# Architecture

## Introduction

Zircuit is a EVM-compatible zero-knowledge (zk) rollup that delivers robust security guarantees through validity proofs built on proven rollup infrastructure. We combine the battle-tested OP Stack foundation with [OP-Succinct](https://succinctlabs.github.io/op-succinct/) built with a modified version of [Kona](https://github.com/op-rs/kona/tree/main/bin/client) to support [Sequencer-Level Security (SLS)](https://docs.zircuit.com/info/architecture/sls-deep-dive). SLS represents a distinctive capability that sets Zircuit apart from other networks. This feature proactively examines each transaction prior to block inclusion, detecting and preventing security threats and malicious behavior.

## Core Architecture

Zircuit's architecture is built around three fundamental components that work together to process transactions, generate proofs, and maintain secure interaction with Ethereum Layer 1:

### Sequencer

The sequencer layer is responsible for ordering and batching transactions to construct Layer 2 blocks. Built on the [OP Stack](https://docs.optimism.io/stack/getting-started) infrastructure, sequencers ensure reliable transaction processing and block production while maintaining compatibility with existing Ethereum tooling and development workflows.

### Provers

Zircuit integrates [Succinct's SP1](https://docs.succinct.xyz/docs/sp1/introduction) zkVM to generate zero-knowledge validity proofs for each block. These provers create cryptographic evidence that all transactions in a block have been executed correctly according to the protocol rules, enabling trustless verification without requiring full re-execution of the transactions.

### Smart Contracts

The Layer 1 smart contract infrastructure manages the core protocol functions, including state root updates, proof verification, and withdrawal processing. These contracts serve as the trust anchor between Zircuit's Layer 2 execution environment and Ethereum.

### Key Benefits

The hybrid architecture delivers several advantages over traditional rollup designs:

* **Fast Finality**: Validity proofs provide immediate cryptographic finality without waiting periods
* **No Challenge Period**: Withdrawals can be processed immediately upon proof verification
* **Battle-Tested Foundation**: Built on OP Stack's proven infrastructure for maximum reliability
* **Enhanced Security**: Zero-knowledge proofs provide mathematical guarantees of execution correctness

This documentation will guide you through the technical implementation details, integration patterns, and development workflows for building on Zircuit's rollup architecture.