Miner

A miner is a participant in a proof-of-work blockchain who uses computing hardware to compete for the right to add the next block of transactions, earning newly issued coins and transaction fees as a reward. Miners repeatedly run block data through a hash function, tweaking an input value until the output meets the network's difficulty target — a brute-force lottery in which more computing power buys more tickets.

Mining serves two purposes at once: it orders transactions into an agreed history, and it makes rewriting that history expensive, because an attacker would have to redo the accumulated work. For example, a Bitcoin mining operation might run warehouses of specialized ASIC machines, and when one of its machines finds a valid block it collects the block subsidy plus the fees of the transactions it included. Most individual miners join mining pools, combining their power and sharing rewards in proportion to contributed work, which smooths out the lottery-like income.

A common misconception is that miners solve useful or complex math problems; the puzzles are deliberately meaningless guesswork whose only function is to prove that energy was spent. Over time, mining has industrialized: what began on hobbyist laptops moved to GPUs and then to purpose-built ASICs concentrated where electricity is cheap. On proof-of-stake networks such as post-2022 Ethereum there are no miners at all — block production is done by validators who stake coins instead of burning energy.