Chain reorg

A chain reorganization (reorg) is the event where a node abandons its current chain tip in favour of a competing branch with more accumulated work or weight, reverting the blocks that were replaced.

Because block producers can find blocks near-simultaneously, the tip is temporarily ambiguous until one branch wins. When a node adopts the heavier branch, transactions from the discarded blocks return to pending and may reconfirm at a different height, or not at all. Applications guard against this by waiting for a confirmation depth before treating a transfer as final. Historical queries against an archive node reflect the canonical chain after reorgs settle, so decoded data stays consistent.