Modular vs Monolithic blockchains: introduction to Celestia, the first modular blockchain.

Published in
5 min readMay 4, 2022


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Modular and Monolithic blockchains are two terms that are now frequently used, it is essential to clearly understand how different they are. This article is inspired by Mustafa Al-Bassam’s speech at the Modular summit. Mustafa is the co-founder of Celestia and CEO of Celestia Labs.

Here, we answer main questions and introduce Celestia, the first modular blockchain. 👇

What is a Monolithic Blockchain?

👉A monolithic blockchain is a blockchain that handles 4 components:

  • Consensus
  • Data availability
  • Execution
  • Settlement

on its own. All major L1s are monolithic blockchains because they handle those components, such as Bitcoin or Ethereum.

What does Consensus mean?

👉Consensus is responsible to take arbitrary messages (transactions) and order them

What does Data availability mean?

👉Data availability is responsible to publish the ordered messages. This is important because otherwise users and App would not know what the current state of the chain is.

What does Execution mean?

👉Execution takes messages that have been agreed on, ordered and made available by consensus and data availability. Then it does computation and processing on those messages to output a “state” (ex: your current balance)

What does settlement mean?

👉Settlement is a special case of execution layer. It’s an execution layer that bridges all the execution layers together.

What is a Modular Blockchain?

👉 A Modular blockchain is a blockchain that fully outsources at least one of the 4 components (Consensus, Data Availability, Execution, Settlement) to an external chain.

What is NOT a Modular Blockchain?

👉 It’s not a blockchain that handles all components but has a modular software design. This does not make it a modular blockchain

👉 It’s not a network of blockchains were each blockchain handles all components, such as Avalanche’s subnets

What are the different Ethereum-centric configuration chains?

👉There are 3 different configurations which are:

  • Monolith
  • Rollup
  • Validium

What is a rollup?

👉A rollup is a Layer 2 solution to scale a monolithic blockchain like Ethereum. It handles transaction executions off-chain and the remaining tasks (data availability, consensus, settlement) on-chain. Rollups bundle many transactions into one on the L1

What is a Validium configuration?

👉The validium configuration is similar to a rollup except that the data is NOT stored on the main L1 chain, it is done off-chain. This is we called that a “Side chain” Check @evan_van_ness‘s tweet:

Now, let’s see how Celestia differs from that. There are three Celestia-centric configurations

  1. The sovereign rollup
  2. The settlement rollup
  3. The Celestium configuration

What is a Sovereign Rollup?

👉A Sovereign Rollup uses Celestia for data availability & consensus only. The benefit here is that if you hard-fork a monolithic blockchain, you have to fork the consensus layer, meaning that you lost the security of the original chain.

This is not true for modular blockchains. You just fork settlement & execution layers and still benefit from the security of the consensus layer. Imagine how easy it will be to create its own chain on top of Celestia and benefit from its underlying security & decentralization.

What is a Settlement Rollup?

👉Settlement Rollup is like a standard rollup except that it’s only optimized for settling other rollups on top of it.

With Cevmos, rollups can then be deployed on top of the Evmos settlement rollup. Therefore, anyone can deploy an Evmos-based chain (Cosmos SDK + EVM built-in chain) implemented as a Celestia rollup Check the article here:

What is a Celiustium?

👉Celestium is a Validium that uses Celestia for Data Availability. This is slightly different from a Validium because the committee can be slashed if they misbehave thanks to Celestia’s network light node

What are the benefits of a modular blockchain?

👉Scalability: modular blockchains are more scalable because there is a separation of resources, meaning that each node is more specialized to a specific function, resulting to more efficiency.

👉Flexibility: because devs are free to experiment any execution environment on a modular blockchain

👉Sovereignty via sovereign rollups: With sovereign rollups, you can have your own L1 execution environment that has its own social consensus


Over the past 10 years, we’ve been stuck in this kind of circle of L1 chains being created all the time because the previous L1 could not scale and had issues.

Celestia changes everything and innovate with its modular aspect. It’s now time to build modular frens.


Imperator is a professional proof-of-stake validator, we provide a reliable infrastructure and support more than 20 blockchains with +30,000 delegators, with a focus on the Cosmos ecosystem.

If you want further information about, here are the useful links:





See you very soon Cosmonaut! ⚛️

The Imperator team.




Researcher @ Chorus One. Interested in every aspect of finance and cryptocurrencies. Twitter: