Gas (network fee)
Fee paid to validators for executing a transaction on a blockchain.
Gas: blockchain fuel. Each operation costs gas units × price (gwei on ETH, sat/byte on BTC). Rises with congestion. L2s reduce 10-100x. Solana flat ~$0.001.
In plain words
Every blockchain transaction costs a fee for the people running the network. On Ethereum it's called gas and rises when the network is congested. A simple transfer is a few dollars, a complex swap tens. L2s (Arbitrum, Base) and Solana cost cents.
Example
ETH transfer: 21k gas × 20 gwei = $1.5. Uniswap swap: 150k × 20 = $10. NFT mint hot: 200+ gwei = swap $100+. Arbitrum: $0.30. Solana: $0.001.
Also known as: gas fee, opłata gazowa, gwei, network fee