Evaluating Layer 2 Blockchain Scalability through a Comparative Study of Rollups and State Channels

Blockchain scalability remains a major barrier to the adoption of decentralized applications. This paper presents a literature-based comparative analysis of Layer 2 scalability mechanisms, focusing on Optimistic Rollups, Zero-Knowledge Rollups, and State Channels. Drawing on twenty-nine peer-reviewed studies, the work examines architectural design, throughput, latency, cost efficiency, security assumptions, and data-availability models. The analysis indicates that rollup-based solutions significantly improve transaction throughput while preserving Layer 1 security, whereas state channels offer near-instant finality for bilateral interactions but face liquidity and routing constraints.