Arbitrum

Network Basics

• Arbitrum One is an optimistic rollup — L2 scaling for Ethereum
• EVM equivalent — same tools, wallets, contracts as Ethereum
• ETH is the gas token — not a separate token
• ARB is governance token — not used for gas
• Same addresses as Ethereum — but different network, different balances

Bridging

• Official bridge: bridge.arbitrum.io — most secure
• Deposits (L1→L2): ~10 minutes — after Ethereum confirmation
• Withdrawals (L2→L1): 7 days — optimistic rollup security delay
• Third-party bridges faster — Hop, Across, Stargate, but add risk
• Always bridge some ETH first — need gas on Arbitrum

The 7-Day Withdrawal

• Optimistic rollups assume transactions valid — fraud proofs during 7 days
• Cannot speed up native bridge withdrawal — security requirement
• Plan ahead for exits — don't bridge if you need funds in <7 days
• Third-party bridges use liquidity — faster but fees apply
• Withdrawal can be claimed after 7 days — requires L1 transaction

Gas and Fees

• Much cheaper than Ethereum mainnet — typically 10-50x lower
• Two components: L2 execution + L1 data posting
• L1 data costs can spike — when Ethereum is congested
• Gas prices in gwei — same units as Ethereum
• Fast blocks — ~0.25 seconds

ARB Token

• Governance token — vote on DAO proposals
• Not used for gas — ETH pays for transactions
• Airdropped to early users — claiming period ended
• Staking coming — ARB staking in development
• Available on major exchanges — high liquidity

DeFi Ecosystem

• GMX — largest perps DEX on Arbitrum
• Uniswap, SushiSwap — major DEXs deployed
• Aave, Radiant — lending protocols
• Camelot — native Arbitrum DEX
• Significant TVL — billions in value locked

Wallet Configuration

• MetaMask works natively — add network from chainlist.org
• Chain ID: 42161 — RPC: https://arb1.arbitrum.io/rpc
• Block explorer: arbiscan.io — verify transactions
• Same seed as Ethereum — different network selection

Arbitrum Nova

• Separate chain from Arbitrum One — optimized for gaming/social
• Lower fees than One — less security guarantees
• Different bridge — don't confuse with One
• Chain ID: 42170 — verify you're on correct chain

Stylus

• Run Rust, C, C++ contracts — not just Solidity
• WASM-based execution — alongside EVM
• Coming feature — expands developer options
• Same security as EVM contracts — audited runtime

Common Issues

• "Insufficient ETH for gas" — need ETH, not just tokens
• Wrong network — sent to Arbitrum address on Ethereum (recoverable but complex)
• Withdrawal pending — 7-day wait is normal, not stuck
• Transaction reverted — check slippage, approvals, balance
• "Network not found" — add Arbitrum network to wallet

Sequencer

• Single sequencer currently — Offchain Labs operated
• Centralization concern — decentralization roadmap exists
• Sequencer can't steal funds — only order transactions
• If sequencer down — delayed but not lost, can force include
• Decentralized sequencer coming — DAO governance

Security

• Same security as Ethereum for assets — after 7-day challenge period
• Smart contracts same risks — audit status matters
• Fraud proof protects users — invalid state transitions challenged
• Bridge is secured by Ethereum — L1 is the settlement layer
• Use official bridge for large amounts — third-party bridges add risk