Frontend Backend Integration Through APIs Questions

Understanding how frontend components interact with backend APIs using HTTP requests (fetch, axios, etc.), handling asynchronous responses and errors, managing data flow from API responses to UI updates. Ability to design APIs that frontend needs and implement corresponding client-side code to consume them properly.

EasyTechnical

46 practiced

Explain the semantics and typical usage of the HTTP methods GET, POST, PUT, PATCH, and DELETE. For each method:- describe idempotency and safety- give a concrete frontend action example (e.g., form submission, partial update)- explain when you'd choose PATCH vs PUTAlso include common status codes returned for success and failure for each method.

MediumTechnical

53 practiced

Design a consistent error response format for your APIs and implement a client-side interceptor (axios or fetch wrapper) that:- maps server errors to user-friendly messages- triggers behavior for specific codes (e.g., refresh on 401)- logs diagnosticsProvide an example error JSON and pseudocode for the interceptor.

MediumTechnical

54 practiced

Design a client-side strategy in JavaScript to prevent multiple simultaneous refresh-token calls when several API requests receive 401 at the same time. Describe the algorithm, how pending requests are queued and retried after refresh, and show pseudocode for implementing this with an axios interceptor or a fetch wrapper.

HardTechnical

48 practiced

As a senior/frontend lead you must define and drive API integration standards across multiple teams. Outline your approach to integration governance: standards you would set (schema, error formats, versioning), how you'd enforce them (CI checks, codegen, SDKs), how to onboard teams, and which metrics you'd track to measure adoption and integration quality.

MediumBehavioral

42 practiced

Tell me about a time when you and backend engineers disagreed about an API contract or endpoint design that affected the frontend. Describe the situation (context), the specific technical disagreement, steps you took to resolve it, the decision made, and what you learned (STAR format). Focus on communication, compromise, and how you ensured a smooth integration.

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