Topic - Most important Backend topics to revise before interviews

Most important Backend topics to revise before interviews
Most important Backend topics to revise before interviews (save this) :

1. API Design & HTTP Fundamentals

- REST principles, CRUD mapping
- HTTP methods (GET, POST, PUT, DELETE, PATCH)
- Status codes (200, 201, 400, 401, 403, 404, 500)
- Idempotency, headers, query vs params
- Pagination, filtering, versioning

2. Authentication & Authorization

- JWT (access vs refresh tokens)
- Sessions vs s
- OAuth basics (Google login flow)
- Role-based access control (RBAC)
- Password hashing (bcrypt)

3. Databases (VERY IMPORTANT)

- SQL vs NoSQL (when to use what)
- Joins, indexing, normalization
- Transactions & ACID properties
- Query optimization (avoid N+1 queries)
- Schema design & relationships

4. Caching & Performance

- Why caching is used
- Redis basics (key-value, TTL)
- CDN concept
- Cache invalidation strategies
- Reducing DB calls

5. System Design Basics

- How to design scalable systems
- Load balancing (horizontal vs vertical scaling)
- Rate limiting
- CAP theorem basics
- High availability vs consistency

6. Server & Runtime Concepts

- How backend actually works (request → server → DB → response)
- Node.js event loop (callbacks, promises, async/await)
- Blocking vs non-blocking I/O
- Thread vs process basics

7. Error Handling & Logging

- Try/catch, global error handlers
- Logging levels (info, warn, error)
- Debugging production issues
- Monitoring basics

8. Security Fundamentals

- Hashing vs encryption
- SQL Injection, XSS, CSRF
- Rate limiting & brute-force protection
- HTTPS, CORS basics
- Environment variables & secrets

9. Architecture Patterns

- Monolith vs Microservices
MVC pattern
- Service , controllers, routes
- Clean code & separation of concerns

10. Message Queues & Async Processing

- Why queues are needed
- Basics of Kafka / RabbitMQ
- Background jobs (emails, notifications)

11. File Handling & Storage

- Uploading files
- Cloud storage (S3 basics)
- Handling large files efficiently

12. Testing & Deployment

- Unit testing vs integration testing
- API testing (Postman)
- CI/CD basics
- Docker basics (containers)
- Deployment flow (build → test → deploy)

Most candidates prepare works.
Top candidates understand how systems actually work.

That’s the difference between:
“Can build APIs” vs “Can build scalable products.”

Subsection: Learning Section
Section: Student Zone

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