Every comparison
Which one, and why
You want the larger DeFi ecosystem and the deeper liquidity of the two.
Full Arbitrum One pageYou care about the shared stack, because the OP Stack is what Base and several other chains are built on.
Full OP Mainnet pageArbitrum for depth today. Optimism for the bet that many chains sharing one stack beats one big chain, which is already how Base and others were built.
The specifications
| Arbitrum One | OP Mainnet | |
|---|---|---|
| Consensus | Not applicable | Not applicable |
| Throughput | Not applicable | Not applicable |
| Finality | Not applicable | Not applicable |
| Live since | 2021 | 2021 |
| In one line | The largest Ethereum layer 2 by value locked, with the deepest DeFi ecosystem. | The rollup that became a standard. Dozens of other chains run the same code. |
The parts that change the answer
Same model, different code
Both are optimistic rollups settling to Ethereum with a challenge period. Arbitrum runs Nitro, Optimism runs the OP Stack, and the practical difference for a user is close to nothing.
The superchain bet
The OP Stack is designed to be used by many chains, and Base is the largest example. Optimism is betting on that network of chains rather than on its own size.
Liquidity
Arbitrum has more of it and more mature DeFi protocols, which is the difference you will feel when you trade.
Common questions
Are they compatible with each other?
Which is cheaper?
What is the superchain?
Want a second opinion on your own setup?
A comparison page cannot see what you already hold or what you are trying to do. On a call we can, and we will tell you when the honest answer is that it does not matter.