Since The Merge, the role of organizing transactions into blocks has been outsourced by 90% of validators to a specialized role called Builders. Builders collect transactions from the mempool and from separate endpoints for sending orders outside the mempool. Often, these private orders all compete over finding and extracting value over the same set of public transactions. The name for the role of people who do this are called Searchers. An example, would be many searchers competing to find arbitrage created after someone made a large trade and sent this trade in the mempool (where these searchers can see it).
Searchers compete on extracting value from the same set of transactions in an auction. The Builder hosts this auction, and the Searchers trust the Builder to run it honestly. A dishonest Builder may see Searcher's requests, gain some insights from them (insider trading), and then use that to their advantage (eg. replace the Searcher request with their own and take all the extracted value). There are many other ways that Builders could behave dishonestly. Today we have little-to-no visibility in how this auction is being run.
Meanwhile, these Builders are participating in another auction - the Builder Bid Auction, where the highest paying Builder has their block accepted. A role called a Relay runs this auction, and forwards the highest paying bid to the Validator. Again, this is a situation of trust, the Relay could take the transactions from the builder, and build a new block where they keep profits for themselves. Meanwhile, they could be dishonest about the value to the block when sending it to the Validator. However, many tools have been built around the Relay and Builder relationship to provide visibility, such as https://relayscan.io, https://payload.de/data/, https://mev.to, and https://mevboost.pics.
The Searcher and Builder relationship lacks this caliber of visibility. We wanted to address this problem with primary goals:
We began with a simple API spec that seeks to start accomplishing these goals. We wrote a reference implementation to it on-top of open-source https://github.com/flashbots/builder codebase. We built a front-end dashboard to visualize the data.
Builder Codebase Patch: https://gist.github.com/JVillella/953a8444bcb4faba9e7440d10dfcdcc0 (this is done as a patch, we want to polish this up and make it into a PR upstream to flashbots/builder this week) Dashboard code (PLEASE SEE PR 1): https://github.com/gmbit-co/gmbit.co/pull/1