Optimism Shared Node

Optimism (or Optimistic Ethereum) is one of the implementations of the Optimistic Rollups, mainstream L2 Ethereum (ETH) scaling design. Created by Optimism Public Benefit Corporation (PBC), it allows Ethereum (ETH) users and dApps to access Ethereum (ETH) on higher speed with significantly reduced gas fees.

Optimism is connected to Ethereum’s main network (Optimistic Mainnet) and test network (Optimistic Kovan). Despite being in its nascent stage, Optimism is already integrated by Uniswap v3, the largest Ethereum-based decentralized exchange.

Just like other Layer-2 Ethereum (ETH) scalability designs, Optimism ‘keeps Ethereum half-full’ by partially processing transactional data off-chain. The transactions are rolled up in ‘batches’: multiple transactions are included similarly to the single one. Optimism doesn't do computations: its mechanisms just broadcast new ‘state’ (like a snapshot of network condition) to Ethereum’s mainnet.

Optimism ensures that the entire procedure is fair by a ‘fraud-proof’ mechanism: if someone deems a certain transaction to be fraudulent, he/she can challenge it.

Ethereum (ETH) scaling refers to a number of various techniques designed to overcome major bottlenecks of the largest smart contract platform. As Ethereum (ETH) is the most popular hosting platform for decentralized applications, its throughput (speed, gas efficiency, transactional bandwidth) limitations are amplified by the periods of high network overload.

Ethereum (ETH) scaling solutions unload some transactional data from Ethereum (ETH) mainnet. For instance, Plasma-based solutions (e.g. early Polygon) merges the data about multiple transactions in a single batch. Celer and Raiden process data through payment channels (like Bitcoin’s Lightning Network).

Validium solution also utilizes zero-knowledge rollups (ZK-rollups) to save on computational power, but it doesn’t store the data on Ethereum’s Layer1 (mainnet or testnet). So does Arbitrum, a solution focused on scalability for DeFi protocols.

Both Validium and Arbitrum live in alpha testnets, so they are less battle-tested and still need more research.

Optimism is the safest technical design for Ethereum (ETH) scaling: ‘fraud-proof’ mechanism prevents malicious transactions from being included into the batch for broadcasting to Ethereum mainnet.

Also, Optimism is a viable alternative to first-gen scaling solutions due to its 100% compatibility with Ethereum Virtual Machine (EVM) and Solidity programming language: every dApp deployed to Ethereum (ETH) can be also deployed to Optimism with no extra engineering expertise.

Optimism doesn’t execute transactional computation itself, so Ethereum's security is Optimism security as well. Optimism’s design is more aligned with sharding, a modular architecture of much-anticipated Ethereum 2.0.

At the same time, Optimistic Rollups work slower than ZK-Rollups like Loopring, Aztec, Starkware.

So far, Optimism is the only Layer-2 scaling solution for Ethereum (ETH) that calculates and displays its efficiency statistics. As of Q3, 2021, according to Chainlink-powered oracles, it reduces gas consumption by the factor of 10,8x.