SPAs vs. MPAs: Choosing the Right Frontend Architecture

In frontend System Design, architecture isn’t just about which framework we choose or how we organize our components; it’s about how our entire application is structured, delivered, and interacted with in the browser. It defines how the user experiences our product: whether the page reloads on every click or whether content updates seamlessly without a flicker.

Choosing the right frontend architecture is often the difference between an application that feels fast, fluid, scalable, clunky, inconsistent, and hard to maintain.

In this lesson, we’ll examine the two foundational frontend architectures, MPA and SPA, to understand how they work, when to use them, and how they influence the frontend system.

What is frontend architecture?

Before exploring frontend architecture, we first need to understand its parent terms, i.e., web application architectures and application architectures:

• Application architecture is the high-level blueprint defining any software application’s overall structure and design, whether a web, mobile, or desktop application, including both frontend and backend components. It encloses:

  • How different layers (UI, business logic, data) interact

  • Component organization

  • Design patterns (e.g., MVC, MVP)

  • Communication flows

  • Application architecture styles (monolith vs. microservices) and deployment strategies (blue/green, canary, etc.).

Note: Application architecture is a broad term, for example, deciding to build a large-scale e-commerce platform using microservices and event-driven communication.

• Web application architecture is a subset of application architecture and focuses solely on how a web-based application operates. It defines:

  • How the frontend and backend interact

  • API design (REST vs. GraphQL)

  • Authentication mechanisms

  • Web protocols (HTTP/2, HTTP/3, WebSockets)

  • CDN and caching strategy

Example: For e-commerce, it is like defining a ...