Miner

Miners are the backbone of proof-of-work networks such as Bitcoin, competing thousands of times per second to be the first to produce a valid hash below the network's current target. This computational race, known as Proof of Work, is what lets a decentralised network agree on transaction history without a central authority.

Individually, a single machine has almost no chance of finding a block, so most miners join a mining pool, combining hashing power with thousands of others and splitting rewards proportionally to the work each contributed. Modern Bitcoin mining is dominated by specialised ASIC hardware built solely for SHA-256 hashing, run in large-scale facilities chosen for cheap electricity, since power costs typically make up the majority of a miner's operating expenses.

Roughly every two weeks, the network automatically adjusts mining difficulty so that blocks keep arriving at a steady pace regardless of how much total hashing power joins or leaves. Miner income comes from two sources: the fixed block subsidy, which halves periodically (Bitcoin's next halving is expected around 2028, cutting the reward to 1.5625 BTC), and the transaction fees attached by users, which grow in importance as the subsidy shrinks toward zero.

Not all cryptocurrencies rely on miners; Ethereum and other proof-of-stake networks replaced mining with validators who lock up capital instead of burning electricity.