Modular blockchains are changing the way we design blockchain products.

Blockchain design has traditionally followed a monolithic model. In a monolithic blockchain, like early versions of Ethereum and Bitcoin, the core functions of a network—execution, consensus, data availability, and settlement—are tightly bundled into a single layer. This architecture made sense in the early days of crypto. It ensured security and simplicity. But as blockchains started scaling and diversifying, the limitations of the monolithic approach became clear.

The problem with monolithic blockchains is that they struggle to scale efficiently. When execution, consensus, and data availability all happen in the same place, every node has to do everything. That leads to congestion, higher fees, and a tradeoff between decentralization and performance. As Ethereum expanded, the demand for apps outpaced what the base layer could handle. Bitcoin, by design, remains limited in throughput to prioritize immutability and simplicity.

Modular blockchains offer a different approach. Instead of putting everything into one layer, modular systems split responsibilities across separate components. Execution happens in one layer. Consensus in another. Data availability can be handled elsewhere. This separation makes it easier to optimize each piece for its job. Projects can choose how decentralized or fast they want each part to be, depending on their use case.

Hemi is built with this modular architecture in mind. It connects the worlds of Bitcoin and Ethereum by enabling decentralized applications to operate with cross-chain awareness. Instead of forcing everything to run through Ethereum’s monolithic structure, or being limited by Bitcoin’s narrow scripting rules, Hemi creates a system where developers can selectively interact with each chain’s strengths. Smart contracts on Hemi can access Bitcoin data directly without needing trusted intermediaries, and they can settle on Ethereum using familiar tools like Solidity.

This kind of modular approach doesn’t just improve scalability—it opens up new design spaces. Developers can use Hemi to create apps that are secure like Bitcoin, programmable like Ethereum, and scalable across multiple chains. The separation of layers also makes upgrades more flexible. Individual modules can improve without needing a full fork or rebuild.

In summary, modular blockchains shift away from the single-stack design of monolithic blockchains like Bitcoin and Ethereum. By breaking up the core responsibilities of a blockchain, they offer more flexibility, better performance, and new ways to build secure and scalable applications. Hemi represents this shift, giving developers tools to build across chains in a way that was never possible with traditional designs.