Solana's Alpenglow upgrade goes live on mainnet with 150ms finality target

Alpenglow goes live on Solana mainnet

Solana's first major consensus upgrade, called Alpenglow, went live on mainnet at around 1:54 pm UTC on Wednesday. The launch was recorded on the Solana Foundation's Alpenglow dashboard.

Finality is the point at which a transaction is considered settled and cannot be reversed. Solana's foundation said in July that Alpenglow aims to cut finality time by 99%, from about 12.8 seconds to roughly 150 milliseconds.

Key numbers from the upgrade

• Upgrade activation time: about 1:54 pm UTC on Wednesday.


• Target finality: roughly 150 milliseconds, down from about 12.8 seconds — a stated 99% reduction.


• Mainnet finality at press time: 6.6 seconds, with throughput of 4,721 transactions per second, per the Alpenglow dashboard.


• August slot time reduction: the first such change since genesis, part of a plan to halve slot times to 200 milliseconds.


• Fourth stage of the slot reduction plan was completed in October.

How Votor and Rotor change the network

Alpenglow replaces Solana's existing consensus model, TowerBFT. Its first phase, Votor, swaps out the current voting and finalization mechanism for direct validator voting and a certificate-based system. Validators are the computers that help confirm transactions on the network.

A later phase will add Rotor, a new block data-distribution protocol intended to replace Turbine.

The foundation has said the faster finality target could mean quicker payments, faster trade settlements and more responsive applications.

Anza researchers call it the biggest core protocol change

Anza researchers described Alpenglow as the "biggest change to Solana's core protocol" since genesis in a May blog post.

In that post, published May 19, researchers Quentin Kniep, Kobi Sliwinski and Roger Wattenhofer wrote that at 150-millisecond latency, "Solana can compete with Web2 infrastructure in terms of responsiveness, potentially making blockchain technology viable for entirely new categories of applications."

Builders turn to Agave 4.5 next

After Alpenglow, Solana validators are expected to keep working on Agave 4.5. That upgrade proposes raising the number of accounts supported by a versioned transaction from 64 to 96. According to the Solana Foundation, the increase could lead to better swap routes and execution prices. The upgrade is in development and planned for December 2026.

SOL price moved before the launch

The Solana (SOL) token rose nearly 3% in the 24 hours before the upgrade, according to CoinMarketCap. That gain reversed part of the token's 42% decline over the past year.

What is confirmed

Alpenglow activated on mainnet at about 1:54 pm UTC on Wednesday, per the Solana Foundation dashboard. Alpenglow is Solana's first major consensus upgrade and replaces TowerBFT. Votor is its first phase, with Rotor planned later. Anza researchers published the May 19 blog post and its quoted assessment. Agave 4.5 is in development with a planned December 2026 release.

What is still unclear

The 150-millisecond figure is the foundation's stated target, not a measured mainnet result. At press time the dashboard showed 6.6-second finality. Cointelegraph said it had approached the Solana Foundation for comment on Alpenglow's finality measurements in testnet environments and its expected real-world performance, and no response was reported in the source material.

Why it matters

Finality speed affects how quickly a transaction can be treated as settled. Faster finality could make payments, trade settlements and applications on Solana more responsive, according to the foundation and Anza's stated expectations.

Sources

• Cointelegraph