Securing APIs: Protocols and Practices is a comprehensive guide that explores the evolving landscape of API security in the context of modern software development. Covering foundational concepts, authentication and authorization models, emerging protocols, real-world attack vectors, and best practices for secure design, deployment, and monitoring, this book equips developers, architects, and security professionals with the tools and insights needed to protect APIs across complex environments. With a forward-looking perspective on trends like Zero Trust, DevSecOps, and post-quantum cryptography, it delivers both practical guidance and strategic frameworks for building resilient, secure API ecosystems.