Arbitrum vs Optimism

Side by side OpenChainBench measurements. Identical layout for both providers, no editorial verdict, no winner badge. The numbers below come straight from the same Prometheus queries that drive the parent benchmark pages.

Read methodology Last measured Fri, 12 Jun 2026 10:19:24 UTCWindow: rolling 24h1 shared benchmark

Arbitrum

Optimistic rollup built on Nitro stack with a fast-finality sequencer. Sub-second block times (~250 ms) via a 250 ms default block interval, far below the 2 s OP Stack convention. 7-day fraud-proof window for L1 finality.

Optimism

Optimistic rollup and the canonical OP Stack reference implementation. 2-second sequencer block time, 7-day fraud-proof window, anchored to Ethereum L1 via batch submissions to the Optimism Portal.

Side by side measurements

Fastest L2 block time, live across Arbitrum, Base, Optimism and 6 more

Blockchains

Arbitrum

249 ms

p99: 359 ms
rank: #1
samples: 341,744

Optimism

2.00 s

p99: 2.08 s
rank: #2
samples: 42,819

How this pair was selected

A pair is published when all four conditions hold. Both providers run in the same OpenChainBench benchmark for at least seven consecutive days. Each provider has at least 1000 samples in the measurement window. The head to head query has observable third party search demand. Both providers have a public /products/[slug] page on OCB. The full pair ledger is versioned in the public repo so the methodology is externally verifiable.