Question 1

Compare REST and GraphQL. What are the real tradeoffs and which would you choose for a mobile app with a complex data model?

Accepted Answer

This is a medium-difficulty Backend Developer interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Question 2

Explain database indexing. How does a B-tree index work and when does adding an index make performance worse?

Accepted Answer

This is a medium-difficulty Backend Developer interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Question 3

What is a message queue and when would you use one over a synchronous API call? Explain at least one failure scenario it solves.

Accepted Answer

This is a medium-difficulty Backend Developer interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Question 4

How do you run a database schema migration in production with zero downtime on a table that has 500M rows?

Accepted Answer

This is a hard-difficulty Backend Developer interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Question 5

Walk through the OAuth 2.0 authorization code flow. How do JWTs fit in and what are the security risks of storing them in localStorage?

Accepted Answer

This is a medium-difficulty Backend Developer interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Question 6

What is connection pooling? What happens to your application when the pool is exhausted?

Accepted Answer

This is a easy-difficulty Backend Developer interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Question 7

How do you design an idempotent API endpoint? Walk through a payment processing example where idempotency is critical.

Accepted Answer

This is a hard-difficulty Backend Developer interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Question 8

Explain the difference between horizontal and vertical scaling. At what point does horizontal scaling introduce new engineering problems?

Accepted Answer

This is a easy-difficulty Backend Developer interview question commonly asked at senior software engineering interviews. Study this question and practice answering it with an AI mock interview on Zavnia.

Backend Developer Interview Questions

Interview Questions

Compare REST and GraphQL. What are the real tradeoffs and which would you choose for a mobile app with a complex data model?

Explain database indexing. How does a B-tree index work and when does adding an index make performance worse?

What is a message queue and when would you use one over a synchronous API call? Explain at least one failure scenario it solves.

How do you run a database schema migration in production with zero downtime on a table that has 500M rows?

Walk through the OAuth 2.0 authorization code flow. How do JWTs fit in and what are the security risks of storing them in localStorage?

What is connection pooling? What happens to your application when the pool is exhausted?

How do you design an idempotent API endpoint? Walk through a payment processing example where idempotency is critical.

Explain the difference between horizontal and vertical scaling. At what point does horizontal scaling introduce new engineering problems?