What Is ‘Transaction Finality’ and How Does It Differ across Various Blockchain Architectures?

Transaction finality is the guarantee that once a transaction is recorded on the blockchain, it cannot be reversed, altered, or canceled. In PoW chains like Bitcoin, finality is probabilistic, meaning it increases with each confirmation but is never 100% certain (only economically infeasible to reverse).

In some PoS systems, finality can be absolute or 'cryptographic,' meaning the network consensus makes a reversal mathematically impossible after a certain point.