Optimism is an optimistic rollup on Ethereum, and also the name of the collective behind the OP Stack: the open-source framework that OP Mainnet, Base and many other chains are built on. Building for Optimism therefore often means building for a whole family of compatible chains, the Superchain.
How OP Mainnet Works
A sequencer orders transactions and produces blocks quickly. Transaction data is posted to Ethereum, and results are final on Ethereum after a challenge period during which anyone can dispute them with fault proofs. For users, that means low fees and fast confirmations on the rollup, and withdrawals to Ethereum through the standard bridge that take about a week. OP Mainnet is EVM-equivalent, so Solidity contracts and Ethereum tooling work without changes.
What We Build
- dApps and contracts deployed on OP Mainnet and other OP Stack chains with identical addresses and configuration.
- Fee handling: OP Stack fees include an L1 data fee next to execution gas; we estimate both so transactions neither fail nor overpay. See EIP-1559.
- Bridging: deposits, withdrawals and messages between Ethereum and OP Stack chains, and the user experience around waiting times. See cross-chain bridges.
- Gasless and smart account flows, see account abstraction.
Your Own OP Stack Chain?
The OP Stack lets organisations launch their own chain, often through a rollup-as-a-service provider. That brings control over throughput, fees and upgrades, but also the cost of running and securing a chain and the challenge of attracting users and liquidity. For most products, deploying on an existing chain is the better start; we help you assess when your own chain is worth it.
Frequently Asked Questions
What is the difference between Optimism and Base?
Both run the OP Stack. OP Mainnet is governed by the Optimism Collective; Base is run by Coinbase and focuses on consumer apps. Code usually runs on both.
Why do withdrawals take a week?
Optimistic rollups allow time for anyone to challenge an invalid result. Fast bridges let users skip the wait by providing liquidity.
What is the Superchain?
The network of OP Stack chains that share standards and upgrades, aiming for easy interoperability between them.
Who owns the code?
Ownership of the source code is set out in the contract, and the code can be fully yours, including documentation and tests.
Part of our layer 2 development. Compare Arbitrum and zkSync.
Build on Optimism
Tell us which OP Stack chains matter for your product. We will build and deploy it across them.