What Is Finality in Solana?
Finality is the guarantee that a confirmed transaction will never be reversed. Once a transaction reaches finality, it is permanently part of the blockchain’s canonical history.
Finality on Solana
Under Tower BFT (the current consensus mechanism), finality occurs when a slot becomes the root — meaning 31+ validators have built on top of it. This takes approximately 12-15 seconds after the transaction is first processed.
Finality vs confirmation
| Stage | Time | Guarantee |
|---|---|---|
| Processed | ~0.5s | Node saw it, may be in a fork |
| Confirmed (optimistic) | ~0.5-2s | Supermajority voted, very unlikely to revert |
| Finalized | ~12-15s | Irreversible, part of the canonical chain |
Most applications treat confirmed as “good enough” because confirmed transactions are reverted extremely rarely (it would require 1/3+ of stake to act maliciously).
Alpenglow and faster finality
The Alpenglow upgrade aims to bring finality down to sub-second using a threshold signature scheme (Roast). When active, finalized commitment will resolve much faster.
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