> For the complete documentation index, see [llms.txt](https://wiki.solaxy.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wiki.solaxy.io/core-concepts/rollup-architecture.md).

# Rollup Architecture

Solaxy is a modular Layer 2 rollup that runs off-chain execution while anchoring security and finality to Solana Layer 1. Its architecture is designed for performance, flexibility, and compatibility with Solana-native tooling.

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#### 🧱 Core Components

**1. Sequencer**

The sequencer is responsible for ordering and bundling transactions. Solaxy uses a **deterministic sequencer** that ensures consistent execution and minimizes latency. 

**2. Execution Layer**

Solaxy runs **Solana smart contracts** inside a **zkVM**, specifically the **SP1 zero-knowledge virtual machine by Succinct**. This allows existing SVM-based programs to execute inside a scalable rollup without code changes.

**3. State Transition Function**

This is the core logic that determines how transactions modify the system’s state. Solaxy has implemented a robust state transition function that mirrors Solana’s execution semantics, ensuring compatibility and reliability.

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#### 🔁 Off-Chain Execution & On-Chain Settlement

Solaxy processes transactions off-chain to achieve higher throughput and lower costs. Once a batch of transactions is processed, the rollup:

1. Generates a **proof of correctness**
2. Publishes **transaction data + proof** to Solana L1
3. Commits the new **state root** on-chain

This preserves security while offloading computation from Solana L1.

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#### 📦 Data Availability

Solaxy supports modular data availability layers:

* **Primary:** Solana L1 (for production-grade security)
* **Optional:** Celestia (for bandwidth-optimized configurations)

DA ensures that anyone can independently verify the current rollup state.

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#### 🌉 Bridging Layer

Solaxy integrates with **Hyperlane** to power permissionless, modular cross-chain messaging. The bridge connects:

* **Solana ↔ Solaxy**
* **Ethereum ↔ Solaxy** 
* **Solana ↔ Ethereum** 

The bridging layer supports native asset transfers and message passing between ecosystems.

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⚙️ Modular Design via Sovereign SDK

Solaxy is built using the [**Sovereign SDK**](https://github.com/Sovereign-Labs/sovereign-sdk), which enables:

* Plug-and-play data availability layers
* Configurable sequencing & settlement logic
* zkVM integration

This makes Solaxy highly composable and adaptable for the future of rollup infrastructure on Solana.