This work introduces a framework for evaluating onchain order flow auctions
(OFAs), emphasizing the metric of price improvement. Utilizing a set of
open-source tools, our methodology systematically attributes price improvements
to specific modifiable inputs of the system such as routing efficiency, gas
optimization, and priority fee settings. When applied to leading Ethereum-based
trading interfaces such as 1Inch and Uniswap, the results reveal that
auction-enhanced interfaces can provide statistically significant improvements
in trading outcomes, averaging 4-5 basis points in our sample. We further
identify the sources of such price improvements to be added liquidity for large
swaps. This research lays a foundation for future innovations in blockchain
based trading platforms.