Deposits and withdrawals Whenever a transaction happens on the blockchain, &8220;miners&8221; use their computers and computing power to verify the transaction on the next big crypto 2022 blockchain ledger. In exchange for verifying these transactions, they get a miner reward fee paid for by the ones initiating the transaction. This miner reward fee is also known as gas fees. Transaction fees are flexible in nature and can vary based on how busy the blockchain is. The $23.7 million that Bitfinex coughed up could well be the biggest ethereum transaction fee in history. And things could have gone much worse for the exchange, given that crypto transactions are irreversible and not subject to regulation.&; MetaMask will have three options to set a gas fee: low, market and aggressive (more details in FAQ above “How do I set the right gas fee?”) and will preselect the fee we think is relevant to your transaction type. You can change this if you prefer, but we provide the best recommendation. For time-sensitive transactions such as Swaps, we recommend and will pre-select an “aggressive” gas fee.