Curriculum·J302 Swap Execution: AMMs, MEV, and DEX Architectures·about 31 min
Execution discipline on-chain
By the end of this lesson you can
- →Run the pre-swap checklist that the preceding four lessons produce
- →Explain why separate wallets do not protect against a repeated configuration error
- →Compute the annual cost of a default setting against the tail it permits
- →Record realized against quoted price so that execution becomes measurable
Junior · enrolled learners
This lesson opens with The same trader, six times in one day.
- What happened
- Following the sandwich attack of 12 March 2025 that turned a 220,764 USDC swap into about $5,271, the researcher known as DeFiac reported that the same trader appeared to have been caught by six comparable attacks within a single day, operating across different wallets. Two of the other wallets lost $138,838 and $128,003. The three losses that were quantified publicly total $482,341. The wallets were separate. The transactions were separate. What was not separate was the configuration each swap was submitted with, which per J302-04 is the field a searcher reads to decide whether a transaction is worth acting on.
- The decision point
- Using different wallets is compartmentalisation, and per S209-03 compartmentalisation only works when a failure inside one cannot reach the others. Here the failure was not in a wallet. It was in a setting that traveled with the operator to every wallet they used, so six compartments produced six independent instances of one error rather than containing it. A compartment that does not isolate the actual failure mode is a filing system.
- Recorded loss
- $482,341
What you will be able to answer
- →Why did separate wallets not help?
- →What is the pre-swap checklist?
- →What shape does execution cost have?
- →What makes execution measurable?
Orientation and Year One are open: anyone can read them without an account. From Year Two onward the lessons are for enrolled learners, because progress through the later years only means anything if it is tracked against a record.
It is free. We do not sell the list and there is nothing to buy at the end of it.
Sources and review
- https://cointelegraph.com/news/crypto-trader-loses-least-215000-stablecoins-from-sandwich-attack
- https://www.cryptotimes.io/2025/03/13/crypto-trader-loses-215k-in-mev-sandwich-attack/
- https://blog.uniswap.org/minimize-slippage-on-swaps
- https://collective.flashbots.net/t/post-mortem-april-3rd-2023-mev-boost-relay-incident-and-related-timing-issue/1540
Confidence medium·Volatility medium·Reviewed 2026-08-06·Owner unassigned
Contested
The six-in-one-day attribution is a researcher's on-chain analysis linking wallets by behavior, not a confirmed account of one person's activity. Marked medium confidence. Three losses were quantified publicly and those are the figures used; the structural point about configuration traveling with the operator does not depend on the linkage being exact.
Per P10 the cost figures in the worked example are illustrative of a trading frequency, not a prediction about any reader's results, and the lesson makes no claim that better execution produces profit.