Blockchain: Solana tests Alpenglow aiming for finality in 150 milliseconds

By: journalducoin.com|09/27/2026 16:00:00

Solana aims to make its transactions final in the blink of an eye. The network has launched tests of its Alpenglow update, a redesign of its consensus that could reduce transaction finality from 12.8 seconds to 150 milliseconds.

Exchange platforms, cross-chain bridges, and merchants could then consider a payment irreversible almost the instant it is sent.

Key Points

  • Solana has launched tests of Alpenglow, the redesign of its consensus that could reduce finality from 12.8 seconds to 150 milliseconds.
  • Designed by Anza, Alpenglow replaces TowerBFT and Proof of History with two components: Votor for voting, and Rotor for block dissemination.
  • Exchange platforms, bridges, and merchants could consider a payment irreversible almost instantly, much faster than with a credit card.
  • Supported by over 98% of validators, the protocol tolerates 20% malicious stake and an additional 20% offline.

What Alpenglow Changes in Solana's Blockchain Consensus

Finality refers to the moment when a transaction can no longer be canceled or reorganized by the network. It is then considered definitive and irreversible. For Solana, this occurs on the TowerBFT side, its proprietary consensus system. Under the hood, TowerBFT relies on a method called Proof of History (PoH), which divides time into slots of 400 milliseconds. Thus, a block only becomes final after 32 slots of successive confirmations, currently taking 12.8 seconds.

Alpenglow disrupts the internal workings of Solana. Indeed, it replaces both TowerBFT and Proof of History at the core of the consensus. The protocol was unveiled just over a year ago by Anza, the company spun off from Solana Labs that develops the Agave validator software. Anza's researchers designed it with the support of Roger Wattenhofer, head of the distributed computing group at the Swiss Federal Institute of Technology Zurich.

Alpenglow relies on two components. On one hand, Votor orchestrates the voting of validators, weighted by their stake (the SOL locked to secure the network). A fast track finalizes a block in a single round if validators representing 80% of the stake approve it, while a slow track takes two rounds if they only represent 60%. Both tracks run in parallel, and the first to succeed sets the finality.

On the other hand, Rotor succeeds Turbine for block dissemination. The producer of each block entrusts its fragments to a single layer of relay nodes selected based on their stake, whereas Turbine had them transit through a multi-tier tree.

The majority of transactions recorded on Solana today are validator votes. The new protocol will circulate them off-chain, grouped into certificates that serve as compact proofs of the vote. The space freed up in the blocks will return to user transactions.

Thus, these two developments will allow nodes to agree more quickly on the finality of a transaction and also enable them to disseminate it more efficiently across the network.

A finality in 150 milliseconds: what crypto gains

With this proposal, Anza hopes to achieve a median finality of 150 milliseconds. Measurements from simulations calibrated on the actual stake distribution show that some blocks have even been finalized faster, in 100 milliseconds.

For now, the update is still relatively experimental. Indeed, it will be deployed this week on Solana's testnet. This will allow Anza's developers to test their system in a real-world situation and correct any potential failures encountered.

With this update, Solana aims to become one of the fastest blockchains. For comparison, on Ethereum, one must wait for two epochs of 32 slots of 12 seconds each, which theoretically amounts to 12.8 minutes before a block becomes irreversible. On Bitcoin, the common rule of six confirmations represents about an hour, and finality remains probabilistic. Indeed, each added block makes a cancellation less likely, but never entirely excludes it.

Such a short finality would allow an exchange platform to credit a deposit almost at the moment the user validates the sending. Bridges would also benefit, as every second of waiting immobilizes funds and leaves a window for a potential chain reorganization.

For a merchant, the finality delay matters more than the throughput in transactions per second, which blockchains often use as a commercial argument. The blockchain has already made its entry into payments. Indeed, as early as 2023, Visa expanded its USDC settlement system to Solana, and Western Union has chosen the network to issue its stablecoin USDPT. A payment by credit card is authorized in one to two seconds, but the settlement between banks then takes one to two business days, and the customer can dispute the transaction for several months. A transfer in stablecoin on Solana would become definitive even before the terminal displays "payment accepted".

A Security Compromise Approved by Over 98%

Alpenglow claims a "20+20" resilience. This means that the network remains capable of finalizing blocks with 20% of the stake in the hands of malicious actors and an additional 20% offline. Classic BFT protocols tolerate just under a third of malicious participants. Anza thus lowers this threshold in exchange for better resistance to server failures, which are much more common than coordinated attacks.

The protocol modifications are described in Solana Improvement Documents (SIMD), and some, like Alpenglow, go through a vote by validators. The SIMD-0326 proposal was overwhelmingly approved last September with over 98% of votes in favor. However, it is worth noting that the vote recorded participation of about half of the total stake mobilized on the network.

The testing phase that is now opening must verify that the figures obtained in simulation hold outside the laboratory. The new protocol must then be integrated into Agave as well as Firedancer, the validator software from Jump Crypto, before any activation on the mainnet.

Solana will then finalize its blocks without Proof of History, the invention that co-founder Anatoly Yakovenko placed at the heart of the network's original whitepaper in 2017.

-- Price

--
--
--

This content is provided for general informational purposes only and doesn't constitute financial, investment, legal, or tax advice. Any events, rewards, online promotions, or related information mentioned herein should not be considered a recommendation, solicitation, or invitation to purchase, sell, trade, or otherwise deal in any crypto assets. Crypto assets are highly volatile and may result in loss. The availability of WEEX services, products, and related events may vary by region. You are responsible for ensuring that your participation is in accordance with applicable local laws and regulations.

You may also like

iconiconiconiconiconiconiconiconicon
Customer Support:@weikecs
Business Cooperation:@weikecs
Quant Trading & MM:bd@weex.com
VIP Program:support@weex.com