What modular blockchains are, why data availability is critical, and how Celestia and EigenDA change the economics of rollups.

What is a modular blockchain

This article is part of our complete series on DeFi. If you're new to the topic, start with the pillar guide: DeFi for Beginners: What Decentralized Finance Is and How to Start.

A modular blockchain is an architecture where the three main functions of a blockchain —execution, consensus, and data availability— are separated into distinct layers. Each layer can be run by a specialized network that makes it very efficient, instead of forcing a single protocol to do everything.

It's the opposite of a monolithic blockchain like Solana or Bitcoin, where the same set of validators executes transactions, orders them, and stores the data.

Why this matters today: if Ethereum wants to scale to billions of users, it can't absorb all the costs on its L1. The rollup-centric strategy needs specialized layers that are cheap and robust. That's where Celestia, EigenDA, and other "data availability layers" (DA layers) come in.

The three layers of a modular blockchain

1. Execution layer: where smart contracts run and transactions are processed. Examples: Arbitrum, Optimism, Base, zkSync (all are rollups that execute).
2. Consensus layer: who decides block order and signs them. Usually Ethereum L1 or a specific chain.
3. Data availability (DA) layer: where raw transaction data is stored so anyone can verify it. This is the layer Celestia and EigenDA reinvent.

In a traditional rollup, transaction data is published to Ethereum L1 (in blobs, after EIP-4844). That's secure but relatively expensive. An external DA layer does the same more cheaply while keeping most guarantees.

Why data availability is the bottleneck

For a rollup to be trustworthy, anyone has to be able to reconstruct its state from data published somewhere verifiable. If that data disappears or is inaccessible, the rollup becomes a black box controlled by its operator.

That's why publishing data to a decentralized chain with availability guarantees is critical. The problem: space on Ethereum L1 (even in blobs) is limited and expensive. When Base, Arbitrum, and Optimism grow and push data to Ethereum, costs rise for everyone and a bottleneck forms.

The modular solution: use a chain specialized in DA that's cheaper and scales better for that specific use case. That's the role Celestia and EigenDA occupy.

Celestia: the first dedicated DA layer

Celestia is a Proof of Stake blockchain built from scratch as a data availability layer. It doesn't execute smart contracts (not Turing-complete); it only receives data, orders it, and publishes it.

Its key innovation is Data Availability Sampling (DAS): light nodes can verify with high probability that data is available without downloading the entire block. That allows Celestia to scale DA throughput while keeping the security of a light node accessible to anyone.

Celestia numbers:

• Sustained DA throughput: currently ~1.4 MB/s, with planned upgrades to 8 MB/s and beyond
• Cost per byte: an order of magnitude cheaper than Ethereum blobs
• Validators: ~150
• Token: TIA, used to secure the network

Who uses Celestia today:

• Manta Pacific (zkEVM rollup)
• Eclipse (rollup using SVM executing on Celestia)
• Movement Labs (rollup with Move VM)
• Hyperlane, Berachain (announcements and testnets)
• Multiple sovereign rollups and app-chains

The usual critique of Celestia: since it's not Ethereum, rollups that use Celestia as DA don't automatically inherit Ethereum's security. They're what's called sovereign rollups or alt-DA rollups, not "pure" rollups. In practice this implies a trade-off: lower cost in exchange for less inherited security.

EigenDA: EigenLayer's bet

EigenDA is the data availability solution built on EigenLayer, Ethereum's restaking protocol. The key difference with Celestia: instead of having its own token and validator set, EigenDA "rents" the economic security of already-staked ETH.

Ethereum validators can opt in to securing EigenDA by putting their staked ETH as collateral. If they fail their DA duty, they're slashed —they lose part of their ETH.

This brings several advantages:

• Inherited Ethereum security: economic collateral is ETH, not a new token.
• More alignment: rollups using Ethereum as settlement can use EigenDA as DA and maintain a single root of trust.
• Very high throughput: EigenDA reports capacity up to 15 MB/s, though real production numbers are usually lower.

Who uses EigenDA:

• Mantle (one of the first to migrate to EigenDA)
• AltLayer
• Cyber
• Layer N

EigenDA is newer than Celestia and is still proving its robustness in production. Its growth in 2025 was significant.

Celestia vs EigenDA: quick comparison

They aren't mutually exclusive rivals. In 2026 there are rollups that use both as redundancy, and there's technical debate about which scales better long-term.

Other relevant DA layers

• Avail (Polygon): dedicated DA chain, similar to Celestia in philosophy. AVAIL token.
• Near DA: data availability module on Near Protocol. Very cheap but less validated.
• EthStorage: focused on decentralized storage more than pure DA.

And always Ethereum L1 (blobs after EIP-4844) as the safest but more expensive option.

Implications for investors and developers

If you're an investor

DA layer tokens (TIA, AVAIL, EIGEN) are a bet on the modular thesis: the more rollups grow, the more DA demand, and the more revenue these chains generate. But there are several risks:

• Margin compression: if Ethereum L1 blobs keep getting cheaper, the price difference with external DA layers shrinks.
• Market centralization: probably 2-3 main DA layers will coexist, not 10. Betting on the right winner matters.
• Regulatory risk: EigenLayer's restaking model has legal complexity without clear precedent.

If you're a developer

If you're launching a rollup in 2026, the questions you need to answer:

1. Do you need maximum economic security (Ethereum blobs)?
2. Do you optimize for cost (Celestia, EigenDA, Avail)?
3. Do you want full Ethereum alignment (EigenDA)?
4. Do you prefer sovereignty and minimal dependencies (Celestia)?

There's no universal answer. Chains with high volume and low fault tolerance (perps DEX, derivatives) usually go to Ethereum blobs. Chains with many cheap transactions (games, social) use Celestia or EigenDA.

FAQ

Is modular always better than monolithic? No. Modular has scaling advantages but introduces complexity and inter-layer dependencies. Solana (monolithic) is simpler to operate and reason about. Each architecture has its sweet spot.

Why isn't Ethereum natively modular? It partly is. Ethereum L1 is evolving toward being the settlement + DA layer, while execution is delegated to L2. That's modularity. EIP-4844 with blobs was the first explicit step.

What happens if Celestia goes down? Rollups depending on Celestia for DA couldn't publish new transactions. Already-committed transactions remain valid. Risk similar to any critical dependency.

Does EigenDA inherit all of Ethereum's security? Not entirely. It inherits economic security (ETH staked as collateral) but not Ethereum L1 consensus security (data doesn't go in Ethereum blocks). It's an intermediate point.

What role do ZK rollups play here? ZK rollups also need DA. They can use Ethereum blobs, Celestia, EigenDA, or Avail just like optimistic ones. Choice depends on the same trade-offs.

Conclusion

Modular architecture stopped being theory years ago, and today is the foundation on which Ethereum's scaling and other L1s are built. Celestia and EigenDA represent two distinct but complementary visions of how to solve the data availability problem: one sovereign, the other ETH-aligned.

By 2026, knowing which DA layer each rollup you use (or invest in) employs is part of basic due diligence. Not all rollups are equal, and the DA choice influences their guarantees, costs, and roadmap.