SSR, CSR, SSG & Hydration - Interview Questions

1. What is Client-Side Rendering (CSR)?

CSR renders the application in the browser using JavaScript. The server sends an initial HTML shell, and Angular generates the UI after loading.

Browser → Load HTML + JavaScript → Angular → Render UI

2. What is Server-Side Rendering (SSR)?

SSR renders Angular pages on the server and sends generated HTML to the browser. It improves initial content visibility and can improve SEO and perceived loading speed.

Browser → Angular SSR Server → Render HTML → Browser

3. What is Static Site Generation (SSG)?

SSG (Prerendering) generates HTML pages during build time instead of per request. It is suitable for static content such as blogs, documentation, and landing pages.

Build Time → Generate HTML → Deploy → Browser

4. CSR vs SSR — what is the difference?

5. When should you use SSR?

Use SSR for public-facing websites requiring SEO, social sharing previews, and faster initial content visibility. Examples include blogs, e-commerce product pages, and news websites.

6. When should you use CSR?

Use CSR for highly interactive applications where SEO is less important, such as admin dashboards, internal applications, and authenticated portals.

7. What is Angular hydration?

Hydration is the process of making server-rendered HTML interactive by connecting Angular's client-side application to the existing DOM.

SSR HTML → Browser → Angular Hydration → Interactive UI

8. Why is hydration needed?

Hydration allows Angular to reuse server-rendered DOM elements instead of recreating them. It reduces unnecessary DOM operations and helps prevent visual flickering.

9. What is hybrid rendering?

Hybrid rendering combines CSR, SSR, and SSG within the same Angular application. Different routes can use different rendering strategies based on their requirements.

{ path: 'articles', renderMode: RenderMode.Server },
{ path: 'admin/**', renderMode: RenderMode.Client }

10. How does Angular SSR work with ASP.NET Core Web API?

Angular SSR renders pages on an Angular server runtime, which can call ASP.NET Core Web API to retrieve data. The API handles business logic and database access.

Browser
   |
   v
Angular SSR Server
   |
   | HTTP Request
   v
ASP.NET Core Web API
   |
   v
SQL Server

11. Does Angular SSR replace ASP.NET Core Web API?

No. Angular SSR handles HTML rendering, while ASP.NET Core Web API handles business logic, authentication, authorization, and database operations.

Both can work together in the same application architecture.

12. What are the SEO benefits of SSR?

SSR provides HTML containing page content to search engines without requiring client-side JavaScript execution. It improves content discoverability and supports dynamic titles, descriptions, and social metadata.

Important Interview Revision Points

Angular + ASP.NET Core — Practical Rendering Strategy

Interview priority: Focus particularly on questions 1, 2, 3, 4, 5, 7, 8, 9, 10, 11, and 12.

Key interview takeaway: Use SSR for SEO-focused public pages, SSG for mostly static content, and CSR for interactive admin applications. Angular can combine all three while continuing to use ASP.NET Core Web API as its backend.