Block producers run the infrastructure necessary to run the FIO Chain, and play a major role in the governance of the chain. Those holding FIO Tokens choose the block producers through vote. Blocks are produced exactly every 0.5 seconds by a specific block producer designated to produce a block at that time. Blocks are produced in rounds of 126 (6 blocks each times 21 producers). In FIO, block producers can modify system smart contracts with ⅔ + 1 (15 BPs) supermajority.
The block producer API details the transactions available for managing the FIO chain.