Gas Fee

A gas fee is the cost of computation and storage required to process a transaction on a blockchain, paid in the network’s native token. It is typically the amount of work ("gas units") multiplied by a per-unit price that the market sets dynamically: when many users compete for limited block space, the price rises, and during congestion it can spike sharply. Gas is paid to the network’s validators or miners, is owed whether or not a transaction ultimately succeeds (a failed/reverted transaction can still burn gas), and is entirely separate from exchange trading fees and AMM slippage. Fee levels vary enormously across chains and layer-2 networks, which is a major factor in where small trades are economical.

In plain English — A gas fee is what you pay the blockchain network (not an exchange) to include and execute your transaction — a swap, transfer, or smart-contract interaction. It compensates validators/miners and rises when the network is busy, because you are effectively bidding for limited block space. On some chains a complex trade during congestion can cost more than a simple transfer many times over, which matters a lot for small trades.

During a busy period an Ethereum swap costs $40 in gas. If you are swapping $100, the fee is 40% of your trade — but the same $40 is trivial on a $50,000 swap. On a low-fee chain the same action might cost a few cents.