The design goal of Linea is to establish a verifiable, scalable, and reproducible execution layer for Ethereum. It does not pursue single-point performance improvements, but instead attempts to expand simultaneously from the four dimensions of execution, proof, data availability, and state management, finding a long-term sustainable balance between security and compatibility for Layer2.
The core structure of Linea is zkEVM, which allows all EVM state transitions to be formally proved. Traditional ZK solutions often require sacrificing EVM compatibility for proof efficiency; Linea, however, chooses a fully compatible zkEVM, enabling all smart contracts to migrate with zero changes. The value of zkEVM lies not in execution speed, but in verification capability. When execution and proof are completely consistent, the Ethereum main chain can mathematically verify all Layer2 behaviors without relying on the honesty of sorters or external executors.
The underlying architecture of the proof system consists of three core modules: Execution Client, Prover, and Aggregator. The Execution Client is responsible for executing user transactions and generating EVM traces; the Prover converts each step of the execution trace into proof constraints; the Aggregator compresses multiple proofs into a single compressed proof for final submission to Ethereum. This layered structure allows Linea to maintain system efficiency even when proof costs are high, as each step can be executed in parallel.
The zkEVM circuit design of Linea adopts a pipelined structure, breaking down various operation codes into independent sub-circuits to allow proof generation to be split by task type. The advantage of this modular circuit is that when network load increases, proof generation can scale horizontally. The cost of proof generation does not increase linearly with the number of transactions but is determined by circuit complexity. This is a key engineering point for Linea's long-term scalability.
At the execution layer, Linea uses a Sequencer for transaction ordering. In the current phase, it is temporarily centralized for efficiency, but the roadmap clearly indicates that the orderer will gradually decentralize in the future, establishing a multi-node ordering network through staking mechanisms and task allocation logic. The decentralization of the ordering layer directly affects MEV distribution and censorship resistance, making this path crucial for long-term security.
In terms of data availability, Linea uses the Ethereum main chain as the DA layer, with compressed data and state roots written into Layer1. Compared to solutions using external DA layers, this design reduces cross-chain assumptions and lowers system complexity. The advantage of Ethereum DA lies in its security and maturity, allowing Linea not to build additional dependencies. This makes the entire trust model of Linea very clear: execution is on Layer2, verification and data are on Layer1, and finality is guaranteed by the main chain.
Linea adopts a compressed state model for state management. The complete state of Layer2 exists locally in Layer2, while Layer1 only stores the state root and proof. Any node can reconstruct a specific historical state through proof and state root, giving Linea replayability. This replayable structure makes system debugging and auditing quite clear and also makes protocol upgrades easier to manage. Verifiers do not need to carry the complete history but only need to verify whether the compressed proof is consistent.
The design of the verification path is a key engineering focus for Linea. After proof generation is completed, the Aggregated Proof will enter the verification contract, and the verification process will be executed by Ethereum. The time cost for Ethereum to verify zk proofs is much lower than re-executing all Layer2 transactions, allowing Layer2 to scale without sacrificing security. The high cost of the proof layer is reduced through aggregation, while the low cost of the verification layer is maintained through mathematical guarantees.
In terms of security, Linea's zkEVM circuits have undergone multiple layers of auditing. Prover, Verifier, Data Pipeline, and Sequencer Logic have all been inspected by third-party organizations. The team adopts a long-term formal verification approach, allowing the circuit model, state transitions, and constraint logic to be continuously corrected. Security is an engineering system, not a one-time audit, so Linea's architecture is designed with an updatable security mechanism rather than a one-off component.
In terms of composability, Linea's zkEVM fully replicates the Ethereum execution environment, making almost all mainnet toolchains and infrastructures directly compatible. For instance, Hardhat, Foundry, MetaMask, and Infura do not require additional adaptations. This makes the migration cost for developers extremely low, allowing ecosystem growth to outpace non-compatible ZK Rollups. Developers can directly reuse mature components from the mainnet, which is a structural advantage for Linea.
As the number of applications grows, Linea's zkEVM will take on more execution tasks, while the aggregation layer will take on more proof compression tasks. Since the circuits are modularized, expanding proof capabilities does not require modifications to the execution layer, allowing Linea to enhance performance through 'proof side expansion' rather than execution side expansion. This is a typical long-term scalable architecture.
In terms of ecosystem structure, Linea has formed a multi-layer application network consisting of DeFi, data services, identity systems, and contract platforms. These projects can share underlying verification security while enjoying lower execution costs and faster confirmation speeds. Since Linea's zkEVM is fully compatible, developers prefer to deploy complex contracts on Linea while considering Layer1 as the final settlement layer.
In the long term, Linea's direction is very clear: using Ethereum as the ultimate trust source, zkEVM as the execution engine, and a modular proof system as the source of performance. Scalability comes from proof pipelines, security comes from Ethereum DA, and application growth comes from compatibility. This design allows Linea to maintain a predictable evolutionary path over the next decade.
The true value of Linea lies in making scalability no longer opposed to security, allowing compatibility without sacrificing proof efficiency, and enabling execution and verification to be layered and composable. For large ecosystems requiring long-term stability, this is a more realistic engineering solution.
