What is a gas fee in crypto and who pays it
A gas fee is the payment to the network for processing a transaction, paid in the blockchain’s native coin.
Gas is a unit that measures how much computation a transaction requires on Ethereum and EVM-compatible networks. Each operation has a gas cost: a simple ETH transfer uses 21,000 gas, while a token transfer or a smart-contract interaction uses more. The fee is the gas used multiplied by the price per unit of gas.
Since the EIP-1559 upgrade, the price on Ethereum consists of two parts. The base fee is set by the protocol depending on how full recent blocks were, and it is burned. The priority fee (tip) goes to the validator and helps the transaction get included faster. Wallets estimate both automatically, but in busy periods the total can jump sharply.
Fees are always paid in the network’s native coin: ETH on Ethereum, BNB on BNB Smart Chain, SOL on Solana, TON on TON. TRON uses a separate model with energy and bandwidth, and Bitcoin charges fees based on transaction size. This is why a customer holding only USDT cannot send it: they also need a little of the native coin.
For merchants, gas matters twice. First, it is part of what the customer pays, so expensive networks discourage small purchases. Second, it is a cost when moving funds from many incoming addresses or sending payouts. Typical mistakes: setting a gas limit too low (the transaction fails and the fee is still spent), assuming fees are constant, and forgetting to keep native coins on addresses that hold tokens.
Moonvex tops up gas on its addresses itself when sweeping received funds, so merchants do not need to keep ETH or BNB on every incoming address.
How to keep gas costs under control
- offer cheaper networks for small payments
- avoid moving funds during peak network load when possible
- batch or schedule consolidation of incoming funds
- keep the native coin available where outgoing transfers are needed