MEV (Maximal Extractable Value)
Core ConceptsValue obtainable through transaction inclusion, exclusion, or ordering during block production, beyond ordinary block rewards and transaction fees.
Speak the Language of MEV
Definitions of execution, transaction ordering, private routes, and fees, with documentation links and the limits of each concept.
Front-Running
StrategiesPlacing an execution before an observed target transaction to benefit from its expected effect. Ordering mechanisms vary; a higher gas bid alone does not assure precedence.
Sandwich Attack
StrategiesTrading before and after a target swap to exploit the price movement it causes. The target may receive a worse execution price; slippage limits are only one part of the risk controls.
Flashbots
InfrastructureA research and development organization working on MEV infrastructure and its effects. Its products have distinct interfaces, privacy settings, and submission rules.
Private Relay
InfrastructureA provider-specific submission path outside ordinary public transaction propagation. The recipients may see or simulate the transaction; privacy and inclusion depend on the route.
Bundle
Core ConceptsAn ordered group of transactions submitted under a provider’s rules. Check its ordering, revert, expiration, and atomicity conditions; acknowledgement does not prove inclusion.
Base Fee
Gas & FeesThe protocol-defined per-unit gas fee in Ethereum’s EIP-1559 fee model. It is burned; transaction costs also depend on gas used and the applicable priority fee.
Priority Fee
Gas & FeesThe fee component paid to the block’s fee recipient in Ethereum’s fee model. It can influence selection but does not guarantee position or inclusion.
Searcher
RolesAn operator or program that identifies execution opportunities and submits transactions or bundles. Inputs may include chain state, transactions, and private order flow.
Builder
RolesAn actor that selects and orders transactions to construct an execution payload. Builder behavior, objectives, and available transaction inputs vary.
Mempool
InfrastructureA node’s local collection of received pending transactions. Nodes can have different contents; it is not a single global queue with complete visibility.
Slippage
TradingThe difference between an expected and an executed trade price. A slippage tolerance is a limit used by a particular swap, not a prediction of its execution price.
JIT Liquidity
StrategiesAdding liquidity around a target swap and removing it afterwards. Fee income is subject to inventory, ordering, gas, and adverse-selection risks.
Backrunning
StrategiesExecuting after a target transaction to respond to its resulting state or price changes. Profitability and effects depend on the specific strategy and costs.
Liquidation
StrategiesA lending protocol’s process for resolving a position that no longer meets its collateral requirements. Eligibility, incentives, and execution rules are protocol-specific.
Flashbots Bundle
InfrastructureAn ordered Ethereum transaction group submitted with target conditions. Flashbots documents atomic bundle ordering and optional allowed-revert hashes. Inclusion remains uncertain.
Jito Bundle
InfrastructureSolana transactions submitted to Jito for sequential, atomic processing in one slot. A bundle ID does not prove landing. Uncled-block rebroadcasts may bypass bundle atomicity and revert protection.
MEV-Boost
InfrastructureMiddleware that lets Ethereum validators obtain execution payloads through a marketplace of builders and relays. It is separate from a transaction-submission client.
Block Builder
RolesA builder assembling transactions and bundles into a candidate execution payload. Its bid may be delivered to a proposer through a relay.
Validator
RolesA participant performing consensus duties such as proposing or attesting to blocks. Duties, staking requirements, and rewards depend on the network.
Inclusion Rate
TradingIncluded attempts divided by a defined set of submissions over a stated observation window. Record the chain, route, denominator, retries, and confirmation rule; no fixed FRB rate is asserted.
Revert Protection
InfrastructureProvider-specific handling of transactions that fail simulation or revert. Exceptions, rebroadcast paths, and fee consequences must be checked for the selected route.
Public Mempool
InfrastructurePending transactions propagated between participating nodes. Public propagation exposes details to observers; nodes need not receive identical transactions at identical times.
PBS (Proposer-Builder Separation)
Core ConceptsSeparating selection of the proposer from construction of the execution payload. MEV-Boost is an implementation outside Ethereum’s core protocol; proposed protocol designs may differ.
Atomic Execution
Core ConceptsAll-or-nothing state changes within a defined execution boundary. A transaction and a multi-transaction bundle can have different boundaries and exceptions; verify the system’s rules.
Tip (Solana)
Gas & FeesA payment used in the selected submission mechanism, such as Jito’s bundle auction. It is distinct from the network priority fee and does not ensure inclusion.
Gas War / PGA
TradingCompetition through increasingly high transaction bids for ordering or inclusion. Private routes change the bidding mechanism but do not eliminate competition or ensure cheaper execution.
Honeypot Token
TradingA token whose contract behavior blocks or restricts selling for some holders. Simulations and risk labels can miss changing conditions; they do not establish safety or future sellability.
Anvil Fork
InfrastructureA Foundry local development node using state from an upstream network for testing. The chosen block and configuration constrain what a simulation can establish.
WSS (WebSocket)
InfrastructureWebSocket over TLS, commonly used for persistent subscriptions. Supported events and delivery depend on the provider; connection timing alone does not measure event completeness or execution speed.
SUAVE
InfrastructureA Flashbots research and development initiative for programmable private execution and MEV applications. Check its current documentation for architecture, availability, and limitations.
MEV-Share
InfrastructureFlashbots interfaces for sharing selected transaction information and connecting private order flow with searchers. Refunds and privacy depend on settings and execution outcomes.
Bundle Refund
Gas & FeesA payment returned under a provider’s eligibility and calculation policy. Amount, timing, and availability vary; a submission does not establish entitlement to a refund.
Non-Custodial
Core ConceptsA model where the service does not hold the user’s assets or signing keys. Review signing, storage, and permissions in the actual application; local key control still requires secure operation.