Question bank

Interview questions, with guidance on how to answer

834 questions across 64 roles. Open one to see what a strong answer includes and common slips, then drill it out loud with Ava. New to answer structure? Start with the learning hub.

834 questions.

CaseEntry levelBackend Engineer
What is a database index, and how would you decide whether a column needs one?
Tests: Databases & data modelling
TechnicalEntry levelBackend Engineer
How do you protect a web application from someone sending malicious input, such as an SQL injection attack?
Tests: Security fundamentals
BehaviouralMid levelBackend Engineer
Tell me about a time you changed a database schema on a live system. How did you do it without downtime?
Tests: Databases & data modelling
TechnicalMid levelBackend Engineer
An endpoint starts timing out in production at peak hours. How would you investigate, and what would you look at first?
Tests: Reliability & observability
TechnicalMid levelBackend Engineer
How do you handle two requests trying to update the same record at the same time?
Tests: Performance & concurrency
TechnicalMid levelBackend Engineer
How do you evolve an API that other teams depend on without breaking them?
Tests: API design
TechnicalMid levelBackend Engineer
How do you handle secrets like database passwords and access keys in your services?
Tests: Security fundamentals
System designSeniorBackend Engineer
How would you design a system that sends order confirmation emails reliably, even if the email provider is down for a while?
Tests: Distributed systems & scalability
TechnicalSeniorBackend Engineer
When would you split a monolith into separate services, and when would you argue against it?
Tests: Distributed systems & scalability
TechnicalSeniorBackend Engineer
How do you decide what to alert on for a service you own, so the on-call engineer is woken only for things that matter?
Tests: Reliability & observability
BehaviouralAny levelBackend Engineer
Tell me about an incident you were part of. What was your role, and what changed afterwards?
Tests: Ownership
BehaviouralAny levelBackend Engineer
Tell me about a time you had to agree on an interface or contract with another team that had different priorities. How did you get there?
Tests: Cross-team communication
TechnicalEntry levelFull-Stack Engineer
Walk me through how you would build a page that shows a list of items from a server, including what the user sees while it loads.
Tests: Frontend development
TechnicalEntry levelFull-Stack Engineer
What happens, step by step, when a user submits a sign-up form on a website, from the browser all the way to the database?
Tests: Backend & API development
TechnicalEntry levelFull-Stack Engineer
If you were storing users, their posts and comments on those posts, how would you set up the tables and relationships?
Tests: Data modelling & databases
TechnicalMid levelFull-Stack Engineer
Tell me about a feature you built from the database all the way to the user interface. What decisions did you make along the way?
Tests: End-to-end feature delivery
TechnicalMid levelFull-Stack Engineer
A user reports that saving their profile sometimes fails with no error message. How would you figure out whether it's a frontend or backend problem?
Tests: Testing & debugging across the stack
TechnicalMid levelFull-Stack Engineer
How do your changes usually get from your machine to production, and what checks happen along the way?
Tests: Deployment & cloud basics
TechnicalMid levelFull-Stack Engineer
How do you handle authentication in a web app, and where do you store the user's session or token?
Tests: Backend & API development
TechnicalMid levelFull-Stack Engineer
How do you keep the frontend's data in sync with the server, for example right after a user edits something?
Tests: Frontend development