Crypto glossary
Modular blockchain
A modular blockchain splits core jobs such as execution, settlement, consensus and data availability into separate layers instead of one chain.
A traditional, or monolithic, blockchain handles everything in one place: it runs transactions, orders them, agrees on the result and stores the data. A modular design hands these jobs to specialized layers. One network might only order and publish data, while rollups on top execute transactions and a third chain settles disputes and proofs.
Ethereum's rollup-centric roadmap is the best-known modular approach: L2s execute transactions and Ethereum provides settlement and data availability. Celestia was built as a dedicated data and consensus layer that other chains can plug into. Monolithic chains such as Solana take the opposite route, scaling a single fast network.
Modularity lets each layer be optimized and lets projects launch their own chains cheaply, but it fragments liquidity and users across many networks and adds bridges and trust assumptions between layers. Whether modular or monolithic scaling wins is still an open debate.
Example
A game launches its own rollup that executes moves, publishes transaction data to a separate data availability layer and settles withdrawals on Ethereum, three layers working as one product.
