Transaction Fee
Paid to the network for processing a transfer, this charge rises and falls with how busy the chain is.
Every transaction pays a fee to whoever produces the block that includes it — miners under proof-of-work, validators under proof-of-stake. The fee is the price of block space, and block space is scarce. When demand spikes, fees climb, sometimes sharply.
On Bitcoin, fees are quoted in satoshis per byte and depend on a transaction's size. On Ethereum, fees depend on computational work, measured in gas. Pay more and you get included faster; a low-fee transaction can sit in the mempool for hours. During the 2021 NFT boom, a single Ethereum swap sometimes cost more than $100.
Related terms
A unit measuring the computational work an Ethereum operation requires, from a simple transfer to a complex contract call.
Gas FeeThe total cost to run an Ethereum transaction, found by multiplying the gas used by the price per unit.
MempoolThe waiting room where broadcast transactions sit before a miner or validator picks them for a block.
TransactionA signed instruction that moves value or data on a blockchain, recorded permanently once miners or validators confirm it.