Designing Developer Self-Service: Portals, Golden Paths, and Guardrails explores how modern organizations can empower engineers through intelligent, secure, and user-centered platform design. It examines the evolution of internal developer platforms from simple automation layers to holistic ecosystems that balance autonomy with governance. Through deep analysis of patterns, architectures, and real-world case studies, the book reveals how to create self-service experiences that scale across teams, technologies, and cultures. Blending technical rigor with product thinking, it shows how portals, golden paths, and guardrails transform software delivery into a seamless, reliable, and human-centered experience that accelerates innovation while maintaining trust, compliance, and sustainability.