This thesis investigates the critical infrastructure choices facing modern tech startups, framing them within a complex interplay of technological innovation, financial sustainability, and an increasingly fragmented geopolitical landscape. The research begins by deconstructing the strategic dilemma between adopting "fashionable" technologies for competitive advantage and selecting "sustainable" stacks for long-term resilience and lower total cost of ownership. A rigorous economic analysis of core services from AWS, Azure, and GCP is conducted, comparing compute, storage, database, and networking costs to highlight financial trade-offs and the strategic implications of vendor-specific startup programs. The study then examines the implementation of a microservices architecture on Kubernetes, evaluating its advantages in scalability and resource efficiency against its inherent complexity and operational overhead for startups.