GraphQL and REST are two distinct API design paradigms that cater to different needs and use cases. REST, built on a resource-centric model using HTTP verbs, is simple, familiar, and scalable, with strengths in simplicity, scalability, broad support, and flexibility. However, it has limitations such as over-fetching, under-fetching, endpoint proliferation, versioning overhead, and performance issues in complex scenarios. GraphQL, a query language for APIs, offers precise data fetching, single-endpoint simplicity, flexibility and evolution, ecosystem and tooling, but also comes with challenges like learning curves, caching complexity, server-side overhead, and less universal support. Understanding the architectural differences, advantages, trade-offs, and security considerations between REST and GraphQL will enable developers to choose the right API architecture for their specific needs, whether it's simplicity, scalability, or flexibility.