A closer look at OP Stack and Optimism's Superchain

What is Optimism Stack?

The OP stack powers the different chains that make up the Superchain ecosystem. Developed and maintained by the Optimism Collective, it benefits the Ethereum community by providing a framework for launching new L2 blockchains.

Optimism Bedrock is the current version of the OP Stack. Released June 6, 2023, the Bedrock release reduces gas fees through batch compression, shortens Ethereum to Optimism deposit times, increases bridge security, enables fault proofs and validity proofs, improves node performance, and further equalizes Optimism and Ethereum.

OP Stack is not limited to optimistic rollups but extends to various blockchain architectures. This flexibility is evident in its support for the Superchain concept, which aims to merge OP Mainnet and other chains using the OP stack into a single unified network of OP Chains sharing components like bridging, communication layers, and security.

Although the OP Stack significantly simplifies the process of creating L2 blockchains, it's important to note that this does not fundamentally define what the OP Stack is. The OP Stack will always be the software that powers Optimism, and it's expected that as Optimism evolves, so will the OP Stack.

The vision behind the OP Stack is to facilitate the creation of highly scalable and interoperable blockchains, and it consists of the many different software components that, together, form the backbone of Optimism mainnet.

A key tenet of OP Stack is its focus on collaboration, which allows anyone to contribute code or components that align with the design principles and goals of the stack. These contributions must satisfy the philosophy of simplicity, pragmatism, sustainability, and Ethereum alignment.

The Three Key Design Principles for Components to Be Added to the OP Stack:

• Simplicity:

With the aim of providing a scalable and flexible L2 solution, Optimism opts for simplicity, giving the stack a number of significant advantages over other more complex L2 constructions.

Ideally, using the minimum number of software components necessary for the stack to function reduces engineering overhead,  allowing more time and effort to be devoted to developing new features instead of duplicating existing ones.

Every line of code has the potential to introduce unintentional bugs, so a leaner, cleaner protocol means fewer bugs and a smaller attack surface, making it easier for external auditors and contributors to review the codebase, which strengthens security.

This is why Optimism prefers to use existing battle-tested Ethereum code and infrastructure where possible. For instance, using Geth (Go-Ethereum), one of the most widely used Ethereum clients, as the foundation for OP Stack’s default execution engine means fewer bugs, faster development, and stronger security.

• Utility:

For any software to be eligible for inclusion in the OP Stack, it should meaningfully contribute to the goals of the Optimism Collective. This ensures that the software will remain not only operational but also competitive over long periods of time.

Op stack’s design process is built around the idea that it contributes to the broader vision of the Optimism Collective (directly or indirectly)

• Extensibility:

Extensibility actively influences Op stack's component design in ways that go hand-in-hand with the idea of collaboration. By keeping the codebase open source and modular, they are able to build a bigger community of contributors who can help maintain the protocol long-term, as collaboration allows the stack to break out of siloed development.

Collaboration  fosters a culture of collective ownership, allowing developers to spend more time building on top of one another's work and less time rebuilding the same components over and over again.

Extensible code means future developers can build and expand on it without needing to rewrite from scratch. In practice, this means that the code should be open source (under a permissive license), expose clean APIs, and generally be modular such that another developer can relatively easily extend the functionality of the code.

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How OP Stack Works?

Optimism Bedrock is the current iteration of the OP Stack. Its job design is simple: make sure all transactions are available and recorded and make sure the resulting state (balances, smart contract changes, etc.) is committed to Ethereum (the base layer).

The OP Stack is modular in nature and it is best to think of it as a collection of software components that are each layers and, when put together, make up the stack. The different layers or modules consist of: Data Availability (DA) Layer, Sequencer, Derivation Layer, Execution Layer and Settlement Layer.

Data availability (DA) Layer

The Data Availability Layer determines where the transaction data inputs for an OP Stack-based chain are published and stored. An OP Stack chain can rely on a single DA module to source its transaction data, but as the chain derives its data from this layer (trustless), the choice of DA module significantly influences the system’s security model.

This matters because if specific data disappears or can’t be accessed, the chain cannot be reconstructed from the Data Availability Layer. This prevents the chain from syncing properly, potentially compromising its functionality and integrity.

The Ethereum DA module is currently the most common Data Availability solution for OP Stack-based chains compared to alternative DA modules (like Celestia or EigenDA). The DA Layer defines where rollups publish their transaction data, and choosing Ethereum DA means input data for the chain can be sourced from any information accessible on the Ethereum blockchain, including Ethereum calldata, events, and EIP-4844 data blobs.

Sequencer

The sequencer is an important layer, as it governs how user transactions on any OP Stack-based chain are collected and submitted. Sequencers are responsible for grouping transactions into batches, compressing them to reduce data and submitting them to the DA Layer module(s) in use.

It functions by collecting user transactions, batching them, and then posting to the DA layer via op-batcher. Op-batcher is the code responsible for periodically reading transaction content from the sequencer and rolling it up onto the chain’s Data Availability (DA).

The sequencer is responsible for giving users fast confirmation and in the current default setup for the OP Stack, sequencing is typically managed by a single dedicated sequencer. However, there are plans to make this configuration modular, allowing chains to switch between multiple preset sequencers, which reduces censorship risk.

The expiry window, defined by a fixed range of L1 blocks during which the sequencer can submit transaction batches, generally limits the Sequencer's ability to censor or withhold transactions beyond a specified time period. This ensures the sequencer can’t hide transactions forever; if the sequencer stalls, others can reconstruct from DA.

Derivation Layer

The Derivation Layer is responsible for processing data from the Data Availability (DA) Layer and converting it into standardized inputs that can be handled by the Execution Layer. This job of translating raw data from the DA layer into execution-ready input is achieved using the standard Ethereum Engine API (the same API used by Ethereum clients like Geth).

Additionally, the Derivation Layer can also reference the current system state, maintained by the Execution Layer, to determine how it parses and interprets the raw input data. In practice, it can be adapted to derive Engine API inputs from many different data sources via the Rollup module and the Indexer module.

The core difference between the Rollup and Indexer modules is the difference between L2 rollups and app-specific rollups. The Rollup module processes data from Ethereum block data, sequencer transaction batches, or deposited transaction events, while the Indexer module processes data based on specific interactions with smart contracts on the Data Availability Layer (Ethereum DA).

Execution Layer

The Execution Layer updates the state of an OP Stack chain. It receives inputs from the Derivation Layer and determines the state transition function (given the current state + a transaction input → here’s the new state).

It applies an additional “L1 Data Fee” to each transaction, covering the cost of publishing that transaction’s data back to Ethereum L1, and changes state whenever the Derivation Layer delivers new inputs through the Engine API.

By abstracting execution in this way, the Stack supports not only the standard EVM but also customized EVM variants or entirely different virtual machines. This makes the OP Stack modular, where chains can innovate at the execution level without redoing the entire stack. For example, the EVM module in the OP Stack’s Ethereum Rollup configuration is a minimally modified EVM that adds support for L2 transactions originating in Ethereum L1 deposits.

Settlement Layer

The Settlement Layer is the mechanism for enabling external blockchains, including other OP Stack chains or third-party chains, to access and verify the state of an OP Stack chain (target).

These mechanism(s) are read-only; they don’t change the state of the chain but offer verified proof of the state of the target, which allows the third-party chain to make decisions using that information, decisions such as processing a withdrawal.

The term comes from the fact that settlement layers are where value exits. For example, to withdraw assets from Optimism on Ethereum, the settlement mechanism offers a snapshot to prove that assets are owned on Optimism, and once Ethereum is convinced, assets are released.

However, Settlement Layers might not be able to verify transactions immediately, and this is because of the finality vs. acceptance paradigm. Although transactions published by the target chain to the DA layer are accepted as final and immutable, the Settlement Layer needs to verify correctness of execution (e.g., via fraud proofs or validity proofs) before accepting the target’s chain state as trustworthy.

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OP Stack Fault Proofs

Most Layer 2s, such as Optimism, assume transactions are valid by default and only perform computations to verify transactions if a dispute is raised. What this means is that transactions are accepted as valid upon settlement on Ethereum unless a dispute is raised.

This approach allows for high throughput and low latency by not requiring every transaction to be verified immediately. Instead, transactions are posted to Ethereum, and there is a mechanism in place for these transactions to be challenged within a certain time frame using fraud proofs.

Similar to our discussion in the Settlement Layer, Fault Proofs or Fraud Proofs allow users to permissionlessly submit and challenge the proposals about the state of an OP Stack chain that are used to prove withdrawals.

Optimism initially decided to go with single-round (non-interactive) fraud proofs for the original implementation of its optimistic rollup. But then, non-interactive fraud proofs displayed limitations, such as the need to store intermediary state roots for transactions on-chain, which was how the dispute smart contract knew which state transition to dispute. They also needed to ensure transactions could be executed within the gas limit of an L1 block because if a disputed state transition required more than 30M gas to re-execute, the on-chain dispute manager contract couldn't settle disputes.

On June 10, 2024, the Interactive Fault Proof System was officially added to the OP Stack and activated on OP Mainnet. This Fault Proofs upgrade brought the OP Stack closer to technical decentralization.

The Fault Proof System consists of three main components:

• A Fault Proof Program (FPP) that runs through the rollup state transition to verify an L2 output from L1 input. This verifiable output can then resolve a disputed output on L1.
• A dispute game protocol enabling participants to narrow down disputing instructions.
• A Fault-Proof Virtual Machine (FPVM).

Cannon is Optimism’s default FPVM. It has two main parts: one in Solidity that verifies MIPS instructions onchain and an offchain Go implementation (mipsevm) for generating proofs.

How Cannon works:

• When a dispute arises, the Dispute Game begins. Participants use bisection to divide the computation into smaller parts, eventually narrowing down from entire state transitions to specific instruction disagreements.
• Then in comes Cannon to run the full computation offchain (using the MIPSEVM), generating a witness proof for that specific disputed instruction.
• The witness proof is submitted and MIPS verifies just this single instruction to settle the dispute definitively.

This combination of off-chain computation and on-chain verification keeps the process efficient and is crucial for cost-effectiveness, given running everything on-chain would be too expensive; thus, most computation happens offchain requiring minimal verification steps to be performed onchain. Additionaly, the introduction of OP Succinct Lite, a zero-knowledge proofs system, gives every OP Stack rollup the ability to become a ZK rollup.

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What is the Superchain ?

The Superchain is a network of chains built on the OP Stack that share bridging infrastructure, decentralized governance, upgrade mechanisms, and a unified communication layer. Bedrock was the first step and the vision of the Superchain is to unify OP Mainnet and other chains into a single, cohesive, collective network of chains.

Instead of creating isolated scaling solutions, Superchain aims to create a more seamless, interoperable ecosystem of chains on a global scale. This would be achieved by running chains in parallel instead of vertical scaling so as to reduce cost and network congestion as well as increase throughput.

Since all OP Stack chains rely on the same bridge contract, this makes Ethereum the common settlement and data availability layer for the entire Superchain. With Ethereum serving this role, any node on any OP chain can check transaction ordering across all OP chains.

In short, OP Chain 1 can verify if a transaction happened on OP Chain 4 by checking Ethereum timestamps. This shared transaction ordering across all chains is essential for keeping the network secure and making chains work well together.

While the Superchain is still a concept and work in progress, the necessary parameters for Optimism to evolve to Superchain:

In order to achieve this goal, Optimism also requires a decentralized security council to govern protocol upgrades and pause withdrawals or upgrades during security concerns.

When these necessary requirements are met, the Superchain architecture is designed to be implemented by a hard fork (coordinated, consensus-breaking changes) across all chains in the Superchain.

To maintain consistency and interoperability, the Superchain enforces strict standardization, meaning experimental OP Stack features may be delayed or excluded until they undergo thorough review and approval.

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The Superchain Ecosystem

Optimism’s Superchain strategy is validated by the Stack’s demonstrated ability to attract a wide range of L2 developers across key verticals. Daily L2 transactions across the 33 publicly announced Superchains live on mainnet have totaled 17.3M and a Total Value Locked (TVL) north of $6 billion as of September 16, 2025.

The most active chains year-to-date are :

• Base: Launched in August 2023, Base is a secure, low-cost, builder-friendly Layer 2 solution on the Superchain, incubated within Coinbase, Base aims to offer a scalable and accessible platform for decentralized applications (dApps), leveraging the security and decentralization of Ethereum while reducing costs and improving transaction speeds. The network accounts for the majority (61.3%) of Superchain transactions in 2025 with 2.4 billion transactions and $4.96 billion in TVL.
• Worldchain: Launched in October 2024 by OpenAI’s Sam Altman. World Chain gives priority to supporting two use cases: anonymous manual verification and financial access. Aiming to differentiate human users from bots, it is part of the broader Worldcoin project, which aims to create a global identity and financial network. The network accounted for 7.7% of Superchain’s transactions so far in 2025 and has $92 million in TVL.
• OP Mainnet: OP Mainnet, previously known as Optimism, is the native chain of Optimism. It is a general-purpose optimistic rollup to provide faster and cheaper transactions while maintaining the security of the Ethereum mainnet. It accounted for 6.9% of Superchain’s transactions in 2025 and a TVL of $439.8 million.
• Soneium: Launched in January 2025, Soneium is a Layer 2 blockchain developed by Sony Block Solutions Labs, a joint venture between Sony Group and Startale. Designed to bridge Web2 and Web3, the network accounted for 6.8% of Superchain’s transactions in 2025 and $89.9 million in TVL.
• Celo: Designed to make DeFi applications and cryptocurrency payments accessible to anyone with a smartphone, Celo is transitioning from a standalone EVM-compatible Layer 1 blockchain to a Layer 2 powered by the OP Stack. With over 215 million in transaction volume, it accounts for 5.3% of Superchain’s transactions in 2025 and currently has $75.6 million in TVL
• Unichain: Launched in October 2024, Unichain is an L2 built by Uniswap and designed for fast, low-cost transactions and cross-chain liquidity. Launched as a rollup, it includes a Trusted Execution Environment (TEE) for transparent block building. The network accounted for 5.2% of Superchain’s transactions in 2025 and $411.4 million in TVL.

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Conclusion

Much of the OP Stack’s success stems from the deliberate advancement of its technical and economic foundations. The tech stack continues to pursue EVM equivalence and introduces as few changes as possible to the Ethereum protocol, thereby maintaining scalability as well as security.

Simultaneously, Optimism Collective’s approach to the Superchain mission has empowered developers to create without worrying about backend infrastructure, a community where technology, investment, and contributions form a self-reinforcing cycle.

This vision is not merely a dream but is being operationalized through a methodical architecture (Bedrock), governance, technology, and retroactive public good funding. The story now represents a broader ambition to redefine interoperability, with Superchain not only primed to emerge as a successful ecosystem but also as a pioneer in how developers can build cross-chain applications without introducing systemic risk and without incurring large overhead.