#apis

16 apis interview questions, asked at Apple, Airbnb, Amazon and 8 more companies. Last asked Oct 2026.

Ingest MCAP driving logs and query them by timestampCodingBuild a small data service over recorded vehicle drives, with an AI coding assistant allowed. Each drive (a run) is stored as an MCAP file: timestamped messages on several topics…
Last asked Oct 2026
Explore a friend graph through a remote API with few callsCodingYou cannot read a social graph directly; the only access is getfriends(userid), a remote call that returns a user's friends and costs a network round trip. Write code that…
Last asked Sep 2026
Send requests in batches of five and retry failures after a delayCodingDeliver a list of requests to an API that accepts at most five requests per call. Some requests in a call can fail; a failed request may be retried only after its own delay has…
Last asked Sep 2026
Design a Terraform provider for a cloud resourceSystem designYou work on infrastructure at a cloud provider. Customers want to manage one of your resources with Terraform: declare it in config, apply it, change it later and destroy it the…
Last asked Sep 2026
CSV upload endpoint that classifies rows with an LLMCodingA practical round: build a service endpoint that takes an uploaded CSV, sends each row to a language model to classify it, and returns the results as JSON. Write the prompt and…
Last asked Jul 2026
Design an order relay service in front of a broker APISystem designClients send buy and sell orders with a deadline to your service, which forwards them to a third-party broker, tracks each order until it fills, and cancels whatever has not…
Last asked Apr 2026
Find the shortest queue with few callsCodingYou can learn the length of each of several queues only through a call that is expensive. Find the shortest queue while making as few calls as you can, and explain the trade-off…
Last asked Apr 2026
Idempotent request handling with idempotency keysCodingImplement a request handler that uses client-supplied idempotency keys so that retrying the same request returns the original result instead of doing the work twice. Handle two…
Last asked Feb 2026
Precision and recall at k from a flaky top-k APICodingAn API returns a model's top-k predictions for each query, but calls sometimes fail or time out. Compute precision and recall against the true labels across a set of queries, with…
Last asked Feb 2026
Build a text summarization API serviceCodingWith an AI assistant available, build a small production-style web service with FastAPI: POST /summarize takes JSON {"text": ...} and returns {"summary": ...}. Add input…
Last asked Jan 2026
Design an online Minesweeper platformSystem designDesign a platform where people play Minesweeper online. Cover generating boards, the API for revealing and flagging cells, where game state lives and who is trusted to know mine…
Last asked Nov 2025
Serve happy number checks at scaleSystem designA service answers whether a number eventually reaches 1 when you keep replacing it with the sum of the squares of its digits. Scale it to a large volume of requests: caching or…
Last asked Oct 2025
Design a basic task management systemSystem designDesign a simple task management system: users create tasks, assign them, set due dates and statuses, and see their lists. Cover the API, the data model, notifications for due…
Last asked Sep 2025
Build a booking widget with live pricingCodingBuild a small reservation widget for a listing, front end and a simple back end. Pick check-in and check-out dates and the number of adults and children; show the total price…
Last asked Aug 2025
Design a waitlist for in-demand listingsSystem designWhen a popular listing is not available for the dates a guest wants, the guest can join a waitlist. Design the API and system behind it: joining and leaving, detecting when the…
Last asked Jul 2025
Write a robust REST API methodCodingWrite one REST API method from end to end: validate the input, handle the request, return proper status codes and errors, and cover retries, timeouts and logging.
Last asked Jul 2025