Arbitrum
The largest Ethereum optimistic rollup by DeFi TVL, with the deepest onchain derivatives liquidity.
Arbitrum One is an optimistic rollup built by Offchain Labs, using Arbitrum Nitro for execution and posting fraud proofs to Ethereum. It is L2BEAT Stage 1 with BOLD permissionless validation live since late 2025, meaning any participant can challenge an invalid state. Deep DeFi and perpetuals liquidity (GMX, Aave, Radiant, Camelot) make it the default L2 for onchain derivatives and leveraged strategies.
- TVL around $13.8–16.9B in April–May 2026 per L2BEAT and DeFiLlama, roughly 38–44% of all Ethereum L2 DeFi.
- Stage 1 rollup with BOLD permissionless fraud proofs (live since February 2025); ~250ms soft confirmations, ~12s L1 batch cadence, 7-day withdrawal challenge window.
- Native ETH gas, sub-cent typical fees post-Dencun, and full EVM equivalence via Nitro.
- Major lending venues live: Aave V3, Compound V3, Morpho, Radiant, Silo, plus GMX and Camelot for perps and DEX liquidity.
- The Arbitrum DAO governs a treasury measured in the billions of ARB and directs incentive programs like STIP and LTIPP that periodically bootstrap DeFi TVL.
Frequently asked questions
Is Arbitrum a rollup or a sidechain?
Arbitrum One is a true optimistic rollup: transaction data is posted to Ethereum via blobs, state can be challenged by anyone, and security ultimately settles on Ethereum. It is not a sidechain, which would have its own independent validator set.
How long does a withdrawal from Arbitrum to Ethereum take?
Native canonical withdrawals take approximately 7 days because of the optimistic fraud-proof challenge window. Third-party fast bridges (Across, Stargate, Orbiter) let you exit in minutes for a small fee by fronting the funds on L1 and being repaid when the canonical withdrawal completes.
Why is Arbitrum popular for lending yields?
Deep liquidity and mature audited protocols mean lower slippage, more stable rates, and more collateral choices than smaller L2s. Governance-directed incentive programs periodically boost supply APY, and Arbitrum's connection to onchain derivatives (GMX, Vertex) creates borrow demand that supports supplier rates.