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# tip

The local chainstate’s best block at the moment this [`BlockchainSync.Update`](/documentation/BitcoinKernel/BlockchainSync/Update)
was emitted.

```
let tip: BlockTip
```

## Discussion

Advances monotonically within a single sync run: every
[`BlockchainSync.Update.State.syncing`](/documentation/BitcoinKernel/BlockchainSync/Update/State-swift.enum/syncing) emission has `tip.height` strictly
greater than the previous one’s. During [`BlockchainSync.Update.State.preparing`](/documentation/BitcoinKernel/BlockchainSync/Update/State-swift.enum/preparing)
and terminal states, `tip` reflects whatever the chainstate read
at that moment — including height 0 if the chainstate is fresh.