Definition
The execution layer is the part of a blockchain protocol responsible for interpreting transactions, applying state transitions, and maintaining the canonical state database according to the network’s execution rules. It defines the transaction format, state model, and computation environment, including smart contract semantics and virtual machine behavior, while interfacing with the consensus layer that orders blocks and finalizes the resulting state updates.
In Simple Terms
The execution layer is the component of a blockchain where transactions are processed and the shared state is updated. It runs the logic of smart contracts and records the resulting data on-chain, while another component of the system focuses on agreeing which blocks and state updates are accepted.
Context and Usage
The term execution layer is commonly used in discussions of modular blockchain architecture, protocol design, and client implementations. In environments such as Ethereum, it refers to the subsystem that hosts the EVM, validates transaction correctness, and manages account and contract state. It is typically contrasted with the consensus layer, which provides block ordering, validation rules for block structure, and finality guarantees for on-chain state.