Someone Just Paid a $9,000 Fee for a $120 DeFi Transaction

A Reddit user said they accidentally paid a fee 80 times the transaction value while executing a swap on Uniswap.

AccessTimeIconNov 5, 2020 at 12:09 p.m. UTC
Updated Sep 14, 2021 at 10:27 a.m. UTC

A crypto market participant has accidentally paid a fee 80 times the transaction value while executing a swap on the DeFi liquidity protocol Uniswap.

  • About 14 hours ago, the address "0xe6e2e0cf5d2686d73abd7d3ba24f46ad5eb31819" – claimed by Reddit user "ProudBitcoiner" – swapped 0.2955 wrapped ether (WETH) for 531 chi gastoken (CHI) (worth $120) on Uniswap and paid 23.5172 ETH ($9,430 at time of writing) in transaction fees.
  • Mining pool Ethermine processed the transaction and collected the windfall fee, which was way higher than the current average of 0.0022 ETH ($1.07).
  • Often users manually offer a higher-than-average fee in a bid to get their transactions processed quickly. As such, the system is prone to human errors such as typing mistakes.
  • In this instance, ProudBitcoiner said in a Reddit post that they had mistakenly quoted 200,000 in the "Gas Price" input field, instead of the "Gas Limit" field, and ended up paying far above the current 31 gwei gas price.
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  • Gas refers to the internal pricing unit for running transactions on Ethereum and is denoted in gwei. One gwei is equal to a billionth of an ether.
  • The gas limit is the maximum amount of gas provided for a transaction.
  • According to the Reddit post, the user has contacted Ethermine for help over the error.
  • Further highlighting the care needed when manually setting fee rates, in June an unknown wallet holder paid around $5.2 million in fees for two ether transactions.


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