Modular Blockchain
A modular blockchain is one that separates the core functions of a blockchain — execution, settlement, consensus, and data availability — into distinct, swappable layers. This is the opposite of a monolithic blockchain (like Solana) where all functions are handled by a single chain.
✦ Key Insight
Modularity is the architectural bet behind most of the Ethereum scaling roadmap. For traders, it determines which chains will likely have cheap, fast trading in the future and where risk sits in each part of the stack.
✕ Common Misconceptions
Confusing "modular" with "more secure" — modular designs make different trust trade-offs, not strictly better ones.
Treating all rollups as equivalent regardless of their settlement and DA choices.
Ignoring withdrawal times when comparing modular L2s.
Detailed Explanation
How It Works: An execution layer (a rollup) handles transactions and produces a compact proof or state root. A data availability layer (Ethereum blobs, Celestia, EigenDA) publishes the underlying data. A settlement layer verifies proofs and resolves disputes. Each layer can be upgraded independently.
FAQs:
Is modular always better than monolithic? No — there are real trade-offs in composability and latency.
Who picks the data availability layer? The rollup team, usually as a permanent architectural choice.
In Practice
Dig Deeper
Shared Sequencer
A shared sequencer is a decentralized network of nodes that orders transactions on behalf of multiple Layer 2 rollups simultaneously. Rather than each rollup running its own centralized sequencer, they share an external ordering layer to enable cross-rollup composability and resist censorship.
Rollup
A rollup is a Layer 2 scaling method that bundles many transactions together before posting them to a Layer 1.