Software Engineer Interview Questions

1.1System design fundamentals - components, interfaces, and designing for scalability and maintainability

1.2Architectural patterns - monolith, microservices, event-driven, and when to use each

1.3API design - RESTful principles, GraphQL, versioning, and designing APIs that are easy to consume

1.4Technical debt - identifying it, quantifying it, and making the case for paying it down

2.1Concurrency and parallelism - threads, async programming, race conditions, and how to handle them

2.2Memory management - stack vs heap, garbage collection, and avoiding memory leaks

2.3Functional programming concepts - immutability, pure functions, and where they improve code

2.4Performance optimisation - profiling, identifying bottlenecks, and writing efficient code

3.1Advanced SQL - window functions, CTEs, query optimisation, and execution plans

3.2Database performance - indexing strategies, query analysis, and avoiding N+1 problems

3.3Data modelling - designing schemas for complex domains, migrations, and schema evolution

3.4Caching strategies - in-memory caches, CDN, application-level caching, and cache invalidation

4.1Distributed systems concepts - CAP theorem, consistency, availability, and partition tolerance

4.2Messaging and event streaming - queues, pub-sub, and asynchronous communication patterns

4.3Service communication - synchronous vs asynchronous, circuit breakers, and handling failures

4.4Data consistency in distributed systems - eventual consistency, sagas, and distributed transactions

5.1OWASP Top 10 - the most common vulnerabilities and how to prevent them in your code

5.2Authentication and authorisation - OAuth 2.0, JWT, RBAC, and implementing them securely

5.3Secure coding practices - input validation, parameterised queries, and not trusting user input

5.4Security testing - SAST, DAST, and security code review practices

6.1Testing pyramid - unit, integration, and end-to-end tests and the right balance between them

6.2Test-driven development - how to write tests first and the discipline it requires

6.3Contract testing - ensuring services integrate correctly especially in a microservices architecture

6.4Testing in production - feature flags, canary releases, and monitoring for regressions

7.1Cloud architecture - designing systems on cloud for reliability and cost efficiency

7.2Infrastructure as code - Terraform and managing infrastructure like software

7.3Containerisation and orchestration - Docker, Kubernetes, and running services at scale

7.4Observability - logging, metrics, tracing, and building systems you can debug in production

8.1Code review - how to review code thoroughly, give useful feedback, and build a high-quality codebase

8.2Technical documentation - architecture decision records, runbooks, and writing for future engineers

8.3Agile in practice - how effective engineers operate in sprints, manage their work, and communicate

8.4On-call and incident management - responding to production issues, post-mortems, and building resilience

9.1Moving from engineer to senior engineer - what changes and how to accelerate the transition

9.2Technical mentoring - helping junior engineers grow without doing the work for them

9.3Influencing technical direction - proposing improvements, getting buy-in, and driving change

9.4Staying current - how to keep learning in a fast-moving industry without burning out

10.1Coding interviews - data structures, algorithms, and how to perform under pressure

10.2System design interviews - how to approach open-ended design questions at mid-level

10.3Behavioural interviews - ownership, collaboration, technical decisions, and handling disagreement

10.4Salary negotiation, evaluating a tech stack and team, and questions that reveal whether it is a good role