This comprehensive guide explores blockchain scalability through Layer 1 and Layer 2 solutions, addressing the fundamental blockchain trilemma of security, decentralization, and scalability. Layer 1 improvements—including consensus upgrades, sharding, and block optimization—enhance the base protocol but face implementation challenges. Layer 2 solutions like rollups, state channels, sidechains, and nested blockchains process transactions off-chain, offering faster speeds and lower costs without modifying Layer 1. Each approach presents distinct trade-offs: Layer 1 prioritizes security and decentralization, while Layer 2 emphasizes performance and efficiency. The article compares key differences in mechanisms, solution types, and use cases, then explores emerging Layer 3 protocols for enhanced interoperability and application-specific optimization. Practical insights on trading on Gate, alongside FAQs, help readers determine when to use each layer based on specific needs and priorities.