Crypto Finality: How Blockchain Networks Handle Irreversible Payments

Finality in cryptocurrency transactions refers to when a payment is considered irreversible and can't be reversed. However, the concept of finality varies across different blockchain networks.

On Bitcoin, for example, finality is probabilistic and grows with more confirmations. The right number of confirmations depends on the context: two to three for small retail transactions, six or more for larger value transfers, and more still when counterparty risk is unknown.

Ethereum's finality is different, with a time-to-finality around 16-17 minutes due to its checkpointed consensus model. The Ethereum Consensus team aims to shorten this timeframe to tens of seconds, which would improve bridge safety and L2 payment UX.

Solana's upcoming Alpenglow upgrade targets sub-second finality, down from the current 12.8 second TowerBFT finality and around 400 ms pre-confirmation latency. This change could significantly impact how merchants and exchanges treat payments on Solana.