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Comment by drcode | Hacker News Reader

> And then if you like that state, you can then pay to send the working transaction to the mainnet to make that same state occur, in a sure bet.

That often isn't true anymore, see https://ethereum.org/en/developers/docs/mev/

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MEV is something different though? GPs (excellent) point is that anyone can play out the effects of their transaction locally ad infinitum, and chose to transact once they're convinced of its behavior. Of course, this can't account for the response of other actors, but the point stands that Medjedovic (should have) been taking far less risk than implied by that quote.

Another thing to note is that all the quotes from Medjedovic are directly to a journalist (at Bloomberg, the article was there a few days ago), which leads me to think there are intentional omissions towards the journalist. It is new that this level of detail is reported about happenings in the crypto space, from traditionally and previously non-crypto publications. It had usually been confined to "broad market selloff, here's a bunch of hot takes from our gloomy college friends on how it goes to zero!" instead of "specific incident within a crypto community, here's what happened". Medjedovic on the other hand is only seen as taking advantage of situations, such as a journalist that is perhaps merely enthused by the crypto asset economy at a publication that needs someone looking at it, but maybe not well versed in it or having editors that would notice either.

Medjedovic stood to lose all of the ETH he was paying in transaction fees (which could have easily been 3 ETH) if someone decided to frontrun his transaction. If that was most of his ETH, that does sound "significant" to me.

He used some kind of MEV shielding thing. But I'm not sure if it went directly to miners or did something else.

Yeah, typically MEV shielding == sending directly to a mining pool that promises that not frontrun it. It's not a guarantee though, the miner could decide to still frontrun, or a small reorg could occur, and another actor could replace the transaction.

> It's not a guarantee though, the miner could decide to still frontrun

The transaction bundle will fail if the success criteria is not reached (often a certain level of profit), so the worst that happens is that the profit margin falls to that level or the transaction is not included with zero cost to the sender

Is that something the mev apis implement? The Ethereum network would still include the transaction and just have it fail.

Exactly, flashbots and similar implement a gateway for submitting transactions directly to the miners. The transactions are only included if they succeed, because part of the transaction transfers payment to the miner for including it and another part of the transaction guarantees success only if it is profitable enough for the submitter. The transaction bundle is not mined unless it succeeds and thus avoids paying gas for failed attempts.

My point is that this is something the flashbot service does before submitting the transaction. There is nothing technical stopping them from submitting it or frontrunning it (besides destroying their reputation). In addition, when uncles and reorgs occur, the rest of the network sees the transaction, and hence could frontrun it / submit it and have it fail.

> but they wouldn't necessarily know what to look for or change if its a distinct kind of transaction

which means non-trading transactions would look so different that someone playing with higher gas wouldn't know what to replace in the bytecode within the 15 seconds between blocks

and the user also has the choice of sending directly to a miner just like the MEV people do, to skip the mempool

which is looks like he did (but not sure, just noticed his contract mentions MEV)

https://etherscan.io/tx/0x1710f8c91f03d43a51b94fb5db00305cdd...

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