Senior Backend Developer interview questions

How to use these questions

• Start with Screening questions — that's what you'll hear first (recruiter, HR).
• Prepare Technical questions with a concrete case from your experience that proves mastery.
• For Behavioral questions, use the STAR method (Situation, Task, Action, Result).
• Practice out loud — fluency is 50% of interview performance.

Technical (10)

1. 1

   Design the architecture of a payment platform handling 10K transactions/second.

   Hard

   Scenario — Distributed System Design

   Tip. Idempotency, saga pattern, exactly-once delivery, audit trail, compliance.

2. 2

   Microservices vs monolith: how do you make the choice and how to migrate?

   Medium

   Scenario — Distributed System Design

   Tip. Bounded contexts, strangler fig pattern, service mesh, data ownership.

3. 3

   How do you implement sharding for a high-growth database?

   Hard

   Scenario — Advanced Database Design

   Tip. Shard key selection, consistent hashing, cross-shard queries, rebalancing.

4. 4

   Explain database sharding strategies. How would you shard a large user table? What challenges arise and how do you mitigate them?

   Medium

   Scenario — Advanced Database Design

   Tip. Look for specific examples and data in the candidate's answer. Ask follow-up questions to probe deeper into their reasoning.

5. 5

   REST vs GraphQL vs gRPC: what selection criteria for a new service?

   Medium

   Scenario — Advanced API Architecture

   Tip. Use cases (mobile, inter-service, public), performance, tooling, team expertise.

6. 6

   Compare GraphQL and REST APIs. When would you choose GraphQL for a new project? What are the operational considerations?

   Medium

   Scenario — Advanced API Architecture

   Tip. Look for specific examples and data in the candidate's answer. Ask follow-up questions to probe deeper into their reasoning.

7. 7

   Describe an event-driven architecture with message queue. What pitfalls to avoid?

   Hard

   Scenario — Scalability Patterns

   Tip. At-least-once vs exactly-once, dead letter queues, ordering, idempotency, backpressure.

8. 8

   Explain horizontal scaling vs vertical scaling. How would you architect an application to support 100x growth in user base?

   Medium

   Scenario — Scalability Patterns

   Tip. Look for specific examples and data in the candidate's answer. Ask follow-up questions to probe deeper into their reasoning.

9. 9

   How do you implement a zero-trust architecture for your microservices?

   Hard

   Scenario — Advanced Backend Security

   Tip. mTLS, service mesh, JWT propagation, least privilege, secrets rotation.

10. 10

    Design a comprehensive security architecture addressing OWASP Top 10 vulnerabilities. How would you implement defense in depth?

    Medium

    Scenario — Advanced Backend Security

    Tip. Look for specific examples and data in the candidate's answer. Ask follow-up questions to probe deeper into their reasoning.

Behavioral (6)

1. 1

   Describe a situation where you had to collaborate with a difficult team

   Medium

   Scenario — Teamwork & Collaboration

   Tip. Use STAR. Focus on your role as facilitator and results achieved despite difficulties.

2. 2

   How do you handle disagreements within a team?

   Easy

   Scenario — Teamwork & Collaboration

   Tip. Show your listening skills, consensus-seeking and focus on common goal.

3. 3

   Tell me about a professional conflict you resolved

   Medium

   Scenario — Conflict Resolution

   Tip. STAR required. Show empathy, communication and win-win solution.

4. 4

   Tell me about a major conflict you handled at work.

   Medium

   Scenario — Conflict Resolution

   Tip. STAR: situation, both sides' positions, resolution approach, result.

5. 5

   Give an example where you took the lead without being required to

   Medium

   Scenario — Leadership Examples

   Tip. Show initiative, impact and how you brought others along.

6. 6

   Tell me about a situation where you demonstrated leadership without formal title.

   Medium

   Scenario — Leadership Examples

   Tip. Initiative, taking responsibility, mobilizing others, collective result.

Situational (4)

1. 1

   Tell me about a situation with an unhappy client

   Medium

   Scenario — Handling Difficult Clients/Customers

   Tip. STAR. Show active listening, empathy, proposed solution and follow-up.

2. 2

   How do you handle an unhappy client?

   Medium

   Scenario — Handling Difficult Clients/Customers

   Tip. Active listening, empathy, factualizing the problem, concrete action plan.

3. 3

   How did you handle a project with an impossible deadline?

   Medium

   Scenario — Managing Tight Deadlines

   Tip. Show prioritization, proactive communication and value delivery despite constraints.

4. 4

   You have 3 days to deliver what would take you 5. What do you do?

   Medium

   Scenario — Managing Tight Deadlines

   Tip. Negotiate scope, prioritize essentials, communicate transparently.

Leadership (4)

1. 1

   How do you manage an underperforming team member?

   Medium

   Scenario — People Management

   Tip. Show constructive approach: clear feedback, improvement plan, regular follow-up.

2. 2

   Describe your management style.

   Medium

   Scenario — People Management

   Tip. Authentic, examples, awareness of your strengths and watch points.

3. 3

   What is the most important strategic aspect of your last role?

   Medium

   Scenario — Strategic Thinking

   Tip. Vision, structuring choices, long-term impact.

4. 4

   How do you balance short and long term?

   Hard

   Scenario — Strategic Thinking

   Tip. Explicit trade-offs, dedicated resources, communication.

Case Studies (1)

1. 1

   How would you design a real-time notification system?

   Hard

   Scenario — System Design

   Tip. Clarify requirements, propose architecture, discuss trade-offs and scalability.

Screening (2)

1. 1

   Tell me about yourself

   Easy

   Scenario — Tell Me About Yourself

   Tip. Structure: present (current role), past (key background), future (why this role). Max 2 min.

2. 2

   Walk me through your resume

   Easy

   Scenario — Walk Me Through Your Resume

   Tip. Chronological, focus on transitions and progression. Explain career choices.

Negotiations (2)

1. 1

   What are your salary expectations?

   Medium

   Scenario — Salary Negotiation (New Job)

   Tip. Give a market-based range. Justify with your added value.

2. 2

   Which elements of the package are most important to you?

   Easy

   Scenario — Compensation Package Discussion

   Tip. Be honest but flexible. Show you understand total compensation.

Cultural Fit (2)

1. 1

   What type of work environment allows you to perform at your best?

   Easy

   Scenario — Company Culture Alignment

   Tip. Be authentic but align with company culture (if you know it).

2. 2

   What attracts you to our company culture?

   Easy

   Scenario — Company Culture Alignment

   Tip. Prior research, aligned values, concrete examples.

Career Dev (2)

1. 1

   How did you handle an internal job change?

   Medium

   Scenario — Internal Transfer Discussion

   Tip. Honesty, transparency with old manager, clean transition.

2. 2

   Why an internal transfer rather than leaving?

   Easy

   Scenario — Internal Transfer Discussion

   Tip. Cultural continuity, internal opportunity, leveraging existing knowledge.

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