What is the 'finality threshold' in Avalanche terms?

• A. The required supermajority of validators needed to finalize a decision with high probability.
• B. The maximum number of validators that can be offline.
• C. The time window within which a block must be committed.
• D. The minimum stake required to participate in finality.

Answer: (A)

In Avalanche terms, the finality threshold is the required supermajority of validators that must endorse a decision for it to be considered final with high probability. This means you need a large fraction of the validator set agreeing in order for the system to treat the choice as irreversible within the network’s probabilistic finality model. In practice, Avalanche aims for about two-thirds of the active validators to concur in a poll; with N validators, that corresponds to roughly floor(2N/3) + 1. This threshold protects safety: even if up to one-third are faulty or malicious, they can’t flip the final decision once the threshold is reached. Because finality is probabilistic, it typically requires a few successive polls with the same outcome to achieve near-certain finality, after which the chance of reversing becomes negligible. The finality threshold is distinct from things like how many validators can be offline, a time window to commit, or minimum stake—those touch availability, timing, or participation costs rather than the vote threshold that yields finality.