This article examines the complexities and challenges of implementing federated identity management across multi-cloud microservices architectures. It provides a comprehensive analysis of foundational protocols, including SAML, OAuth 2.0, and OpenID Connect, exploring their roles in enabling seamless authentication and authorization across heterogeneous cloud environments. The article addresses critical aspects of cross-cloud authentication patterns, token translation mechanisms, and interoperability considerations that organizations face when operating in AWS, Azure, GCP, and other cloud ecosystems simultaneously. Particular attention is given to architectural best practices that balance security requirements with operational efficiency, including identity provider placement strategies and service mesh integration approaches. The article also evaluates emerging security paradigms, such as zero-trust models in the context of federated identity, offering insights into risk mitigation strategies and future directions. This article contributes to both theoretical understanding and practical implementation of secure identity management solutions in increasingly distributed and complex enterprise architectures.
Keywords: Authentication, federated identity, microservices, multi-cloud, token translation
