Transaction Fee Market
The competitive process by which users bid, through their offered fee, for limited block space, with higher bids generally getting priority inclusion.
A transaction fee market describes the competitive dynamic through which users bid for a blockchain's limited block space using their offered transaction fee, with block producers generally prioritizing including whichever pending transactions offer the most attractive combination of fee and the resources (such as gas) they require. When many users want to transact at the same time and block space is limited, fees rise as users compete against each other for inclusion in the next available block.
Different blockchains structure their transaction fee market differently — Ethereum's EIP-1559 design separates fees into a base fee (see Kaavon's "Base Fee" glossary definition) that's burned and a priority fee (see Kaavon's "Priority Fee" glossary definition) tip paid directly to the block producer, while other chains use simpler first-price auction models where users directly bid their full offered fee against each other. Understanding a given chain's specific fee market design helps explain practical behavior like fee spikes during high demand, the viability of a priority gas auction (see Kaavon's "Priority Gas Auction (PGA)" glossary definition), and how gas fees respond to changing network congestion.
Examples
- During a period of high network demand, a blockchain's transaction fee market can see fees spike sharply as users compete for the same limited block space.
- Ethereum's EIP-1559 transaction fee market design, separating a burned base fee from a priority fee tip, differs meaningfully from a simpler first-price auction model used by some other chains.