Angular18 min read

Angular SSR (Server-Side Rendering) Explained Clearly

Understand SSR, why it matters for SEO and performance, and what changes in your code.

Ethan Walker
December 21, 2025
0.0k0

SSR means the server renders HTML first, so the browser receives a ready page. ## Why SSR matters ### 1) SEO Search engines can read server-rendered HTML better than an empty page. ### 2) Faster first paint Users see content earlier. ## CSR vs SSR (simple) ```mermaid flowchart LR A[CSR] --> B[Browser downloads JS] B --> C[JS builds HTML] C --> D[User sees content] E[SSR] --> F[Server builds HTML] F --> G[Browser shows HTML quickly] G --> H[JS hydrates and becomes interactive] ``` ## What "hydration" means Hydration means Angular takes over the already-rendered HTML and adds interactivity (clicks, inputs). ## Biggest SSR gotcha Do not access browser-only APIs directly: - window - document - localStorage Because they do not exist on the server. Better: check platform or use injection tokens. > Next: SSR safe patterns (Platform checks and TransferState).

#Angular#SSR#Advanced