Solana's Alpenglow Upgrade Targets Sub-Second Finality

Solana's core developer Anza has started public testnet testing of Alpenglow, a major consensus overhaul. The upgrade targets finality of around 150 milliseconds, down from the current 12.8 seconds.

Alpenglow replaces TowerBFT with a new protocol called Votor, which moves validator voting entirely off-chain to free up block space currently occupied by on-chain vote transactions.

The fast path of Votor finalizes a block in one round when 80% or more of the stake participates. The slow path requires two rounds at 60% stake participation per round and handles notarisation and skip decisions when participation drops below the threshold.

Initial benchmarks show that 96% of blocks achieved fast-path finalization at a median of 214 milliseconds under Alpenglow.