Crypto glossary
Fee market
A fee market is the mechanism by which users bid for scarce blockspace, setting transaction fees through competition or protocol rules such as EIP-1559.
When more transactions want into a block than it can hold, someone has to decide who goes first. On Bitcoin the answer is a simple auction: users pick a fee rate, miners sort the mempool by satoshis per virtual byte and fill blocks from the top. Wallets estimate the rate needed to confirm within a target time.
Ethereum changed its fee market with EIP-1559 in 2021. Each block has a protocol-set base fee that rises when blocks are more than half full and falls when they are emptier, and that base fee is burned. Users add a priority tip for validators. The design made fees more predictable and turned high usage into a reduction of ETH supply. Rollups and newer chains experiment with separate fee markets for computation, storage and data, such as Ethereum's blob fees.
Fee markets reveal real demand but can price out small users during spikes. Simple auctions encourage overpaying, and MEV adds private side channels where searchers pay builders directly. Long-term, chains whose block subsidy shrinks rely on a healthy fee market for their security.
Example
When an NFT mint starts, the Ethereum base fee climbs block after block as each one is full; when demand fades, it falls back by up to 12.5% per block.