Solana activates Alpenglow consensus upgrade to speed transaction finality
Solana has transitioned its mainnet to the Alpenglow consensus protocol, retiring the TowerBFT mechanism in place since 2020 and targeting sub-second settlement times of around 150 milliseconds.
Solana migrated its mainnet to the Alpenglow consensus protocol on Oct. 21, replacing TowerBFT, the network's consensus engine since its 2020 launch. Anza, the engineering firm behind Solana's Agave validator client, announced the switch shortly after the network processed its final TowerBFT block at slot 459,652,999 at roughly 13:54 UTC, with the official Solana account confirming activation minutes later.[1][7][8][9]
The upgrade is designed to cut transaction finality down to roughly 150 milliseconds, dropping sharply from TowerBFT's original 12.8-second mark. Under Alpenglow, confirmed and finalized states become equivalent, intended to speed settlement for financial applications and trading without requiring users to change wallets. Early network metrics reported by SolanaFloor showed observed finality falling as low as 394 milliseconds shortly after activation.[1][2][4][6][9]
The transition specifically implements Votor, overhauling how validators cast ballots. Rather than submitting votes as standard on-chain transactions, nodes exchange BLS-signed messages aggregated into certificates, which can finalize blocks in a single round if 80% of stake agrees. This mechanism eliminates vote spam that previously accounted for about three quarters of Solana's transaction traffic, shifting validators from per-vote fees to a flat fee of 0.8 SOL per epoch.[3][5][9]
Key facts
- Solana activated the Alpenglow consensus upgrade on mainnet on Oct. 21, 2026, retiring the TowerBFT system used since 2020.
- The upgrade was developed by Anza and targets transaction finality of roughly 150 milliseconds.
- The final TowerBFT-era block was slot 459,652,999 at roughly 13:54:00 UTC before the chain switched to Alpenglow.
- Under Alpenglow's Votor voting engine, validators send BLS-signed messages aggregated into certificates instead of on-chain vote transactions.
- Voting validators now pay a flat fee of 0.8 SOL per epoch instead of submitting per-vote fees.
- A block can finalize in one round if 80% of active stake votes for it, or two rounds at 60% stake.
Sources · 9 sources
- CR
CryptoSlateArticle ·
Solana targets faster finality, while Wall Street cuts the cash that must move Solana activated Alpenglow on mainnet on Oct. 21 at slot 459,653,000, replacing TowerBFT with a consensus design that targets about 150 milliseconds to finality. Under the new protocol, confirmed and finalized become the same state. At the National Securities Clearing Corporation (NSCC), multilateral netting cuts the value of equities payment obligations by an average of… Read the full story on CryptoSlate Understand the crypto stories that matter and what to watch next. Get The Catalyst in your inbox
Open source - TB
The BlockArticle ·
Anza’s Alpenglow goes live on Solana, cutting finality to 150 milliseconds Solana activated Alpenglow, replacing TowerBFT and cutting transaction finality from 12.8 seconds to about 150 milliseconds.
Open source - TW
The Wolf Of All Streets@scottmelkerPost on X ·
Solana's biggest network overhaul since 2020 is live: Alpenglow targets 150ms finality "Solana's Alpenglow, biggest network overhaul since 2020, goes live Wednesday. I can update that, it went live because it is Wednesday and it just happened a couple of hours ago." "Alpenglow will replace the voting system Solana has used since 2020, targeting roughly 150 millisecond finality. I just blinked and I missed it." "It's replacing Tower BFT with the Votor validator voting system." "When we talk about high frequency trading, all those things, this takes it down to milliseconds, literally faster than you can blink."
Open source - CO
CoindeskArticle ·
Solana’s biggest network change since 2020 is live. Here’s how users benefit The new voting system targets settlement in about 150 milliseconds, potentially shortening waits for payments and deposits. Users can keep their existing wallets.
Open source - LD
Lark Davis@LarkDavisPost on X ·
Solana Alpenglow is now live on mainnet. What it actually does: - Kills TowerBFT and slashes finality from ~12.8s to ~150–200ms - Replaces on-chain vote transactions with direct BLS voting (Votor) - Frees up massive block space previously eaten up by validator vote spam - Gives true irreversible, Web2-level settlement for trading and payments TLDR: Solana was fast, now it has afterburners. Plus validators save ~60% on vote fees, and less block congestion means lower priority fee spikes during hype runs. Send it.
Open source - SO
SolanaFloor@SolanaFloorPost on X ·
🚨BREAKING BIG: Alpenglow, @Solana’s biggest consensus upgrade in history, is now live on mainnet. Transaction finality has dropped as low as 394ms from 12.8 seconds, https://t.co/Zmm9HoDOGq
Open source - DE
DecryptArticle ·
Solana Alpenglow Goes Live in 'Most Ambitious' Upgrade Since Ethereum's Merge The new consensus protocol retires TowerBFT, which had run Solana since its 2020 launch, after a handoff on the live network.
Open source - CO
CoinGape@CoinGapeMediaPost on X ·
⚡️ Today's #BrandPulse 🚨 𝗦𝗼𝗹𝗮𝗻𝗮’𝘀 𝗔𝗹𝗽𝗲𝗻𝗴𝗹𝗼𝘄 𝗧𝗮𝗿𝗴𝗲𝘁𝘀 𝟭𝟱𝟬𝗺𝘀 𝗙𝗶𝗻𝗮𝗹𝗶𝘁𝘆 @anza_xyz , the engineering firm behind @Solana’s Agave validator client, is advancing network #performance and #security. Its #Alpenglow upgrade went live on #mainnet-beta on October 21, targeting transaction finality of around 150 milliseconds. #Anza is also developing Rotor and researching post-quantum security through #Quantumglow. 🔗 Full story in comments
Open source - UN
UnchainedArticle ·
Solana Activates Alpenglow on Mainnet, Swapping Out TowerBFT for a Faster Consensus Engine Solana moved its mainnet onto the Alpenglow consensus protocol on Wednesday, retiring TowerBFT , the voting system the network had used since 2020. “Alpenglow is now live on Solana mainnet,” the official Solana account posted at 13:59 UTC. Anza, the developer that built the protocol, had declared it live five minutes earlier. The chain itself records the switch. Unchained’s queries of Solana’s public mainnet RPC show the final TowerBFT-era block, slot 459,652,999 , stamped at about 13:54:00 UTC , and the network’s Alpenglow genesis certificate points to that block. Eight slots then passed with no block before slot 459,653,008 arrived at 13:54:03 UTC. Block heights continued in sequence, with no sign of a rollback. That timing beat Anza’s own estimates. The team first set the switch for about 14:50 UTC, the date Unchained reported on Oct. 14 , and, according to Solana Compass, later pulled its projection forward to around 14:00 UTC. Get Unchained’s crypto news in your inbox with the free Unchained Daily newsletter . The 150 Millisecond Claim Both announcements put a number on the change. Anza wrote that finality was “reduced from 12.8 seconds to 150 milliseconds,” and the Solana account said the same. The 12.8-second figure reflects Solana’s earlier 400 millisecond slots, and the Solana Foundation says slot times have since been cut to 200 milliseconds. Galaxy, which runs Solana validators, wrote in a pre-launch explainer that finality had come down to roughly 6 seconds under the shorter slots. What Changes for Validators Under Alpenglow, validators no longer submit votes as transactions. Votes now travel between nodes as BLS-signed messages that are aggregated into certificates , freeing blockspace for users. A block can be finalized in one round if 80% of stake votes for it, or in two rounds at 60%. The design is meant to keep working with up to 20% of stake acting maliciously and another 20% offline. In place of per-vote fees, each voting validator now pays a flat 0.8 SOL per epoch . Galaxy has noted that vote transactions made up roughly three quarters of Solana’s traffic, and the Solana Foundation expects reported transaction counts and TPS to drop sharply . Wednesday’s switch covers Votor, the voting half of the design. Rotor, which would replace Turbine’s block propagation, is slated for a later phase with no date set. Related Listen: How Mike Dudas Ranks ETH, SOL, and Hyperliquid in a Down Market The post Solana Activates Alpenglow on Mainnet, Swapping Out TowerBFT for a Faster Consensus Engine appeared first on Unchained .
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