Arbitrum is an Ethereum layer-two scaling solution that strives to enhance the speed and lower the cost of transaction processing of Ethereum. It seeks to achieve this via optimistic rollups which move most of the protocol's computation and storage load off-chain. The native token of Arbitrum is ARB, which is used for governance. The developers behind Arbitrum, Offchain Labs, have transitioned to a decentralized autonomous organization (DAO) structure, known as the Arbitrum DAO. ARB holders can vote on proposals that influence the features, protocol upgrades, funds allocation, and election of a Security Council.

Arbitrum operates using optimistic rollups, a technology that aims to increase the scalability of Ethereum. It supports unmodified Ethereum Virtual Machine (EVM) contracts and transactions, meaning existing Ethereum decentralized applications (DApps) can run on Arbitrum without any code changes. Arbitrum aims to handle a high number of transactions per second, thereby seeking to lower fees and increase the speed at which transactions are finalized. It also allows developers to deploy programs written in popular programming languages like Rust, C++, and more using Stylus, its upcoming EVM+ equivalence feature. Arbitrum does not rely on any centralized operator or sequencer to order transactions. Instead, it uses a decentralized network of validators who stake ARB tokens and are compensated for securing the network.

Arbitrum - through its optimistic rollups - aims to provide a more scalable and cost-efficient platform than Etherium layer one for developers to build and deploy Ethereum-compatible DApps. This positions it as a potential solution for developers who aim to overcome the scalability and cost issues associated with Ethereum. Additionally, with its upcoming EVM+ equivalence feature, Stylus, Arbitrum seeks to enable developers to deploy programs written in popular programming languages like Rust, C++, and more. The ARB token, used for governance, allows holders to vote on proposals that affect the features, protocol upgrades, funds allocation, and election of a Security Council, thereby influencing the future direction of the Arbitrum ecosystem.

Arbitrum was developed by Offchain Labs, a New York-based development company founded by Ed Felten, Steven Goldfeder, and Harry Kalodner, former Princeton University researchers with extensive experience in computer science, cryptography, and blockchain. In 2021, Offchain Labs raised funds in its latest Series B funding round, led by Lightspeed Venture Partners, valuing the company at a certain amount. The Arbitrum DAO was announced as a shift towards a decentralized governance structure, with the ARB token serving as the governance token. In March 2023, Arbitrum announced an airdrop of ARB tokens to early users and DAOs building on Arbitrum. The token generation event took place on March 23, 2023. Arbitrum has a roadmap for 2023.