Web Rendering Techniques
Understanding SSG, SSR, ISR, and CSR
Modern web applications offer multiple rendering strategies, each with unique trade-offs. Choosing the right one can dramatically affect performance, SEO, scalability, and developer experience. Let’s break them down from a practical perspective.
Static Site Generation (SSG)
SSG pre-renders pages at build time, producing static HTML.
Pros:
- Extremely fast to serve and easy to cache via CDN.
- SEO-friendly out-of-the-box.
- Low server load — ideal for high-traffic static sites.
Cons:
- Build time increases with the number of pages.
- Updates require rebuilds unless paired with ISR.
Use cases:
Marketing sites, documentation, blogs with infrequent updates, landing pages.
Server-Side Rendering (SSR)
SSR generates HTML on each request.
Pros:
- Fresh content for every request.
- Full SEO benefits for dynamic content.
- Works well with user-specific or personalized content.
Cons:
- Slower initial response than static pages.
- Higher server load, requires robust infrastructure.
- Caching strategies (e.g., Edge Caching) are often needed to scale.
Use cases:
Dashboards, e-commerce product pages, authenticated content with dynamic data.
Incremental Static Regeneration (ISR)
ISR is a hybrid approach: pages are statically generated, but can be updated in the background at a defined interval.
Pros:
- Combines the performance of SSG with near real-time freshness.
- Reduces rebuild time compared to full SSG.
- CDN caching still works efficiently.
Cons:
- Revalidation adds slight complexity in configuration.
- Not suitable for fully personalized content per request.
Use cases:
Blogs, product catalogs, news sites, marketing sites needing frequent updates without full rebuilds.
Client-Side Rendering (CSR)
CSR delegates HTML rendering to the browser using JavaScript.