What Is the Concept of “Finality” in Blockchain Transactions?

Finality refers to the guarantee that once a transaction is recorded on the blockchain, it cannot be reversed, altered, or removed. In PoW chains like Bitcoin, finality is probabilistic, meaning it increases with each subsequent block confirmation, typically reaching near-certainty after six confirmations.

In many modern PoS systems, finality is deterministic, meaning once a block is attested to by a supermajority of validators, the transaction is immediately considered irreversible by the protocol itself.