Rollup Stacks
OP Stack

OP Stack

Optimism Bedrock is the current iteration of the OP Stack. The Bedrock release provides the tools for launching a production-quality Optimistic Rollup blockchain. The OP Stack serves as a comprehensive framework designed to simplify and secure the development of Layer 2 (L2) scaling solutions.

According to the layer 2 statistics (opens in a new tab), the OP Stack is being used as a backbone to power 6 active projects — OP Mainnet, Blast, Base, Mode Network, Kroma, and Zora — with collectively secured TVL value of 13.6 Billion USD.

Optimism Bedrock benefits

Lower fees

In addition, Bedrock implements an optimized data compression (opens in a new tab) strategy to minimize data costs. We are currently benchmarking the impact of this change, but we expect it to reduce fees significantly.

Bedrock also removes all L1 execution gas, reducing L1 data fees to the theoretical minimum. This reduces fees by an additional 10% over the previous version of the protocol.

Shorter deposit times

Bedrock introduces support for L1 re-orgs in the node software, which significantly reduces the amount of time users need to wait for deposits. Earlier versions of the protocol could take up to 10 minutes to confirm deposits. With Bedrock, we expect deposits to confirm within 3 minutes.

Improved proof modularity

Bedrock abstracts the proof system from the OP Stack so that a rollup may use either a fault proof or validity proof (e.g., a zk-SNARK) to prove correct execution of inputs on the rollup. This abstraction enables systems like Cannon (opens in a new tab) to be used to prove faults in the system.

Improved node performance

The node software performance has been significantly improved by enabling execution of several transactions in a single rollup "block" as opposed to the prior "one transaction per block" model in the previous version. This allows the cost of merkle trie updates to be amortized across multiple transactions. At current transaction volume, this reduces state growth by approximately 15GB/year.

Node performance is further improved by removing technical debt from the previous version of the protocol. This includes removing the need for a separate "data transport layer" node to index L1, and updating the node software to efficiently query for transaction data from L1.

Improved Ethereum equivalence

Bedrock was designed from the ground up to be as close to Ethereum as possible. Multiple deviations from Ethereum in the previous version of the protocol have been removed, including:

  1. The one-transaction-per-block model.
  2. Custom opcodes to get L1 block information.
  3. Separate L1/L2 fee fields in the JSON-RPC API.
  4. A custom ERC20 representation of ETH balances.

Bedrock also adds support for EIP-1559, chain re-orgs, and other Ethereum features present on L1.

OP Stack and Superchain

The OP Stack is the set of software that powers Optimism — currently in the form of the software behind Optimism Mainnet and eventually in the form of the Optimism Superchain and its governance.

The OP Stack of today was built to support the Optimism Superchain (opens in a new tab), a proposed network of L2s that share security, communication layers, and a common development stack (the OP Stack itself). The Bedrock release of the OP Stack makes it easy to spin up an L2 that will be compatible with the Superchain when it launches.