Blazor Server vs WebAssembly

Context

Blazor offers two main hosting models for building interactive .NET web applications, and choosing the wrong one can create performance, scalability, or deployment issues. Interviewers use this question to test whether you can reason about runtime architecture and engineering trade-offs.

Core Question

Compare Blazor Server and Blazor WebAssembly. In your answer, explain:

1. Where code executes and how UI updates are handled
2. Pros and cons of each model for latency, scalability, startup time, and security
3. When you would choose one over the other for real product scenarios

Scope Guidance

Go beyond a surface-level definition. A strong answer should cover the request/connection model, dependency on network connectivity, server resource usage, client download size, access to browser capabilities, and how these factors affect architecture decisions in production.