Solana activates Alpenglow, targeting transaction finality in about 150 milliseconds
Key Facts
Solana activated the Votor phase of its Alpenglow upgrade on its mainnet on October 21, 2026, according to the Solana Foundation, aiming to shorten the wait for transactions to be irreversibly confirmed. The upgrade targets transaction finality in about 150 milliseconds under normal network conditions, according to documentation from Anza, which presented the consensus system's design. That time refers to a transaction being committed to the network's ledger, while the timing of deposit availability at exchanges and intermediaries falls outside this target. Anza said the "confirmed" and "finalized" statuses have become equivalent under Alpenglow, carrying the same meaning for a transaction. Both mean the transaction has been "permanently committed to the ledger," it said in its documentation, a change that determines when a transaction's outcome becomes final on the network.
In its original design comparison, Anza cited a historical time of about 12.8 seconds between block creation and finality under the previous Tower BFT consensus system. The company contrasted that with a target median time of about 150 milliseconds for Alpenglow in the comparison it presented when explaining the new design. The original latency estimates were based on simulations of the mainnet stake distribution, excluding computational overhead, according to Anza. But finality under the previous system had already shortened before the upgrade's activation as the network reduced slot duration. Galaxy said Tower BFT finality was approaching 6 seconds with 200-millisecond slots on the eve of activation, putting the more recent comparison at a different level from the historical benchmark Anza presented.
The operational change moves validator votes from transactions submitted on-chain to messages exchanged directly between validators, according to the Solana Foundation. Once sent, these votes are aggregated into certificates under the new consensus mechanism the upgrade introduced to mainnet. Describing the mechanism, the foundation said validators "now send votes directly to one another and aggregate them into certificates." On fault tolerance, Anza describes Alpenglow's design as capable of tolerating malicious stake of up to 20%. The design also tolerates an additional 20% of unresponsive stake alongside the malicious stake, according to the company's explanation of the consensus architecture.
The move to mainnet followed community testing that included restarting the chain from genesis 6 times, according to Galaxy, which participated in those tests. These operations involved restarting the chain from a new genesis block during pre-launch testing. Galaxy said the tests also included a failed network-wide transition attempt and a rollback. For validators operating under Alpenglow, Anza's documentation specifies an admission ticket of 0.8 SOL per epoch. The ticket's value is burned from the validator's vote account, becoming a recurring requirement for participation. If the account balance is insufficient to cover it, the validator is barred from voting in the next epoch. An insufficient balance also prevents the validator from producing blocks during that epoch, according to Anza's vote account guide.
In the market, Investing's historical price table for Solana showed a daily gain on the activation date, October 21, 2026. The recorded price for that day was 106.930, according to the table tracking the token's moves as the upgrade launched. The daily gain reached 0.39% that day. By comparison, the table recorded a price of 106.514 on October 20, 2026, the day before Alpenglow's mainnet activation. The daily gain in the session before activation was 1.40%, larger than the increase recorded on the upgrade's launch day.
Alpenglow's subsequent phase, called Rotor, will address block data distribution, according to the Solana Foundation. This phase replaces the Turbine mechanism used to distribute that data across the network. The foundation has not set a launch date for Rotor, which remains outside the scope of the currently activated Votor phase. On network use after activation, the foundation said wallets and applications "work exactly as they did before." It also confirmed that the Solana Virtual Machine, transactions, programs and fees remain as before, with the current change limited to the consensus and voting mechanism.