Base or Arbitrum: which to build on
How the two largest L2s differ in architecture, ecosystem and everyday usage, and what that means for where you deploy.
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Both are optimistic rollups on Ethereum. Both are cheap and fast enough that the difference stopped mattering to most users a while ago. The comparison is really about what got built on each and who turned up.
The live numbers sit alongside this and update on their own. This is the part that does not change every ten minutes.
Different stacks
Base runs on the OP Stack, the shared codebase behind Optimism and a growing set of other chains. Arbitrum runs Nitro, which it built itself.
The practical difference for a user is close to nothing. Both are EVM chains where the same contracts and tools work. The difference for the ecosystem is larger: Base shares upgrades and infrastructure with every other OP Stack chain, while Arbitrum controls its own roadmap entirely.
Both are at Stage 1 on L2Beat's maturity scale, meaning fraud proofs are live but a security council can still intervene.
Different ecosystems
Arbitrum arrived first and grew a deep DeFi ecosystem, with a strong concentration of derivatives and trading protocols. Much of that is still there and still mature.
Base grew through consumer applications and Coinbase's distribution. Its DeFi is concentrated in fewer, larger protocols, with lending dominant and Aerodrome routing most of the spot trading. Its social and creator applications have no real Arbitrum equivalent.
If you are looking for a particular protocol, check where it actually is. Most large protocols are on both, but rarely with the same liquidity.
The gap in usage
This is where the two have diverged most. Base carries several times Arbitrum's daily active addresses and transactions.
Some of that is Coinbase routing users straight onto the chain, which is a distribution advantage no other L2 has. Some of it is that consumer applications generate many more transactions per user than DeFi does.
It is worth being careful about what active addresses measure. One person can hold many addresses, and a single contract can serve thousands of people. The number tracks activity, not population.
Choosing
For most people the question does not arise, because the application decides. You use whichever chain the thing you want is on.
If you are deploying something, the honest split is that Arbitrum has the deeper DeFi liquidity and Base has the users and the distribution. Neither gap is permanent, and both have narrowed before.
Frequently asked
- Which is bigger, Base or Arbitrum?
- It depends what you measure. Base carries far more daily activity, with several times Arbitrum's active addresses and transactions, and holds more value locked. Arbitrum has the longer history and a deeper set of mature DeFi protocols. The live numbers are on the comparison page.
- Are Base and Arbitrum both rollups?
- Both are optimistic rollups on Ethereum, but they are built differently. Base runs on the OP Stack and Arbitrum on Nitro, and the fraud proof systems differ. Both currently sit at Stage 1 on L2Beat's maturity scale.
- Is one cheaper than the other?
- Base has generally had the lower median transaction fee, though both are cheap enough that cost rarely decides anything for an ordinary user. The comparison page shows the current figures for each.