Minibuilder - Flash

Sort incoming bundles by priority_fee or the extractable value minus gas cost.

Use Go or Rust to create an RPC server that accepts eth_sendBundle requests but does not propagate them to the public mempool. flash minibuilder

Establish direct TCP connections to validators' engine_api endpoints. Submit your miniblock as a engine_forkchoiceUpdated call with a payload attribute. Sort incoming bundles by priority_fee or the extractable

A is not a full block builder. Instead, it is a specialized, high-velocity engine designed to construct "miniblocks" or partial block bundles with extreme efficiency. These miniblocks are usually composed of time-sensitive transactions—often MEV strategies like arbitrage or liquidations—that must be executed within a single slot or even a sub-slot timeframe. it is a specialized

As blockchains evolve from toy networks to global settlement layers, the race is no longer about blocks per second. It is about . And the Flash Minibuilder is leading that race.

Enter the . This emerging piece of middleware infrastructure is quietly rewriting the rules of how blocks are built and submitted. While most users are focused on Layer 2 rollups and faster consensus mechanisms, the Flash Minibuilder is optimizing the final, crucial mile of transaction inclusion. What Exactly is a Flash Minibuilder? To understand a Flash Minibuilder, you must first understand the traditional block building pipeline. Typically, a blockchain (like Ethereum) has a mempool where pending user transactions sit. Block builders scan these transactions, select the most profitable ones (usually those paying the highest gas fees), and assemble them into a block. That block is then proposed to the network.