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Solana activates Alpenglow, targeting 150ms finality

Solana activated Alpenglow on mainnet, replacing TowerBFT with direct validator voting designed to cut finality from 12.8 seconds to about 150 milliseconds.

The Top Crypto Editors 2 min read

Solana activates Alpenglow, targeting 150ms finality

Did Solana’s Alpenglow upgrade go live? Yes: on October 21, validators switched the network’s consensus protocol from TowerBFT to Alpenglow, a change designed to reduce transaction finality from about 12.8 seconds to roughly 150 milliseconds. The Solana Foundation’s upgrade page says Alpenglow activated in epoch 1064; consensus moved to the new protocol at slot 459,653,000. That faster finality could let exchanges, banks and merchants treat transactions as settled sooner.

What changed in Solana’s consensus?

Alpenglow replaces TowerBFT’s voting process with direct votes between validators, which are bundled into certificates. According to The Block’s report, citing Anza, the change condenses the previous two-step confirmation process into one. The target is roughly 150 milliseconds to finality, the point at which a transaction can no longer be reversed.

When did validators complete the handoff?

The Foundation says epoch 1064 began at approximately 13:36 UTC, but TowerBFT continued for the first 5,000 slots while validators prepared the transition. Slot 459,652,999 became the genesis block for Alpenglow, certified with votes from 446 of the network’s 654 validators. The new consensus took over from the following slot, and the handoff itself took about 900 milliseconds, according to the Foundation.

What should Solana users and builders watch next?

Transaction execution is unchanged: the Solana Foundation says the SVM, transaction formats and fee mechanics remain the same. The protocol change affects how validators agree on blocks, while vote transactions no longer appear in blocks. Infrastructure that reads block data may need adjustments, including handling multiple candidate blocks per slot and treating “confirmed” and “finalized” as the same state.

The next planned phase is Rotor, which is intended to replace Turbine’s block propagation system with a relay layer. The Foundation says Rotor is not yet scheduled, so its release timing is the next date to watch.

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