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Backend Specialist Interview Path

Master backend engineering interviews with real-world use cases. Each scenario includes key topics, interview questions, and technical concepts you'll encounter at top tech companies.

8
Use Cases
40+
Interview Questions
8
Categories
100%
Production-Grade
🔌

Designing a RESTful API with Best Practices

IntermediateAPI Design

Design a scalable, maintainable RESTful API following industry best practices and standards.

🎯 Key Topics to Master:

✓REST Principles & Constraints
✓Resource Modeling & URL Design
✓HTTP Methods & Status Codes
✓Versioning Strategies
✓Authentication & Authorization
✓Rate Limiting & Throttling

💡 Common Interview Questions:

  • 1.What are the key principles of REST?
  • 2.How do you handle API versioning?
  • 3.What is the difference between PUT and PATCH?
  • 4.How do you implement pagination for large datasets?
  • 5.What strategies prevent API abuse?

🔧 Technical Concepts:

HATEOAS and hypermediaOAuth 2.0 and JWTAPI gateway patternsOpenAPI/Swagger documentationCORS and security headers
🏗️

Microservices Architecture Implementation

AdvancedMicroservices

Design and implement a microservices architecture with proper service boundaries and communication patterns.

🎯 Key Topics to Master:

✓Service Decomposition Strategies
✓Inter-Service Communication
✓API Gateway & Service Mesh
✓Data Management Patterns
✓Service Discovery
✓Distributed Tracing

💡 Common Interview Questions:

  • 1.How do you determine service boundaries?
  • 2.What are the tradeoffs of synchronous vs asynchronous communication?
  • 3.How do you handle distributed transactions?
  • 4.What is the saga pattern?
  • 5.How do you manage shared data across services?

🔧 Technical Concepts:

REST, gRPC, and message queuesCircuit breaker patternDatabase per service patternEvent-driven architectureService mesh (Istio, Linkerd)
⚡

Database Query Optimization & Indexing

AdvancedDatabase Optimization

Optimize database performance through proper indexing, query optimization, and schema design.

🎯 Key Topics to Master:

✓Index Types & Strategies
✓Query Execution Plans
✓Normalization vs Denormalization
✓Partitioning & Sharding
✓Connection Pooling
✓N+1 Query Problem

💡 Common Interview Questions:

  • 1.How do you identify slow queries?
  • 2.What is the difference between clustered and non-clustered indexes?
  • 3.When should you denormalize data?
  • 4.How do you handle database hotspots?
  • 5.What are covering indexes?

🔧 Technical Concepts:

EXPLAIN and query analysisB-tree and hash indexesQuery hints and optimizationDatabase statisticsRead replicas and write scaling
💾

Implementing Multi-Layer Caching Strategy

IntermediateCaching

Design a comprehensive caching strategy with multiple layers to improve application performance.

🎯 Key Topics to Master:

✓Cache Levels (CDN, Application, Database)
✓Cache Invalidation Strategies
✓Redis & Memcached
✓Cache-Aside vs Write-Through
✓TTL & Eviction Policies
✓Cache Stampede Prevention

💡 Common Interview Questions:

  • 1.What are the different cache eviction policies?
  • 2.How do you handle cache invalidation?
  • 3.What is cache stampede and how do you prevent it?
  • 4.When should you use Redis vs Memcached?
  • 5.How do you ensure cache consistency?

🔧 Technical Concepts:

LRU, LFU eviction algorithmsCache warming strategiesDistributed cachingCache-aside patternBloom filters for cache
⏱️

Building Scalable Background Job Processing

AdvancedAsync Processing

Implement a robust background job processing system for handling asynchronous tasks at scale.

🎯 Key Topics to Master:

✓Message Queue Architecture
✓Job Scheduling & Prioritization
✓Retry & Error Handling
✓Dead Letter Queues
✓Idempotency & Exactly-Once Processing
✓Monitoring & Observability

💡 Common Interview Questions:

  • 1.What are the differences between RabbitMQ, Kafka, and SQS?
  • 2.How do you ensure job idempotency?
  • 3.What strategies handle job failures?
  • 4.How do you prioritize jobs?
  • 5.What is backpressure and how do you handle it?

🔧 Technical Concepts:

Worker pool patternsPoison pill patternMessage acknowledgmentJob retry with exponential backoffDistributed job scheduling
🔐

Implementing Authentication & Authorization

AdvancedSecurity

Build secure authentication and authorization systems with modern standards and best practices.

🎯 Key Topics to Master:

✓OAuth 2.0 & OpenID Connect
✓JWT & Session Management
✓Role-Based Access Control (RBAC)
✓Multi-Factor Authentication
✓Password Security & Hashing
✓API Key Management

💡 Common Interview Questions:

  • 1.What is the difference between authentication and authorization?
  • 2.How does OAuth 2.0 work?
  • 3.What are the security considerations for JWT?
  • 4.How do you implement RBAC?
  • 5.What is the difference between sessions and tokens?

🔧 Technical Concepts:

bcrypt and password hashingRefresh token rotationPKCE for mobile appsClaims-based authorizationSecurity token service (STS)
🔄

Real-Time Communication with WebSockets

IntermediateReal-Time Systems

Implement real-time bidirectional communication using WebSockets for live updates and notifications.

🎯 Key Topics to Master:

✓WebSocket Protocol & Handshake
✓Connection Management
✓Message Broadcasting
✓Scaling WebSocket Connections
✓Fallback Mechanisms (Polling, SSE)
✓Authentication & Security

💡 Common Interview Questions:

  • 1.What are the differences between WebSockets and HTTP?
  • 2.How do you scale WebSocket connections horizontally?
  • 3.What are fallback options when WebSockets are not available?
  • 4.How do you handle connection drops?
  • 5.What security concerns exist with WebSockets?

🔧 Technical Concepts:

Socket.io and SignalRRedis Pub/Sub for scalingHeartbeat and ping/pongMessage queuing for offline clientsServer-sent events (SSE)
🚦

Designing High-Throughput Rate Limiter

AdvancedScalability

Build a distributed rate limiting system to protect APIs from abuse and ensure fair resource allocation.

🎯 Key Topics to Master:

✓Rate Limiting Algorithms
✓Token Bucket & Leaky Bucket
✓Sliding Window Counters
✓Distributed Rate Limiting
✓Redis-Based Implementation
✓Graceful Degradation

💡 Common Interview Questions:

  • 1.What are the different rate limiting algorithms?
  • 2.How do you implement distributed rate limiting?
  • 3.What is the difference between throttling and rate limiting?
  • 4.How do you handle rate limiting across multiple servers?
  • 5.What response should be returned when rate limit is exceeded?

🔧 Technical Concepts:

Fixed window vs sliding windowRedis atomic operationsLua scripting for atomicityRate limit headersAdaptive rate limiting

📚 How to Use This Path

1. Study Each Use Case

Go through each scenario systematically. Understand the architecture, patterns, and tradeoffs.

2. Practice Interview Questions

Prepare answers for each question. Focus on explaining system design decisions and scalability.

3. Build Backend Systems

Implement at least 2-3 use cases as projects. Focus on production-ready code and best practices.

4. Master Backend Technologies

Gain hands-on experience with APIs, databases, and distributed systems. Be ready to discuss optimization.