The brief

Analyst view

• Arbitrum One is the largest optimistic rollup, supporting over 7,000 tokenized real-world assets with $1B+ TVL in RWAs alone.
• BoLD, the permissionless fraud proof system, went live in early 2025, enabling any node operator to challenge invalid state roots.
• Arbitrum Stylus, launched in 2024, lets developers write smart contracts in Rust, C, and C++ via WebAssembly, expanding beyond Solidity.

Technical approach

As reported

Nitro

Optimistic rollup engine

Nitro batches transactions on Ethereum for settlement, enabling lower fees and faster throughput than L1.

BoLD

Permissionless fraud proofs

BoLD enables any node to challenge invalid state claims without permission from Offchain Labs, moving Arbitrum toward Stage 2 security (fully trustless).

Stylus

WebAssembly smart contracts

Stylus lets developers write contracts in Rust, C, and C++, compiled to WebAssembly instead of Solidity. Programs run faster and use less gas.

Orbit

L3 framework

Arbitrum Orbit lets developers launch their own L3 chains (app chains or rollups) that settle to Arbitrum One, with customizable throughput and fees.

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