Solana’s Alpenglow upgrade cuts finality to about 150 milliseconds

Solana activated its Alpenglow consensus upgrade on October 21, replacing the voting system it had used since 2020 and targeting transaction finality in about 150 milliseconds. The Solana Foundation’s Alpenglow guide says the upgrade is live on mainnet; CoinDesk reported on the change and its user impact.

How does Alpenglow make transactions final faster?

Alpenglow changes how validators agree that a block’s transactions are final. Under the old TowerBFT system, validators recorded votes as on-chain transactions, and a block became final after enough votes accumulated over 32 slots. The Solana Foundation says that process took about 12.8 seconds.

Alpenglow’s Votor protocol moves those votes off-chain. Validators send votes directly to one another, then combine them into certificates. A block can become final after one or two rounds of voting. Think of it as replacing a growing stack of separate approvals with a shared certificate. The transaction still runs through Solana as before; the agreement about whether it can be reversed happens sooner.

The switch took effect at slot 459,653,000 in epoch 1064. The Foundation says 150 milliseconds is the target for finality, not a guarantee for every transaction. It is also separate from block time, which was reduced in a different upgrade.

What changes for someone sending a payment?

Wallets and apps continue to work as before, and users do not need to take action. The Foundation says transaction execution and fees are unchanged. The potential benefit is that a service can treat a payment as settled sooner. An exchange could credit a deposit earlier, or a merchant could release a purchase sooner, because the wait for finality is shorter.

The improvement is in the network’s settlement step, not in how quickly every app displays a confirmation. CoinDesk notes that the service handling a payment affects when finality information reaches a user. So the 150-millisecond target does not mean every wallet screen will update in that time.

Why might Solana’s transaction counts drop?

Alpenglow removes validator votes from the blockchain’s transaction records. Dashboards that counted those votes may therefore show fewer transactions after the upgrade, even if user payments and trades continue at the same pace. The Foundation advises services that report transaction counts to adjust their metrics for the change.

For most users, the visible change is meant to be faster settlement without a new wallet or a different way to send funds. The underlying consensus mechanism has changed; the basic transaction experience has not.

Sources and documents

• Solana Foundation’s Alpenglow guide — solana.com
• reported on the change and its user impact — coindesk.com