Building for scale in today's tech ecosystem involves focusing on four critical elements: elasticity, availability, observability, and speed. Elasticity refers to the ability of infrastructure to adjust resources in real-time to meet fluctuating demands, ensuring systems can handle spiky traffic without delays. Availability ensures systems remain operational and accessible, employing redundancy and failover mechanisms to minimize service interruptions. Observability provides insight into a system's internal state, enabling proactive maintenance and optimization of performance and reliability. Speed emphasizes the need for lightning-fast user experiences, achieved through efficient code, optimized network performance, and caching strategies. By incorporating these elements with the help of serverless technology, companies can successfully scale their operations while maintaining performance and reliability.