Arbitrum is a suite of Ethereum scaling protocols, including Arbitrum One (an Optimistic Rollup) and Arbitrum Nova (an AnyTrust chain for high-throughput applications). The platform is designed to offload computation from Ethereum while posting transaction data back to Layer 1. This "rollup" architecture aims to provide faster transaction speeds and lower fees compared to the Ethereum mainnet, without sacrificing the security assurances of the base layer.

The Arbitrum ecosystem has recently implemented significant upgrades to its execution environment and transaction policies:

Arbitrum Stylus (MultiVM): Launched on mainnet in September 2024, Stylus allows developers to write smart contracts in standard programming languages such as Rust, C, and C++, alongside Solidity. This upgrade runs these contracts natively using WebAssembly (WASM), designed to lower gas costs and improve execution efficiency.

Timeboost (Transaction Ordering): In late 2025, the protocol introduced Timeboost, a transaction ordering policy that allows users to bid for an "express lane" for faster transaction inclusion. This feature is designed to capture Maximum Extractable Value (MEV) for the DAO or chain operator while protecting standard users from front-running.

Orbit Chain Expansion: The Arbitrum Orbit framework has seen the deployment of major Layer 3 networks, including ApeChain (launched October 2024), which settles directly to Arbitrum One.

The ARB token is a pure governance asset with specific oversight functions:

DAO Governance: ARB holders vote on core protocol updates, including the adoption of new features like BOLD (Bounded Liquidity Delay) and changes to the constitution.

Security Council Elections: The DAO elects a 12-member Security Council responsible for emergency actions and fast-track upgrades.

Treasury Management: Token holders decide on the allocation of the DAO’s treasury and revenue generated from L3 sequencing fees.

Note: Transaction fees on Arbitrum One and Nova are paid in ETH, not ARB.

Architecture: Optimistic Rollup (Layer 2)

Smart Contract Engine: Stylus (WASM + EVM)

Governance: On-chain DAO (ARB Token)

Initial Supply: 10 Billion ARB (Max 2% inflation/year)