Arbitrum

Arbitrum is a Layer-2 scaling technology for Ethereum developed by Offchain Labs. Its core product, Arbitrum Rollup, is an Optimistic Rollup protocol that executes and batches transactions off the Ethereum mainnet and posts them back to Ethereum, which serves as the checkpoint and security layer. Optimistic rollups assume off-chain transactions are valid and rely on a fraud-proof mechanism on Layer 1; the system remains secure as long as at least one honest validator participates. Arbitrum provides near-complete Ethereum Virtual Machine compatibility, so existing Solidity or Vyper contracts and Ethereum tooling work without rewriting code.

The platform operates multiple chains. Arbitrum One is the flagship optimistic rollup chain, launched to mainnet in 2021. Arbitrum Nova, launched in 2022, uses the AnyTrust protocol, which adds a Data Availability Committee trust assumption to lower costs further and is oriented toward gaming, NFT and social applications; committee members have included ConsenSys, QuickNode, P2P.org, Offchain Labs, Google Cloud and OpenSea. Beyond the public chains, Arbitrum offers tooling for teams to deploy dedicated chains with configurable execution, gas tokens, data availability, governance and validation, plus Stylus, which allows EVM-compatible contracts written in Rust, C and other languages that compile to WebAssembly. Documentation covers node operation (full, archive, feed relay, Data Availability Server) and bridging of ETH and ERC-20 tokens between Ethereum and Arbitrum chains.

Governance of the protocol sits with the Arbitrum DAO, established alongside the March 2023 launch of the ARB token. Offchain Labs continues as the research and development team behind the network.

Founding story

The Arbitrum concept originated at Princeton University, where Harry Kalodner and Steven Goldfeder were graduate students in 2014 and the idea began as a class project. Together with Ed Felten — a Princeton computer science and public affairs professor and former deputy U.S. Chief Technology Officer in the Obama administration — the three developed the Arbitrum technology at Princeton and published a paper in 2018. That year they founded Offchain Labs to commercialize the technology with the aim of scaling Ethereum.

Business model

Arbitrum operates public blockchain networks (Arbitrum One and Arbitrum Nova) on which users pay transaction fees, and provides SDKs and infrastructure for third parties to launch dedicated Arbitrum chains. The network is governed by the Arbitrum DAO, which holds the largest single allocation of the ARB token supply, while Offchain Labs serves as the research and development organization behind the technology.

Traction

At the Arbitrum One mainnet launch, over 400 dApps including Aave, Balancer, Curve, SushiSwap and Uniswap were reported as using or planning to use the network. Reddit built its Community Points rollup on Arbitrum technology. Reported total value locked was about $965 million in October 2022 and over $2.3 billion in March 2025.

Latest developments

In March 2025, Offchain Labs announced a phased plan to acquire ARB tokens from the open market and other transactions to build its treasury, without disclosing target volumes or timeframe, framed as support for ecosystem expansion including Arbitrum BoLD, Orbit and Stylus. Current documentation positions Arbitrum as a finance-native platform for applications, tokenization and dedicated chains, and directs developers to reactivate Stylus contracts to keep them callable.