Introduction

MEV, also known as Maximum (or Miner) Extractable Value, is apparent in both Proof-of-Work or Proof-of-Stake blockchains today (e.g., Bitcoin and Ethereum). MEV, in simple terms, can be described as the measure of total value that may be extracted from transaction ordering permissionlessly. With this ability, a miner/validator can extract additional economic gain on top of the fees and revenue generated when building a block. 

The Proposer-builder separation (PBS) divides the block packaging validator into two parts, namely block-builder and block-proposer. The block-builder can specify the order in which transactions are executed on the chain. The block-proposer is responsible for packaging the final block, but cannot see & modify the transactions specified by the block-builder.

PBS is an important mechanism for following reasons: It creates opportunities to prevent transaction censorship at the protocol level. And it prevents hobbyist validators from being out-competed by institutional players that can better optimize the profitability of their block building.

The BEP322 is a PBS implement on BNB Smart Chain. The validator is responsible for finally generating the block. The builder can specify a set of ordered transactions aka bundle, which can ensure that the transactions are finally executed on the chain in the order in the bundle, validator cannot adjust the order and transactions in the bundle.

The Meganode MEV API is a simple and convenient way for users/developers to access the MEV world. Developers do not need to run their own builder or validator nodes. They only need to send ordered transactions through the eth_sendBundle API. It also supports using the eth_queryBundle API to query the execution status of the sent bundle. It provides several key features:

• Privacy. All transactions sent through this API will not be propagated on the P2P network, hence, they won't be detected by any third parties. This effectively prevents transactions from being targeted by sandwich attacks.
• Batch transaction. Multiple transactions can be consolidated into a single 'bundle', which can then be transmitted through just one API call. The sequence of transactions within a block, as well as the order within a bundle, can be assured to maintain impeccable consistency.
• Atomicity. Transactions within a bundle either all get included on the chain, or none at all. There's no such scenario where only a portion of the transactions are included on chain.
• Gas protection. If a single transaction within a bundle fails, the entire bundle is guaranteed not to be packaged onto the blockchain. This mechanism safeguards users from unnecessary gas expenditure.

Developers can get more information about Meganode MEV APis here.

Reference
Introduction about (MEV) Maximal Extractable Value
Introduction about PBS (Proposer-builder separation)
Introduction about BEP322