A block template is a structure used by miners to create a new block in a blockchain. It serves as a blueprint, containing all the necessary information needed to build and propose the block to the network. Typically, a block template includes a block header, which contains metadata like the version, previous block hash, timestamp, and difficulty target.

It also lists the transactions that the miner intends to include in the block, along with information about the miner’s total reward for including those transactions and any fees associated with them. Miners customize their block templates based on current network conditions, such as congestion and transaction fees.

By selecting which transactions to include, they aim to maximize their potential rewards. Once a miner successfully creates a valid block using the template and solves the cryptographic puzzle, they broadcast it to the network for validation and inclusion in the blockchain. Thus, the block template plays a crucial role in the efficient functioning of mining and the overall integrity of the blockchain.