How I Interview Backend Engineers: A Focus on Fundamentals
I interview backend engineers regularly, and over time, I’ve refined my approach.
This is a thoughtful approach to interviewing backend engineers that prioritizes foundational knowledge over specific technological implementations.
Let me explain on why each of these focus areas is valuable:
What I don’t focus on:
❌ Specific libraries or frameworks.
❌ Favorite programming languages.
❌ Trendy tools that may not last.
Why? These are often fleeting. Strong engineers can learn new tools quickly if they have solid fundamentals.
What I do focus on:
Here’s my core checklist for evaluating backend engineers:
✅ System Design — Scalability, trade-offs, and real-world architecture.
✅ HTTP Concepts — REST, GraphQL, caching, and performance.
✅ API Versioning & Lifecycle — How APIs evolve over time.
✅ Security — Authentication, authorization, and data protection.
✅ Concurrency & Scalability — Multithreading, async processing.
✅ Database Optimization — Query tuning, indexing, schema design.
✅ Observability — Logging, monitoring, and debugging strategies.
System Design
- Tests candidates’ ability to make architectural decisions that balance scalability, reliability, and maintainability
- Reveals how they think about trade-offs and requirements gathering
- Shows if they can communicate technical concepts clearly
HTTP & API Concepts
- Critical since most modern backends are built around APIs
- Tests understanding of statelessness, idempotency, and resource modeling
- Shows if they grasp different API paradigms’ strengths and weaknesses
Auth & Security
- Essential for protecting sensitive data and resources
- Demonstrates awareness of common vulnerabilities and best practices
- Shows understanding of identity management and access control
Concurrency & Scalability
- Crucial for building systems that can handle growing load
- Tests understanding of race conditions, deadlocks, and resource contention
- Shows ability to design for horizontal scaling
Database Knowledge
- Foundation for data-driven applications
- Tests understanding of data modeling, normalization, and indexing
- Shows awareness of query performance implications
Logging & Monitoring
- Often overlooked but critical for production systems
- Shows understanding of observability and debugging
- Demonstrates awareness of operational concerns
Bonus points for:
🌍 Distributed Systems — Microservices, event-driven patterns.
☁️ Cloud Technologies — AWS, GCP, Azure, serverless.
🚀 CI/CD Pipelines — DevOps mindset, automated deployments.
Why This Approach Works
Engineers with strong fundamentals can:
✅ Adapt to any technology.
✅ Learn new tools quickly.
✅ Contribute meaningfully from day one.
💬 What’s your approach to backend engineering interviews? Would love to hear different perspectives! 🚀
Want Specific Questions?
If you’re interested, I can share specific interview questions or scenarios I’ve found effective for evaluating these areas. For example
- A system design question that tests scalability and trade-offs.
- A concurrency problem to assess async processing skills.
- A database optimization scenario to evaluate query tuning.
Key Takeaways
To make this easy to remember, here’s a quick summary:
- Focus on fundamentals over specific tools.
- Core areas: System Design, HTTP/APIs, Security, Concurrency, Databases, Observability.
- Bonus: Distributed Systems, Cloud, CI/CD.
- Why it works: Strong fundamentals = adaptable, impactful engineers
#BackendDevelopment #SoftwareEngineering #SystemDesign #Hiring #Scalability #APIs #DevOp
Conclusion
This details approach helps identify engineers who not only understand backend development deeply but can also adapt to changing technologies and contribute to building robust, scalable systems.
The goal is to find engineers who can:
- Think systematically about complex problems
- Make informed architectural decisions
- Consider security and performance implications
- Adapt to new technologies effectively
- Contribute meaningfully from day one
