Modular Blockchains Explained: Celestia, EigenDA & the Future of Scaling
Last updated: March 2026
Key Takeaways
- •Modular blockchains separate consensus, data availability, and execution into layers
- •Monolithic chains like Ethereum do everything; modularity enables specialization
- •Celestia (DA layer), Arbitrum (execution layer), and Ethereum (settlement) work together
- •Modular design enables extreme scalability but adds complexity and fragmentation
Monolithic vs Modular Blockchains
Monolithic Architecture
Monolithic blockchains like Ethereum, Bitcoin, and Solana do everything themselves:
- • Consensus: Validate transactions and reach agreement on block order
- • Data Availability: Store transaction data so nodes can verify the chain
- • Execution: Run smart contracts and state transitions
- • Settlement: Finalize transactions and resolve disputes
This simplicity is elegant but creates bottlenecks. Ethereum can process ~15 transactions per second because resources are split across all four functions.
Modular Architecture
Modular blockchains specialize: each layer does one job exceptionally well, then composes with others.
Data Availability Layer: Stores transaction data (Celestia, EigenDA)
Execution Layer: Runs transactions and state (Arbitrum, Optimism, StarkNet)
Settlement Layer: Finalizes and resolves disputes (Ethereum)
Consensus: Separate mechanism for settlement layer
By specializing, each layer can optimize independently. Celestia becomes world-class at data availability without worrying about execution. Arbitrum becomes world-class at computation without redundantly storing data.
Data Availability Layers
The data availability problem: For a blockchain to be trustlessly verified, its transaction data must be stored somewhere. In monolithic chains, all full nodes store all data, but this limits scalability.
Celestia: Specializing in Data Availability
Celestia is a blockchain optimized solely for data availability. It doesn't execute transactions—it just securely stores data. This allows Celestia to scale to massive throughput (40 MB/s of data).
Execution layers like Arbitrum post transaction batches to Celestia, then prove validity on Ethereum. This separates concerns: Celestia proves data was available, Arbitrum proves computation was correct.
EigenDA: Restaking-Based DA
EigenDA uses Ethereum validators to provide data availability through restaking. Operators can participate in DA without running new infrastructure, leveraging existing Ethereum security.
DA Sampling
A key innovation: light clients don't need to download entire blocks. They download small random samples to statistically verify data availability. This makes light clients much faster and cheaper.
Execution and Settlement Layers
Execution Layers
Execution rollups process transactions and maintain state. They post compressed batches to DA layers and proofs to settlement layers, but don't store all data themselves.
Optimistic vs ZK Execution
Optimistic Rollups (Arbitrum, Optimism): Assume transactions are valid; fraud provers can challenge incorrect state within a dispute window
ZK Rollups (StarkNet, zkSync): Prove computation is correct cryptographically; no dispute window needed
Settlement Layers
Settlement layers are typically existing monolithic chains (Ethereum). They don't execute transactions; they verify proofs from execution layers and finalize state. Ethereum acts as the ultimate source of truth and provides security guarantees.
Key Modular Blockchain Projects
Celestia (TIA)
Pure data availability blockchain. Enables low-cost sovereign rollups without Ethereum's base fees. Rollups like Dymension and Rollups-As-a-Service providers deploy atop Celestia.
Arbitrum (ARB)
Optimistic rollup on Ethereum. Executes transactions at scale while inheriting Ethereum security. Currently posts to Ethereum's calldata but can be configured to use DA layers.
Optimism (OP)
Similar to Arbitrum, Optimism is an optimistic rollup scaling Ethereum. Focus on user experience and developer tooling. Plans for modular scaling through Alt-DA support.
StarkNet (STRK)
ZK rollup with CAIRO runtime. Uses zero-knowledge proofs for state verification. More complex but avoids dispute windows. Supports Cairo programming language.
Avail (AVL)
Data availability and light client focused. Optimized for light clients to verify data with minimal bandwidth. Powers sovereign rollups and light clients.
Eigenlayer (EigenDA)
Restaking protocol providing DA through existing Ethereum validators. Leverages Ethereum security for data availability without new blockchain.
Modular Tradeoffs & Challenges
Advantages of Modularity
- ✓ Extreme Scalability: Each layer optimizes independently; data availability becomes non-bottleneck
- ✓ Flexibility: Execution layers can choose security model (optimistic vs ZK), language, etc.
- ✓ Reusability: Multiple execution layers share same DA and settlement infrastructure
- ✓ Sovereign Rollups: Execution layers can be updated without settlement layer coordination
Challenges & Concerns
- ✗ Complexity: Understanding modular stack requires expertise. User experience is complicated.
- ✗ Liquidity Fragmentation: Liquidity splits across multiple execution layers, reducing efficiency
- ✗ Cross-Layer Bridges: Moving value between layers requires bridges, adding risk and friction
- ✗ Economic Security: Shared security is weaker than independent chains; validators might be inadequately incentivized
- ✗ Unproven at Scale: Most modular stacks are nascent; long-term economic sustainability unclear
The Blockchain Trilemma Still Applies
Modularity doesn't solve the fundamental trilemma—blockchains can't optimize for decentralization, security, and scalability simultaneously. Modular designs shift the tradeoff but don't eliminate it. A DA layer that's extremely scalable might require running a full node with significant resources, reducing decentralization.
Frequently Asked Questions
Is Ethereum monolithic or modular?
Currently, Ethereum is monolithic—it does everything. However, Ethereum is evolving toward supporting modular stacks. Danksharding will optimize Ethereum's data availability layer. In the future, Ethereum will settle and finalize execution-layer transactions while specializing in security and consensus.
Can rollups on different DA layers communicate?
Yes, but it requires cross-layer bridges. A rollup on Celestia can't directly call one on EigenDA—they need a bridge smart contract that atomically swaps or transfers value. This adds friction but is technically possible.
Which is better: modular or monolithic?
Neither is categorically better. Monolithic chains are simpler and have network effects. Modular stacks scale infinitely but are complex and fragmented. The market will likely support both, with monolithic chains serving as settlement layers and rollups as execution.
What's the investment thesis for modular blockchains?
If modular stacks become dominant, their tokens capture value from becoming internet-scale infrastructure. Celestia captures DA value, Arbitrum captures execution value, and Ethereum captures settlement value. Early bets on modular infra could be high-ROI if adoption scales.
Is Solana modular?
Solana is monolithic. It does all four functions. However, Solana is exploring modular designs through Firedancer (a new validator client) and state compression techniques that might enable execution/DA separation in the future.