Last Updated: March 2026
Arbitrum is the largest Ethereum Layer 2 by total value locked — processing more DeFi activity than most L1 blockchains. It uses optimistic rollup technology to offer Ethereum security with dramatically lower fees and faster transactions.
History
Built by Offchain Labs, founded by Steven Goldfeder, Harry Kalodner, and Ed Felten (former White House Deputy CTO). Launched in 2021. ARB token airdropped in March 2023 to early users. Arbitrum quickly became the dominant L2 by TVL, hosting major DeFi protocols. See L2 guide and airdrop guide.
Key Products
- Arbitrum One: Main chain — optimistic rollup with Ethereum security. 250ms block times, sub-cent fees
- Arbitrum Nova: Ultra-low-cost chain for gaming and social (AnyTrust technology)
- Arbitrum Orbit: Framework for launching custom L3 chains on top of Arbitrum
- Stylus: Write smart contracts in Rust, C, C++ (not just Solidity). See smart contract guide
DeFi Ecosystem
Arbitrum hosts the most active L2 DeFi ecosystem:
- GMX: Largest perpetual DEX. See GMX guide
- Aave, Uniswap, Curve: All major Ethereum DeFi deployed on Arbitrum. See Aave, Uniswap, Curve
- Camelot: Arbitrum-native DEX
- Pendle: Yield trading. See Pendle guide
Tokenomics
ARB: 10B total supply. Governance: Arbitrum DAO controls treasury and protocol upgrades. Treasury: Billions in ARB for ecosystem grants. See tokenomics and DAO guide.
Arbitrum vs Base vs Optimism
- Arbitrum: Largest TVL, most DeFi protocols, Stylus multi-language support
- Base: Coinbase backing, fastest growth, consumer app focus. See Base guide
- Optimism: OP Stack powers Base/Mode/Zora (Superchain vision). See OP guide
Pros and Cons
- Pro: Largest L2 by TVL and DeFi activity
- Pro: Stylus enables Rust/C/C++ smart contracts
- Pro: Orbit enables custom L3 chains
- Pro: Former White House deputy CTO as co-founder
- Con: 7-day withdrawal to Ethereum (optimistic rollup)
- Con: ARB token utility is primarily governance
- Con: Competition from Base (growing faster) and ZK-rollups
Frequently Asked Questions
Is Arbitrum safe?
Arbitrum inherits Ethereum’s security. Your funds can always be withdrawn to L1 even if Arbitrum goes offline. Smart contract risks on individual dApps apply. See security guide.
How do I use Arbitrum?
Add Arbitrum to MetaMask, bridge ETH (or withdraw directly from exchanges), and interact with dApps. See MetaMask guide and bridge guide.
