WHAT ACTUALLY HAPPENS WHEN YOU SUBMIT A TRANSACTION

Summary from the TLDR Crypto newsletter

Ethereum transaction processing moved from validators building their own blocks to specialized block builders dominating the process through MEV-Boost relays that auction optimally-ordered blocks to validators selecting the most profitable bids. Transactions propagate through decentralized mempools where each node maintains local versions and compete on fees rather than arrival time, with wallets signing and broadcasting via RPC nodes like Alchemy before builders bundle transactions to capture MEV opportunities. Confirmation arrives after one 12-second slot when the majority attests the block, while finalization requires 12.8 minutes, providing cryptographic permanence that requires one-third of staked ETH to reverse.