# bestTip() The source’s current best tip — the highest validated block the source knows. ``` func bestTip() async throws -> BlockTip ``` ## Return Value A [`BlockTip`](/documentation/BitcoinKernel/BlockTip) describing the remote best block. The returned tip’s [`timestamp`](/documentation/BitcoinKernel/BlockTip/timestamp) may be `nil` depending on what the source can cheaply provide. ## Discussion Called repeatedly by the sync engine: once at the start of a sync run (to determine the target), and again each time the local chainstate reaches the remote tip (to catch source-side growth or reorgs). > Throws: ``doc://BitcoinKernel/documentation/BitcoinKernel/BlockSourceError`` on transport or parse failures.