthermore, design with gas token abstraction in mind: while ETH is the native gas token, some rollups like Arbitrum also support direct payment with stablecoins via gas sponsorship mechanics.

Adopt a modular state management approach. Keep the core, frequently accessed state and logic in a minimal, optimized verification contract on the rollup. Move complex logic, historical data, and front-end interactions to an off-chain component (a server or a decentralized oracle network) that submits only essential proofs. This pattern, used by dYdX v4 and other app-chains, turns your application into a sovereign rollup or settlement layer app, giving you full control over data and execution costs while inheriting Ethereum's security for finality.

ARCHITECTURAL PATTERNS

Implementation Examples by Rollup

Native Account Abstraction

zkSync Era has native support for Account Abstraction (AA) via its custom IAccount interface. This allows developers to build smart contract wallets and custom transaction validation logic directly into the protocol.

Key Implementation Pattern:

Implement the IAccount interface for your custom account contract.
Define validation logic (e.g., multisig, social recovery, session keys).
Users interact with your dApp via UserOperations that your account contract validates and executes.

Code Snippet - Skeleton Contract:

solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import {IAccount} from "@matterlabs/zksync-contracts/l2/system-contracts/interfaces/IAccount.sol";

contract MyCustomAccount is IAccount {
    function validateTransaction(
        Transaction calldata _transaction
    ) external payable returns (bytes4 magic) {
        // Custom signature validation logic
        require(isValidSignature(_transaction.signature), "Invalid sig");
        return ACCOUNT_VALIDATION_SUCCESS_MAGIC;
    }
    // ... executeTransaction logic
}

This pattern is ideal for onboarding Web2 users with sponsored transactions and flexible security models.

ROLLUP-CENTRIC APPS

Common Architectural Mistakes to Avoid

Building on a rollup introduces unique architectural considerations distinct from L1 development. Avoiding these common pitfalls is critical for performance, cost, and user experience.

High latency in rollup apps often stems from misunderstanding the sequencing and finality pipeline. While a transaction may be accepted by the sequencer in seconds, it must still be proven and settled on the L1, which can take minutes (e.g., 10-20 minutes for Optimism/Arbitrum).

Common causes:

UI assumes instant finality: Your frontend should differentiate between sequencer acceptance (fast) and L1 finality (slow).
Blocking on L1 confirmation: Avoid making critical state changes dependent on L1 finality. Use the sequencer's fast confirmation for UX, with fallback logic for reorgs.
Ignoring proving time: Zero-knowledge rollups (zkRollups) have additional latency for proof generation before the batch is submitted.

Fix: Implement a multi-stage confirmation status (e.g., 'Pending', 'Sequenced', 'Finalized') in your UI and smart contract logic.

resource-links

GUIDES

Development Resources and Tools

Resources and architectural concepts for building applications that treat rollups as the primary execution environment. These cards focus on concrete design decisions, tooling, and protocol tradeoffs developers face when shipping rollup-native systems.

Choosing the Right Rollup Stack

Rollup-centric applications start by selecting an execution and governance model that matches your security and UX requirements. Key factors differ significantly between Optimistic Rollups and ZK Rollups.

Key considerations:

Fraud proofs vs validity proofs: Optimism and Arbitrum rely on challenge periods, while zkSync and Scroll finalize state immediately with ZK proofs.
Finality and withdrawal latency: Optimistic rollups typically enforce ~7 day withdrawal windows to Ethereum L1.
EVM equivalence: Arbitrum Nitro and Optimism Bedrock support near-full EVM compatibility, reducing opcode and tooling gaps.
Governance and upgrades: Many rollups retain upgrade keys or security councils. This affects trust assumptions for app developers.

Actionable step: deploy a minimal contract on two candidate rollups and benchmark gas costs, RPC latency, and tooling friction before committing.

EXPLORE

Sequencer Architecture and Decentralization

Most production rollups still operate with a single centralized sequencer, which impacts censorship resistance and liveness. Application architects must design around this reality.

Design strategies:

Soft finality assumptions: treat sequencer confirmations as probabilistic until L1 inclusion.
Fallback RPCs: support multiple public and private RPC providers to reduce downtime risk.
User escape hatches: ensure users can force-include transactions via L1 if censorship occurs.
Future-proofing: track decentralization roadmaps like Optimism's fault proof system and Arbitrum's Sequencer Committee.

Actionable step: simulate sequencer downtime in staging and verify your app handles reorgs, delayed confirmations, and RPC failures without user fund loss.

EXPLORE

Data Availability and Blob Economics

Rollups depend on external data availability (DA) to publish transaction data. Ethereum blobs introduced in EIP-4844 significantly changed rollup cost structures, but alternative DA layers are increasingly relevant.

Core DA options:

Ethereum blobs: highest security, variable pricing, limited blob space per block.
Celestia: modular DA with lower costs and higher throughput, commonly paired with sovereign rollups.
EigenDA: restaked DA model with different trust assumptions.

Tradeoffs to evaluate:

Cost per byte under peak load
Light client verification complexity
Long-term data retrievability guarantees

Actionable step: model your app’s calldata growth over 12 months and stress-test blob pricing assumptions against historical Ethereum congestion.

EXPLORE

Cross-Domain Messaging and Composability

Rollup-centric applications rarely live on a single chain. Secure cross-domain messaging is required for asset movement, governance, and state synchronization.

Common patterns:

Canonical bridges: native bridges provided by the rollup, highest security but limited flexibility.
Interoperability protocols: Hyperlane, LayerZero, and Wormhole offer generalized messaging with different trust models.
Async UX design: users must understand message delays, retries, and failure modes.

Security practices:

Validate message origins and domains explicitly
Avoid assuming synchronous execution across chains
Monitor relayer health and message queues

Actionable step: design cross-chain flows assuming messages can be delayed or reordered, and make all state transitions idempotent.

EXPLORE

Developer Tooling for Rollup-Native Apps

Efficient rollup development relies on tooling that understands L2 quirks like gas pricing, precompiles, and cross-chain debugging.

Essential tools:

Foundry: fast Solidity testing with fork support for Optimism, Arbitrum, and zkSync.
Hardhat L2 plugins: network helpers for rollup-specific RPC and gas settings.
Block explorers: rollup explorers expose calldata, L1 batch references, and fault proof status.
Monitoring: track L1 inclusion delays, sequencer uptime, and bridge contract events.

Actionable step: add CI tests that fork both L1 and your target rollup to catch cross-domain edge cases before deployment.

EXPLORE

ROLLUP ARCHITECTURE

Frequently Asked Questions

Common technical questions and solutions for developers building on rollups like Arbitrum, Optimism, and Base.

The fundamental distinction lies in the fraud proof mechanism. Optimistic Rollups (ORUs) like Arbitrum and Optimism assume transactions are valid by default and only run computation to generate a fraud proof if a challenge is submitted during a 7-day dispute window. This makes them highly compatible with the EVM but introduces a long withdrawal delay to mainnet.

Zero-Knowledge Rollups (ZKRs) like zkSync Era and StarkNet use validity proofs. For every batch of transactions, they generate a cryptographic proof (a SNARK or STARK) that is verified on-chain instantly. This enables near-instant, trustless withdrawals but historically required building a new virtual machine, making EVM compatibility more complex (solved by zkEVMs). ZKRs also have higher proving costs but lower data publication costs to L1.

conclusion

ARCHITECTURE REVIEW

Conclusion and Next Steps

This guide has outlined the core principles for building applications that leverage rollup scalability. Here's a summary of key takeaways and resources for further development.

Architecting for a rollup-centric future requires a fundamental shift from monolithic, single-chain thinking. The core principles are: - Sovereignty through modularity: Decouple execution, settlement, and data availability. - Intent-centric design: Structure user interactions around desired outcomes, not low-level transactions. - Unified liquidity and state: Use interoperability protocols to create a seamless cross-chain user experience. Your application's architecture should treat the base layer as a security and coordination hub, not the primary execution environment.

To move from theory to implementation, start by instrumenting your existing application. Use tools like Dune Analytics or Flipside Crypto to analyze transaction patterns and identify bottlenecks. For new builds, frameworks like the OP Stack, Arbitrum Orbit, or zkStack provide pre-audited, customizable rollup clients. When integrating data availability, evaluate solutions like EigenDA, Celestia, or Avail based on your cost, throughput, and decentralization requirements. Always prototype with testnets like Sepolia or Holesky before mainnet deployment.

The ecosystem is evolving rapidly. Stay current by monitoring key developments: - Shared sequencers (like Espresso or Astria) for cross-rollup atomic composability. - Volition and sovereign rollup models for greater customization. - Proof aggregation networks to reduce verification costs. Engage with developer communities on the Ethereum R&D Discord, Optimism Forum, and zkSync Developer Hub. The goal is to build an application that is not just on a rollup, but is fundamentally architected for a multi-rollup ecosystem.