Rollup

ARB is the delegated governance token for Arbitrum One and Nova, but it neither pays their gas nor runs their sequencers. Its history is a map of divided authority among the DAO, Foundation, validators, upgrade executors and a 9-of-12 Security Council.

Optimism grew from OP Mainnet into the OP Stack and Superchain: shared code, upgrades, governance and chain revenue. OP votes and now sits beside a treasury buyback program, but it does not pay gas or grant a fixed share of fees; fault proofs remain bounded by a single sequencer and fast upgrade keys.

Starknet is a general-purpose Ethereum validity rollup whose Cairo execution is proven with STARKs and settled through Ethereum contracts. It is separate from StarkEx, StarkWare’s application-specific scaling service. STRK now pays all Starknet transaction fees, supports delegation and phase-2 validator attestation, and carries protocol voting power; it is not equity or a claim on StarkWare or the Foundation. The network has distributed sequencing components and a live S-two prover, but block production, proving and upgrade control have not yet reached the permissionless end state described in its roadmap.

ZKsync developed from Lite’s Ethereum payments into Era and a network of public and permissioned chains. Its ZK token governs upgrades and token programs; Lite’s 2026 closure, a paused staking pilot and the planned EraVM transition show how much remains in motion.

Yaoqi Jia’s AltLayer began with disposable rollups for short bursts of demand, then proposed VITAL, MACH and SQUAD to add restaked security to application chains. MACH reached mainnet deployments and ALT gained staking uses, but operators, MACH administrators and the token-owner Safe still hold distinct powers. By 2026 the company had also moved into on-chain AI agents.