Fastest Layer 2 sequencer block time
Wall-clock interval between two consecutive newHeads events on each L2 sequencer.
This benchmark measures the live block time of every major Ethereum Layer 2, the actual wall-clock interval between two consecutive newHeads events on the sequencer, not the marketing figure each chain advertises. Arbitrum One leads with sub-second blocks (~250 ms median), built on Nitro's fast-finality fork. Optimism, Base, Blast and Mantle all cluster around the 2 s OP Stack default. zkSync Era, Linea and Scroll show batched cadence with p50 around 3-6 s and a long tail on idle gaps. Taiko's based rollup sits at the 3 s mark. The p99 column reveals stalls 2-3× the nominal block time on every L2, the part marketing pages never quote.
Methodology
We measure the live block time of every major Ethereum L2 by holding a persistent WebSocket subscription to `eth_subscribe("newHeads")` on each sequencer. The harness records T1 when block N arrives and T2 when block N+1 arrives; the sample is wall-clock T2 − T1 in milliseconds. p50 / p90 / p99 are computed via Prometheus `quantile_over_time` over the 24 h window. The histogram bucket boundaries (50 ms → 60 s) cover the full range from Arbitrum's sub-second cadence to zk-rollup batching gaps. Disconnects reconnect with exponential backoff and the natural outlier sample is capped at 5 min so a reconnect can't pollute p50.
Block time by chain
Live p50 over the last 24 hours, ranked lowest first. Each chain has its own consensus mechanism. The explainer below matches what the harness actually measures.
Arbitrum One block time
250 ms p50 over the last 24 hours · Nitro fast-finality, sub-second sequencer.
Blast block time
2.00 s p50 over the last 24 hours · OP Stack fork, 2 s sequencer + native yield.
Base block time
2.00 s p50 over the last 24 hours · OP Stack, 2 s sequencer.
Mantle block time
2.00 s p50 over the last 24 hours · OP Stack fork, modular DA, 2 s sequencer.
Optimism block time
2.00 s p50 over the last 24 hours · OP Stack default, 2 s sequencer.
Taiko block time
2.12 s p50 over the last 24 hours · Based rollup, L1-sequenced by Ethereum validators.
Linea block time
3.83 s p50 over the last 24 hours · zk-rollup, prover-bound cadence.
zkSync Era block time
4.40 s p50 over the last 24 hours · zk-rollup, batched producer.
Scroll block time
9.65 s p50 over the last 24 hours · 97.6% success rate · zkEVM rollup, prover-bound cadence.
Frequently asked
What is the fastest Layer 2 block time?
Arbitrum One leads the leaderboard at sub-second block times, typically 200-300 ms median, occasionally spiking past 800 ms under load. Arbitrum Nitro's fast-finality fork is the reason: it commits blocks every 250 ms by default, far below the 2 s convention used by most OP Stack chains.
Why are Base and Optimism block times so similar?
Base and Optimism both run the OP Stack with the same default sequencer cadence (2 s). Blast and Mantle are also OP Stack forks, their block times cluster identically. The architectural similarity is by design: OP Stack is meant to be a turnkey rollup framework where the sequencer interval is a configuration constant, not a chain-specific design choice.
What is the block time on zkSync Era, Linea, and Scroll?
zk rollups produce blocks in bursts rather than at a fixed cadence. p50 sits around 3-6 s but p90 / p99 can balloon to 15-30 s during idle periods because the sequencer waits for enough transactions to fill a batch before generating the validity proof. The nominal '2 s block time' those chains advertise is the within-burst figure, not the median observed externally.
Is L2 block time the same as L2 finality?
No. Block time measures how often the sequencer produces a block, it's a soft confirmation, reversible if the sequencer decides to. Finality on an L2 means the L1 anchor batch is final on Ethereum, which takes 12-18 minutes (block posting + 12.8 min Casper finality) at best, and 7 days for optimistic rollups under contestation. We track the latter in a separate bench.
How is the L2 block time measured here?
We hold one persistent WebSocket subscription per L2 via `eth_subscribe('newHeads')`. Every new head event is timestamped on receipt and the difference between consecutive events is the block-time sample. p50 / p90 / p99 are computed via Prometheus `quantile_over_time` over the last 24 h. Reconnect artifacts above 5 min are filtered so a network blip can't skew the percentiles.
What about Polygon zkEVM, Mode, Starknet and the rest?
Polygon zkEVM and Mode don't expose a public WebSocket endpoint without an API key, so we defer them to v2 when an API-keyed contributor endpoint lands. Starknet uses the Cairo stack with a different RPC shape, it would live in a dedicated bench rather than be shoehorned into the EVM cohort here. Berachain, Sonic and other adjacent chains are L1s, not L2s, so they live in the l1-finality bench.
Source code github.com/OpenChainBench/OpenChainBench/tree/main/harnesses/l2-block-time
