Technical review: Server-side Composition vs. Client-side Composition

Micro frontend architecture has emerged as a transformative paradigm for building scalable and maintainable web applications by extending microservices principles to the frontend. This technical review explores the fundamental dichotomy between server-side and client-side composition strategies within micro frontend implementations. Server-side composition assembles page fragments before delivery to the browser, while client-side composition delegates this process to JavaScript in the client's browser. The document examines implementation mechanisms for both approaches, including Server-Side Includes (SSI), Edge-Side Includes (ESI), and Backend for Frontend (BFF) patterns for server-side composition, alongside Web Components, Module Federation, and framework-specific solutions for client-side composition. Performance characteristics are thoroughly evaluated, highlighting how server-side composition typically delivers faster initial page loads and improved SEO, while client-side composition excels at subsequent interactions and developer autonomy. The review also addresses development workflows, testing strategies, and deployment considerations that significantly differ between approaches. Through case studies in e-commerce and enterprise dashboards, it demonstrates how each strategy suits different application types. A decision framework is presented to guide architects in selecting appropriate composition approaches based on performance requirements, team structures, and business contexts, with many modern applications benefiting from hybrid implementations that strategically combine both paradigms.