OP Stack

The OP Stack is an open-source, modular software stack designed for building highly scalable and interoperable Layer 2 (L2) blockchains, with the Optimism Mainnet serving as its first and flagship implementation. It provides the core components—such as a rollup client, data availability layer, and bridging protocol—necessary to construct an Optimistic Rollup that derives its security from a parent Layer 1 (L1) chain like Ethereum. By standardizing these components, the OP Stack enables developers to launch their own custom blockchains, known as OP Chains, which can share security, a communication layer, and a technology roadmap.

At its architectural core, the OP Stack employs a modular design philosophy, separating key functions like execution, settlement, consensus, and data availability into distinct modules. This allows developers to swap components, such as choosing a different data availability solution or consensus mechanism, to tailor the blockchain for specific use cases. The stack's modularity is foundational to the Superchain vision, a proposed network of interconnected OP Chains that can communicate seamlessly and share infrastructure, creating a unified ecosystem rather than a collection of isolated scaling solutions.

Key technical components of the OP Stack include the op-node, which is the rollup client responsible for deriving the L2 chain from L1 data; the op-geth, a modified version of the Go-Ethereum client that handles execution; and the op-batcher, which compresses transaction data and posts it to Ethereum. The stack also defines a standard bridging mechanism for secure message passing between chains. This standardized toolkit reduces development overhead and fosters interoperability, as chains built with the same stack can understand each other's states and transactions natively.

The development and governance of the OP Stack is managed by the Optimism Collective, with upgrades proposed and ratified through its decentralized governance process. This ensures the stack evolves in a transparent, community-driven manner. Major milestones in its evolution include the Bedrock upgrade, which significantly reduced fees and improved modularity, and the ongoing development of fault-proof systems to transition from the current fraud-proof model to a more robust security architecture for dispute resolution.

In practice, the OP Stack is used not only by the Optimism network but also by other major projects like Base (built by Coinbase), Zora Network, and Mode Network. These OP Chains demonstrate the stack's flexibility, supporting diverse applications from decentralized social media to NFT marketplaces. By providing a shared, high-quality codebase, the OP Stack aims to accelerate the development of the rollup-centric future envisioned by Ethereum, where scalability is achieved through a vibrant ecosystem of interoperable L2s.

The OP Stack is a collection of modular, open-source components designed for constructing highly scalable Layer 2 blockchains known as Optimistic Rollups. At its core, it separates the blockchain into distinct functional layers: the Execution Layer (which runs the Ethereum Virtual Machine), the Derivation Layer (which sequences and batches transactions), the Settlement Layer (which handles dispute resolution and finality on Ethereum), and the Governance Layer (which manages upgrades). This modularity allows developers to swap out components, like a consensus mechanism or data availability solution, to create a blockchain tailored to specific needs without building from scratch.

The stack operates on a fault-proof system (previously called fraud proofs) to ensure security. Transactions are processed cheaply and quickly on the Layer 2 chain, with only compressed transaction data and state roots periodically posted to Ethereum Layer 1. This data commitment acts as a cryptographic promise that can be challenged during a dispute window, typically seven days. If a challenge is successful, the faulty state update is reverted, securing user funds. This architecture enables the high throughput and low fees characteristic of Optimism's Superchain vision, where multiple chains share security, communication layers, and a unified upgrade process.

A key innovation of the OP Stack is its Bedrock upgrade, which refactored the architecture for greater efficiency and modularity. Bedrock reduced data posting costs to Ethereum by introducing an optimized batch compression format and minimized latency for depositing funds from L1 to L2. Furthermore, the stack's design philosophy embraces a modular, multi-client future. Just as Ethereum has multiple execution clients (e.g., Geth, Nethermind), the OP Stack is being developed to support multiple, interchangeable op-node clients, reducing centralization risk and increasing network resilience.

The end goal of the OP Stack is to facilitate the Superchain, a network of interoperable Layer 2 chains that share a common technological foundation and communication protocol. Chains built with the OP Stack, such as Base, Zora, and Mode, can seamlessly communicate and compose with each other via native cross-chain messaging, creating a unified ecosystem rather than isolated scaling silos. This interoperability is managed through a collective governance model and shared standards, making the OP Stack not just a development toolkit but a framework for a scalable, collaborative blockchain future.

The OP Stack is a modular, open-source software stack developed by Optimism for building highly scalable and interoperable Layer 2 blockchains. At its core, it provides the foundational components for a blockchain, including execution, consensus, and settlement layers. Its primary goal is to foster standardization, allowing different chains built with it—collectively called the Superchain—to share security, a communication layer, and a unified development stack. This approach contrasts with isolated, single-chain scaling solutions.

Architecturally, the stack is designed with modularity and upgradability as first principles. Key modules include the Rollup Client (derived from Go-Ethereum), a Batch Submitter for data compression, and a Fault Proof system for verifying state transitions. By standardizing these components, the OP Stack enables developers to launch their own custom Layer 2 or Layer 3 chains (often called OP Chains) without building the entire infrastructure from scratch. This reduces complexity and accelerates deployment.

The long-term vision, the Superchain, is a network of these independent but seamlessly connected OP Chains. They will share a bridging protocol and a cross-chain messaging layer, enabling assets and data to move between chains as easily as within a single network. This interoperability aims to solve the liquidity fragmentation common in multi-chain ecosystems, creating a cohesive user experience akin to navigating different applications on a single computer operating system.

Governance of the OP Stack and the evolving Superchain standards is managed through a collective model. The Optimism Collective, a decentralized governance structure, oversees protocol upgrades and resource allocation via its Token House and Citizens' House. This ensures the stack's development remains aligned with public benefit and decentralization, rather than being controlled by a single entity. The stack's code is MIT-licensed, encouraging broad adoption and forkability.

In practice, the OP Stack has been adopted for major networks like Optimism Mainnet, Base, and Zora Network. Its design allows for sovereign chains that can implement their own governance and fee models while inheriting shared security from Ethereum. Future development, under the Bedrock architecture and beyond, focuses on further modularization, introducing alternative data availability layers, and refining the fault proof mechanism to transition from optimistic rollups to zk-powered validity proofs.