Build modular

This section will explain the advantages of building on modular blockchains like Celestia.

Scalability challenges

Blockchain architectures as they exist today are inherently not scalable.

To scale, blockchains must increase the number of transactions they can process while still remaining performant and decentralized (enabling average users to verify the chain).

High and unstable gas costs are also prohibitive for a large number of use cases, preventing many users around the world from participating in web3 or interacting with dapps.

For blockchains and web3 to reach mass adoption, challenges around both scalability and accessibility have to be solved.

Evolution of blockchains

Blockchains have evolved over time from application-specific networks like Bitcoin to shared smart contract platforms like Ethereum, which allow developers to deploy their own applications with business logic and state, without having to bootstrap their own blockchain from scratch.

Modular blockchains

What we're seeing happen now is another paradigm shift. We're moving away from monolithic designs to modular designs, where execution is separated from data availability and consensus (like Eth2 and Celestia).

Most blockchain architectures today are monolithic - they are responsible for all four core functions of a blockchain:

• Execution - executing transactions that update the state correctly. Thus, execution must ensure that only valid transactions are executed, i.e., transactions that result in valid state machine transitions.
• Settlement - an environment for execution layers to verify proofs, resolve fraud disputes, and bridge between other execution layers.
• Consensus - agreeing on the order of the transactions.
• Data Availability (DA) - making the transaction data available. Note that execution, settlement, and consensus require DA.

Modular blockchains decouple these functions among multiple specialized layers, and only specialize in only a few functions, rather than all of them.

Scalability

Modular blockchains achieve scalability in a few different ways.

Block size

At Celestia’s center is a core mathematical primitive: data availability sampling.

Data Availability Sampling enables Celestia Light Nodes to provide almost the same security guarantees as a full node. As the light node count increases, the block size can be increased linearly to its growth.

Now the only limit for block size (throughput) is the number of light nodes in the network.

This primitive allows Celestia to be the first blockchain that can scale its block size with the number of users.

Specialization

Because of the decoupling of functionality, each layer can specialize in one or many of the core functions of a blockchain.

This allows each layer to focus on becoming the most optimal at its use case without the limitations of the requirement of interoperability with other layers.

When the components become modular, those using or building the system don’t have to know or care about everything. They only have to care about a subset of the features. Specialization is the way to ensure maximum focus, performance, and capacity.

Resource pricing

By decoupling consensus from execution, Celestia can have much more efficient resource pricing than monolithic chains. Transactions published to the network can be charged purely based on the size of the data being submitted.

State growth and historical data are treated separately in Celestia. Celestia only stores historical data from rollups (measured and paid in bytes), while rollups handle and meter their own state execution.

This enables completely separate fee markets for execution and data availability, allowing fundamentally orthogonal resources to be priced by the market independently, resulting in more accurate and flexible pricing.

This means that spikes of higher throughput in one environment cannot affect another, separate layer.

Shared execution and monolithic blockchains

Most blockchains share execution with countless other applications and users of those applications.

If you compare this to how scalability is achieved in the traditional tech stack, where applications have their own servers or run their own "serverless" infrastructure that spins up a dedicated execution environment / container specifically for that individual application, the bottleneck becomes pretty clear.

Scalability can typically be achieved in two ways - horizontal and vertical scaling.

Applications on traditional tech infrastructure can handle tens of millions of interactions per second by scaling both horizontally as well as vertically, while blockchains have struggled to reach thousands of transactions per second while still remaining decentralized.

In addition to scaling the protocol itself (vertical), Celestia enables horizontal scalability. Developers can launch their own application-specific chains as rollups, similar to how Cosmos Zones enable developers to deploy their own application-specific blockchains.

Modular blockchains are a paradigm shift in blockchain design that aim to solve the challenges around both scalability as well as accessibility, opening the door to a larger number of use cases, and ultimately enabling web3 to reach mass adoption.

Building on Celestia

There are a handful of ways developers can build on Celestia.

Smart contracts

The easiest way to get started will be to deploy a smart contract to a rollup chain already running on Celestia.

The barrier to entry is low in that you can use your existing skillset without having to learn anything new.

You can write any language and use any execution environment you’d like, including Solidity or Vyper and the EVM or Cosmos and Go.

You can use Rollkit to deploy a rollup for your favorite execution environment connected to Celestia.

Sovereign rollups

One of the most powerful value propositions of Celestia is the idea of Sovereign Chains.

Rollups on Ethereum are effectively "enshrined" to Ethereum because Ethereum is responsible for validating their transactions. This makes them tightly linked.

Celestia enables a new type of rollup: sovereign rollup chains. These are independent chains that are similar to an independent L1.

Execution layers

Unlike Ethereum, Celestia has no enshrined settlement layer built in. Instead, there will be various settlement layers available to enable developers to easily deploy their own rollup or application-specific chain to Celestia.

Celestiums (Ethereum)

Celestiums allow developers to deploy to a rollup using Celestia as DA and Ethereum as settlement.

Ethereum rollups batch data from multiple transactions into a single transaction. This rollup transaction data (calldata) is posted to Ethereum but not executed directly.

A Celestium is an L2 chain that uses Ethereum for settlement plus dispute resolution, and Celestia for data availability.

This provides high throughput data availability for Ethereum L2s with a higher level of security than other off-chain data availability techniques.