Interview questions
Backend Developer interview questions
53 realistic questions across technical, behavioural, HR, situational and role-specific categories. Questions only — join free to unlock model answers, quizzes and AI mock interviews.
Showing 25 of 53 questions
How do you decide between inheritance and composition in your code?
Technical
Beginner
Q1
How would you design a REST API for a high-traffic feature?
Technical
Intermediate
Q2
How would you diagnose and fix a slow database query?
Technical
Intermediate
Q3
How would you keep a page fast when traffic spikes?
Technical
Advanced
Q4
How would you secure an API against unauthorised access?
Technical
Advanced
Q5
How do you decide what to unit test versus integration test?
Technical
Intermediate
Q6
How would you prevent a race condition in a distributed system?
Technical
Advanced
Q7
Walk me through deploying a service with zero downtime.
Technical
Advanced
Q8
How would you implement an LRU cache to reduce database load for a frequently accessed user profile endpoint?
Technical
Beginner
Q233
How would you design a RESTful API endpoint to allow clients to partially update a user's profile (e.g., only email) without sending the entire resource?
Technical
Beginner
Q234
A colleague asks for help optimizing a slow query that joins three large tables and returns aggregated results. How would you diagnose and fix it?
Technical
Intermediate
Q235
How would you design a backend service to handle 10,000 concurrent WebSocket connections without blocking the event loop?
Technical
Intermediate
Q236
How would you design a distributed rate limiter that works across multiple API servers to prevent abuse of a public endpoint?
System Design
Advanced
Q237
Tell me about a time you demonstrated Behavioral Interview: Handling Conflict in Team Environments.
Behavioral
Beginner
Q238
What would you do if you faced this situation: Situational Interview: Debugging a Production Issue?
Situational
Intermediate
Q239
How would you handle Role-Specific: Implementing Authentication and Authorization on a typical day?
Role Specific
Intermediate
Q240
What does good practice look like when it comes to Professional Specific: Writing Clean, Maintainable Backend Code?
Professional Specific
Intermediate
Q241
How would you answer an interviewer asking about HR Screening: Career Motivation and Goals?
HR Screening
Beginner
Q242
A colleague asks for help normalizing a denormalized table that stores customer orders with repeated product details. How would you refactor it?
Technical
Intermediate
Q245
How would you ensure thread safety when multiple workers update a shared counter in a distributed backend system?
Technical
Intermediate
Q246
How would you design a scalable backend architecture for a real-time chat application that supports millions of concurrent users?
System Design
Advanced
Q247
Tell me about a time you demonstrated Behavioral: Handling Conflict in a Development Team.
Behavioral
Intermediate
Q248
What would you do if you faced this situation: Situational: Debugging Production Issues Under Pressure?
Situational
Advanced
Q249
How would you handle Role Specific: Implementing Authentication and Authorization on a typical day?
Role Specific
Intermediate
Q250
What does good practice look like when it comes to Professional Specific: Writing Clear and Maintainable Code?
Professional Specific
Beginner
Q251
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