When will you use this?

Use when your React app must talk to a real backend or show live updates.

• React frontends talk to .NET, Node, or Java APIs — fetch and auth are daily tasks.
• Live chat and stock tickers use WebSockets or SignalR with React state.

Real-world: click to database flow

Architect documents Enroll button journey: React onClick → POST /api/enroll → ASP.NET controller → SQL insert → 201 → Query invalidates cache → UI updates.

Production-style code

/*
  Enroll flow:
  1. EnrollButton (React) → mutation.mutate(courseId)
  2. POST /api/enrollments { courseId }
  3. EnrollmentsController validates JWT + seat capacity
  4. SQL INSERT enrollment row
  5. 201 + enrollment JSON
  6. queryClient.invalidateQueries(['enrollments'])
  7. MyCourses list refetches — student sees new course
*/

What happens in production: Full-stack thinking prevents "frontend bug" that is actually API contract mismatch.

Lesson example (start here)

Copy this smaller example first. Once it works, compare it with the real-world code above.

React (Vite/Next) → HTTPS → ASP.NET Core API
                              → SQL Server / PostgreSQL
                              → Redis cache (optional)
Auth: JWT or cookie session

Line-by-line walkthrough

How it works (big picture)

• Frontend never talks to DB directly.
• API validates auth and business rules.
• Env configs separate dev/staging/prod.

Do this on your computer

1. Draw a simple diagram for your app.
2. Define API DTOs shared or documented.
3. Document env vars for frontend and backend.
4. Read the real-world section and name which part of the app uses this topic.
5. Run the example locally and confirm the same behavior in the browser.
6. Change one value in the example (text, initial state, or URL) and predict what will happen before you save.

Experiments — try changing this

• Change text or labels in the example and save — watch the browser update.
• Break the code on purpose (remove a bracket), read the error message, then fix it.
• Open React DevTools (browser extension) while running Full-stack Enterprise Architecture and inspect component props/state.

Remember

UI → API → database. Auth at API boundary. Environment-based configuration.

Common questions