blocknumber

blockNumber is a term used in blockchain systems to refer to the height or position of a block within a chain. It represents the number of blocks that precede the block plus one, effectively counting blocks from the genesis block. In most networks, the genesis block has the number 0, and subsequent blocks increase this value by one for each new block added to the canonical chain. The blockNumber is a simple, incremental counter that helps users and software identify and compare blocks by order rather than by hash alone.

In practice, blockNumber is used to query, reference, and verify blocks. It appears in block headers as a field indicating the block’s height and is commonly exposed by blockchain nodes via APIs. For example, JSON-RPC or similar interfaces may allow callers to request a specific block by number or to query the most recent block using special identifiers such as latest or pending. The block’s number can be used to calculate confirmations, which depend on the difference between the latest known block number and the target block number.

blockNumber should not be confused with a block’s hash. The hash uniquely identifies a block’s contents, while the number identifies its position in the chain. In many implementations, the number is returned as a hexadecimal string in API responses, though it represents a simple integer. The concept applies across most blockchains, with minor variations in notation and interpretation depending on the protocol.