Backend Engineer

Implement middleware for your APIs to handle authentication and authorization. Walk through what you would check before allowing a request.

Your checkout calls a payment provider. How would you handle a request that times out?

Before creating an order, your API checks that a product is in stock. How would you implement the reservation?

Product pages are slow. You add a cache for product information, including prices.

A queue consumer processes order events and grants loyalty points.

An authenticated user requests an invoice by its ID. Which access checks should the API perform?

A frequently used database query is slow. What would you investigate before adding an index?

Limit each account to 100 API requests per minute.

Create an order in a database and publish an order-created event to a broker.

Design pagination for a feed sorted by newest first.

Your API calls three downstream services before returning a response.

Rename a database column used by an API while keeping the service available.

Your system sends writes to a primary database and reads to replicas.

Design an API for uploading large user files over unreliable connections.

Add request logging to make production API failures easier to investigate.