FCFS Policy

Definition ∞ FCFS Policy, or First-Come, First-Served Policy, is a rule where requests or transactions are processed in the exact order they are received. In blockchain contexts, this often relates to how transactions are ordered within a block by validators or miners. While appearing fair, this policy can be susceptible to front-running, where participants exploit knowledge of pending transactions. It aims for simple and transparent processing order.
Context ∞ The application of an FCFS Policy in blockchain transaction ordering is a subject of debate, particularly regarding its susceptibility to manipulation in high-value decentralized finance operations. Current efforts focus on developing more sophisticated transaction ordering mechanisms that minimize the impact of front-running. These discussions seek to balance transaction efficiency with fairness for all network participants.