As frontend applications become more complex, choosing the right architecture becomes critical. The structure of your application determines how it loads, scales, and performs. In this part of the Frontend Fundamentals series, we’ll explore what frontend architecture means, why it matters, and break down key architectural patterns like Monolithic vs Micro Frontends and different rendering strategies: CSR, SSR, SSG, and ISR.
What is Frontend Architecture?
Frontend architecture is the design and structure of your frontend codebase and how it interacts with the rest of the system – backend services, APIs, CDNs, and ultimately the browser.
A good architecture:
- Keeps code organized and maintanable
- Supports scalability (more features, more developers)
- Optimizes performance and user experience
- Aligns with the business and technical goals of your product
Monolithic Frontends vs Micro Frontends
A monolithic frontend is a single application where all UI logic is bundled together – often built with one framework (e.g., React, Angular, Vue) and deployed as a single unit. The simplicity of this model is a major strength. Developers can work in a single repo with a unified tech stack, making it easy to share components and styles across the application. There are fewer moving parts, which can speed up initial development and reduce infrastructure complexity.
However, monolithic apps can become unwieldy as they scale. Large teams working in the same codebase can introduce bottlenecks, and deploying even a small change requires rebuilding and shipping the entire app. This approach also limits flexibility – for example, you can’t easily introduce a new framework or tech stack for a single feature without affecting the whole system.
Inspired by microservices, micro frontends split the UI into independent, self-contained apps, each owned by different teams and deployed separately. This approach enables teams to move faster and independently, scaling development across large organizations. It also improves fault isolation — if one part of the UI fails, it doesn’t necessarily bring down the entire application. Plus, micro frontends make gradual upgrades easier, since teams can adopt new technologies incrementally.
On the downside, micro frontends introduce significant architectural complexity. Shared state, routing, and styling across micro apps can be difficult to manage consistently. Performance can suffer if you’re not careful, especially if multiple frameworks are loaded at once. Debugging and local development may also be more involved, requiring tooling to simulate the full app environment.
Rendering Strategies: CSR, SSR, SSG, and ISR
Beyond how the app is structured, how it is rendered also plays a big role in frontend architecture.
Client-Side Rendering (CSR) is the classic SPA model where the browser downloads JavaScript and renders content dynamically. This offers great interactivity and a smooth user experience once the app is loaded, but can suffer from slow initial load times and poor SEO out of the box.
Server-Side Rendering (SSR) renders the initial HTML on the server, sending a fully formed page to the browser. This improves performance and SEO significantly, especially for content-rich or public-facing pages. However, SSR requires a running server and adds complexity to caching and infrastructure.
Static Site Generation (SSG) pre-renders pages at build time, combining the performance of static files with the benefits of server rendering. This is ideal for sites with content that doesn’t change frequently. The tradeoff is longer build times and less flexibility for dynamic content.
Incremental Static Regeneration (ISR), a hybrid approach popularized by frameworks like Next.js, allows static pages to be regenerated on demand. This offers the benefits of SSG while still supporting frequently updated content – though it relies on CDN strategies and framework-specific support.
Real-World Use Cases
To understand how these architectural approaches play out in the real world, let’s look at a few examples.
Many traditional web apps – like early versions of e-commerce sites or CMS platforms – followed a monolithic architecture, where the backend rendered HTML and served it directly to the browser. This worked well for small teams and simpler applications but became harder to scale as user interfaces became more dynamic.
As apps grew more interactive (think dashboards, social platforms, SaaS tools), Client-Side Rendering (CSR) became popular – notably championed by frameworks like React and Angular. Companies like Facebook and Airbnb leaned heavily into CSR for rich interactivity, but they also had to invest heavily in performance optimization because of slower initial load times.
To address SEO and load-time issues, Server-Side Rendering (SSR) made a comeback, especially with tools like Next.js. It’s now commonly used by companies that need fast, indexable pages — like news websites, e-commerce platforms, or content-heavy apps.
Meanwhile, Micro Frontends have become increasingly popular in large-scale organizations with many independent teams – for instance, Spotify, Amazon, and Zalando use this approach to let teams ship independently without stepping on each other’s toes.
Each of these use cases reflects the idea that there’s no one-size-fits-all solution – the right frontend architecture depends on your app’s needs, your team’s size, and your goals around performance, SEO, and scalability.
Coming Up Next: Frontend Frameworks
Now that we’ve covered frontend architecture, the next step is to look at the tools that help implement these strategies. In the next post, we’ll dive into Frontend Frameworks – comparing React, Vue, Angular, and others to understand their strengths, patterns, and best use cases.
