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A

Arbitrum One

Grade
C+

A L2BEAT Stage 1 rollup with permissionless exits — but still a single sequencer.

L2Optimistic rollup
Type
L2 · Optimistic rollup
How it works
Optimistic rollup settling to Ethereum. At Stage 1, users can always withdraw without operator help, a Security Council guards upgrades, and changes face a ≥7-day timelock. BoLD adds permissionless validation.
L2BEAT stage
Stage 1
Node / validator set
Inherits Ethereum security
Sequencer
Single sequencer (Offchain Labs)
Governance
Arbitrum DAO + Security Council
Key risk
Centralized sequencer

Assessment

Arbitrum is one of the most decentralized L2s on paper: L2BEAT Stage 1, forced-exit guarantees and a real DAO. But like every major L2 in 2026 it still runs a centralized sequencer, and the Security Council can act in an emergency — so it is not yet Stage 2.

Decentralized here

  • L2BEAT Stage 1
  • Permissionless exits + 7-day upgrade timelock
  • Active Arbitrum DAO
  • BoLD permissionless validation

Centralization vectors

  • Centralized sequencer
  • Security Council can fast-track upgrades
  • Not yet Stage 2
C+

Verdict

Among the most decentralized L2s — sequencer decentralization is the remaining step.

Visit Arbitrum One →

Grade as of June 2026; an opinionated synthesis of cited public metrics (Chainspect / Nakaflow (Nakamoto), L2BEAT (stages), clientdiversity.org — 2026). Figures shift — see methodology.

Compare Arbitrum One with…

Arbitrum One vs OP MainnetArbitrum One vs StarknetArbitrum One vs Base