Anza’s Alpenglow goes live on Solana, cutting finality to 150 milliseconds

Solana’s Alpenglow upgrade, its most significant network overhaul since 2020, will go live on Wednesday. This upgrade reduces the time taken for transactions to become irreversible from six seconds to as little as 150 milliseconds, a significant improvement that is roughly 40 times faster than current speeds. The new system alters how validators, the computers that process and validate transactions, communicate with each other.

Currently, every validator writes its votes directly onto the blockchain, and a payment isn't confirmed until enough votes stack up, typically taking about six seconds. Alpenglow moves this voting process off the chain, replacing it with certificates that can lock in a transaction within one or two rounds. If the 150-millisecond target is achieved on the main network, Solana transactions would settle quicker than the blink of an eye.

This rapid finality brings Solana closer to the speed of card payments or trades on centralized exchanges, which normally take around 13 minutes to reach full finality. However, a noticeable decrease in transaction count might be observed this week as users adjust to the new system. Robin Nordnes, CEO and founder of Raiku, a company building trading infrastructure on Solana, reassured that the reduction in validator votes is not indicative of any issues; rather, most trading activities remain unaffected.

Faster finality is a welcome change, but it was never the main bottleneck. The key factor remains the proximity to where the block is being built. Furthermore, validators will benefit financially from the upgrade. Currently, they burn through approximately 2 SOL per day on vote fees, a cost that doubled after Solana reduced its slot times to about 200 milliseconds.

Alpenglow eliminates these fees in favor of a flat entry charge known as a validator admission ticket, priced at 0.8 SOL per epoch, which lasts about 24 hours. This new fee structure is roughly 60% cheaper. The test network underwent six restarts before the migration to the new system, with one attempt failing and requiring a rollback.

Despite these setbacks, no real money was lost since all tests were conducted on a network designed to handle such disruptions. The switch is scheduled to take effect at the start of epoch 1064 on Wednesday, with the actual change occurring at slot 459,653,000 after a 5,000-slot transition.