Monolithic architecture packages everything into a single deployable unit, ideal for early-stage products and small teams but harder to scale. Distributed systems split applications into independent services that can scale separately, suited for large organizations but introducing network complexity and operational overhead. Serverless abstracts infrastructure entirely with on-demand functions, perfect for unpredictable workloads and MVPs but with cold start latency and execution time limits. The right choice depends on team size, operational complexity tolerance, scaling requirements, and time-to-production needs.