A Block Builder is a tool or entity responsible for constructing new blocks on a blockchain. This process involves compiling a collection of transactions that need to be added to the ledger, ensuring they are valid according to the network’s rules. Block Builders play a crucial role in the transaction validation process.

They gather transactions from a pool, prioritize them based on factors like fees, and package them into a block. Once a block is constructed, it is then proposed to the network for validation and eventual addition to the blockchain.

In some networks, especially those that use proof-of-work or similar consensus mechanisms, Block Builders may also participate in the competitive mining process. Here, they try to solve complex mathematical problems to add their constructed blocks to the chain and earn rewards.

Emerging trends include specialized Block Builders that focus on efficient block construction, supporting scalability and reducing transaction times.