Definition

Front-Running

Meaning ⎊ Exploiting pending transactions by paying higher fees to execute orders first and manipulate prices for personal gain.
Greeks.liveApril 13, 2026

Front-Running

Front-running in the context of decentralized finance occurs when an entity, such as a validator or a bot, observes a pending transaction in the public mempool and submits their own transaction with a higher gas fee to ensure it is processed first. By doing so, the attacker can manipulate the price of an asset to their advantage before the original transaction is executed.

This is a form of predatory behavior that extracts value from unsuspecting users, often referred to as miner extractable value or maximum extractable value. It exploits the transparency of public blockchains where all transactions are visible before they are finalized.

Traders mitigate this risk by using private transaction relays or adjusting their slippage tolerance. This phenomenon highlights the tension between public blockchain transparency and fair market execution.

It remains a significant challenge for protocol designers seeking to minimize information asymmetry.

Front-Running Vulnerabilities
Front-Running Strategies
Transaction Ordering Manipulation
Maximum Extractable Value
Privacy-Preserving Order Books
Front-Running Attacks
Transaction Ordering
Transaction Prioritization

Glossary

Liquidation Front-Running

Mechanism ⎊ Liquidation front-running describes a predatory trading practice where an entity observes incoming transaction data, such as a large pending liquidation order on a decentralized exchange, and executes a preemptive trade to exploit the impending price movement.

Slippage Exploitation

Action ⎊ Slippage exploitation, within decentralized finance, represents a deliberate strategy to profit from the difference between the expected price of an asset and the price at which a trade executes.

Time Decay

Action ⎊ Time decay, within derivative markets, represents the gradual reduction in the extrinsic value of an option contract as its expiration date approaches.

Front-Running Attack Defense

Algorithm ⎊ Front-running attack defense in decentralized finance centers on mechanisms to mitigate information leakage prior to transaction inclusion.

Front-Running Attack

Action ⎊ Front-running attacks represent a sequence of trades exploiting non-public information regarding pending transactions, typically within a decentralized exchange or order book.

Front-Running Deterrence

Action ⎊ Front-running deterrence encompasses proactive measures designed to prevent or mitigate the exploitation of pending transactions, particularly within decentralized finance (DeFi) ecosystems and options markets.

Back-Running Prevention

Countermeasure ⎊ Back-running prevention in cryptocurrency and derivatives markets focuses on mitigating the exploitation of pending transactions by malicious actors.

Gamma Front-Run

Action ⎊ Gamma front-run, within cryptocurrency derivatives, represents a trading strategy exploiting information asymmetry regarding large option orders.

Front-End Filtering

Control ⎊ Front-end filtering serves as a primary control mechanism implemented at the user interface level to prevent specific actions before they are executed on a trading platform.

Private Transaction Relays

Mechanism ⎊ Private transaction relays operate as off-chain communication channels, enabling users to submit transactions directly to block proposers, bypassing the public mempool.