Solana flips the switch: Alpenglow goes live, targeting finality of about 150 milliseconds, the chain's first new consensus since 2020

What CoinDesk called Solana's biggest network overhaul since 2020 is live. Anza's Alpenglow consensus protocol reached mainnet at slot 459,653,000, at approximately 14:00 UTC on Wednesday, October 21, 2026, The Block reported. It replaces TowerBFT, the consensus mechanism Solana has run since its launch in March 2020, and follows the day-before preview Cryptoweek published on October 20.

The headline number is finality. Anza says the time for a transaction to become irreversible drops from about 12.8 seconds to about 150 milliseconds, and the previous two-step confirmation becomes one step, which Anza says matters for exchanges crediting deposits and merchants taking payments, per The Block. CoinDesk described the previous wait as roughly six seconds and cautioned that the 150 millisecond target is unproven on mainnet. CoinDesk put the improvement at about 40 times if the target holds.

Under the hood, validator votes move off-chain and are bundled into certificates that can lock in a transaction in one or two rounds, per CoinDesk. That has a visible side effect: transaction counts will fall this week because votes no longer appear as on-chain transactions. "Most of what got counted before was validators voting, and that's off-chain now," Robin Nordnes, chief executive of Solana trading infrastructure firm Raiku, said in an email to CoinDesk.

Validators also pay differently. Vote fees of about 2 SOL a day give way to a flat validator admission ticket of 0.8 SOL per epoch of roughly 24 hours, per CoinDesk, which still leaves hardware and hosting costs; active validators had fallen to 659 at the end of September, per a Bitwise report cited by CoinDesk.

Testing was not smooth: Anza published the design in May 2025, per The Block, and the test network was wiped and restarted six times, with one network-wide migration rolled back, CoinDesk reported, citing Galaxy Digital. What comes next, with no dates, per The Block: Rotor for block propagation, geographically aware leader rotation and a post-quantum design called Quantumglow.