The largest consensus upgrade since Solana's launch in 2020, delivering sub-second, finality.
San Francisco, October 21 /PRNewswire/ — Anza, the leading core engineering team behind Solana, today announced that Alpenglow—Solana’s new consensus protocol that reduces finality to sub-second levels—is now live on Solana mainnet-beta. As Solana powers the internet’s capital markets and increasingly serves as infrastructure for financial applications, Alpenglow delivers the settlement speed required by traditional finance. Transactions are now irreversible in approximately 150 milliseconds, down from 12.8 seconds.
At slot 459,653,000 on Wednesday, October 21, at approximately 14:00 UTC, Solana validators retired TowerBFT—the consensus protocol the network has used since its mainnet launch in March 2020. This migration was completed on Solana’s live production network.
This change targets finality—the point at which a transaction can no longer be reversed. Exchanges, banks, and merchants wait for this point before considering assets as transferred. Throughout most of Solana’s history, finality took approximately 12.8 seconds, while conditional confirmation could be provided within seconds. Alpenglow is designed to compress the previous two-step process into a single step, taking about 150 milliseconds—roughly the duration of a blink. Reducing finality from several seconds to under one second enables faster responses for payment and transaction applications. For merchants accepting payments or exchanges processing deposits, this means an improved user experience.
“This is the largest and most ambitious blockchain upgrade since ‘The Merge,’ and Anza has moved it from whitepaper to mainnet operation in under 18 months,” said Brennan Watt, CEO of Anza. “This aggressive timeline was made possible by the capabilities of our development team and the numerous ecosystem teams and validator operators who helped harden the protocol over the past several months.”
This engineering achievement is not only about speed. Validators replaced the consensus system of the running blockchain core while preserving the existing ledger and continuing forward. Independent operators coordinated a shared transition point from the old protocol, TowerBFT, to Alpenglow, while maintaining network availability.
Before launching on mainnet, Alpenglow underwent public testing, including red team and penetration testing, repeated migration drills, and security competitions. It was subsequently deployed on Solana’s testnet and devnet. Anza developed the protocol and implemented it in Agave, the validator software they maintain; independent validator operators adopted and activated this upgrade.
The Solana blockchain has no single operator. Anza is one of several independent teams developing software for the network. Its research team, led by Professor Roger Wattenhofer from ETH Zurich and including Quentin Kniep and Kobi Sliwinski, released the Alpenglow design in May 2025.
Looking ahead, more improvements related to Alpenglow are planned. Rotor will transform how block data propagates across the network. Geographically aware leader rotation helps reduce latency during leader handoffs. Quantumglow upgrades Alpenglow for post-quantum security—an Anza research design that replaces Alpenglow’s elliptic curve cryptography with hash-based signatures while maintaining the same finality speed. These enhancements are scheduled for future releases, though no specific dates have been set. For current status and technical details, visit anza.xyz/alpenglow.
About Anza
Anza provides engineering support for Solana, delivering software that pushes the boundaries of blockchain performance and scalability. Founded by core engineers from Solana Labs, Anza is responsible for building and maintaining the software that runs validators, researching next-generation protocols, and collaborating with the ecosystem to deploy upgrades on live networks. Learn more at www.anza.xyz.
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