Reorgs.When the chain changes its mind.
Reorgs our collector saw
Every minute the collector re-reads the last ten blocks it stored. A height that now has a different block was reorganised; the depth is how many stored blocks were replaced (“+” when all ten were, so it may have been deeper).
None recorded since this tracker started.
Alternative chains
Branches our node knows that lost to the main chain. Height is the branch’s top block; length is how many blocks it has.
None right now.
Tracking started when this page went live; nothing before that is shown. See also hard forks and the latest blocks.
Questions
What is a reorg in Monero?
Two miners can find a block at the same height. Nodes follow the chain with the most cumulative work, so when the other branch grows longer, the blocks on the losing branch are replaced — a reorganisation. The replaced blocks become orphans (alternative blocks).
How deep can a Monero reorg be?
A one-block reorg happens now and then when two blocks are found close together. Deeper ones are rare and are what a selfish-mining pool or an attacker would cause, which is why this page records the depth of each one we see.
How many confirmations are safe?
Monero wallets lock received funds for 10 blocks, and services usually wait for at least that many. A reorg deeper than the confirmations you wait for could undo a payment, so the depths recorded here are the evidence for that choice.