Interview Q&A

Short answer: Ensures correctness, reliability, performance, and security of APIs. Postman → Manual and automated API testing, environment variables, collections. Swagger (OpenAPI) → Live documentation, mock servers, auto-generated client SDKs. Automates QA process and reduces bugs in production.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Caching is storing frequently used data temporarily to reduce server load and improve response time. Implementation methods: HTTP caching headers (Cache-Control, ETag, Expires). Reverse proxies (Varnish, NGINX). In-memory stores (Redis, Memcached). Client-side caching using 304 Not Modified.

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Content negotiation allows clients to specify desired response format. Uses HTTP headers: Accept: application/json → Request JSON. Accept: application/xml → Request XML. The server returns response in requested format (if supported). 👉 Example in ASP.NET Core: Add XML formatter with services.AddControllers() .AddXmlSerializerFormatters();

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: PI performance? A CDN caches and delivers static or semi-static content from edge servers close to users. Reduces latency and improves response times. Helps with traffic offloading, reducing load on origin servers. Supports DDoS protection and scaling under heavy loads. 👉 Cloudflare, Akamai, AWS CloudFront. Real-world example… (ShopNest) ShopNest… exposes REST APIs for cart and checkout. Controllers stay thin;…

Explain a bit more

business rules live in application services. PI performance? A CDN caches and delivers static or semi-static content from edge servers close to users. Reduces latency and improves response times. Helps with traffic offloading, reducing load on origin servers. Supports DDoS protection and scaling under heavy loads. 👉

Example code

Cloudflare, Akamai, AWS CloudFront. Real-world example… (ShopNest) ShopNest exposes REST APIs for cart and checkout. Controllers stay thin; business rules live in application services.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: A CDN caches and delivers static or semi-static content from edge servers close to users. Reduces latency and improves response times. Helps with traffic offloading, reducing load on origin servers. Supports DDoS protection and scaling under heavy loads. 👉 Example: Cloudflare, Akamai, AWS CloudFront.

Real-world example (ShopNest)

ShopNest exposes REST APIs for cart and checkout. Controllers stay thin; business rules live in application services.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Swagger/OpenAPI is a specification for defining REST APIs. Provides machine-readable and human-readable documentation. Enables automatic client SDK generation, testing, and validation. Improves team collaboration and consistency in API design.

Real-world example (ShopNest)

ShopNest exposes REST APIs for cart and checkout. Controllers stay thin; business rules live in application services.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Contains all endpoints, request/response formats, parameters, headers, and security details. Acts as a contract between client and server. Used for auto-generating documentation, client SDKs, and mock servers.

Real-world example (ShopNest)

ShopNest exposes REST APIs for cart and checkout. Controllers stay thin; business rules live in application services.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: RAML (RESTful API Modeling Language) → YAML-based specification for APIs. Focuses on design-first API approach. Differences with OpenAPI/Swagger: RAML is more design-oriented; Swagger is implementation-oriented. OpenAPI has better tooling support and community adoption.

Real-world example (ShopNest)

ShopNest exposes REST APIs for cart and checkout. Controllers stay thin; business rules live in application services.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Postman is a GUI tool for testing REST APIs. Features: Send HTTP requests (GET, POST, PUT, DELETE). Automate tests using Postman Collections. Generate documentation and mock servers. Supports environment variables and CI/CD integration.

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: PIs? Return a structured JSON response with: status → HTTP status code error → Short message details → Optional for debugging { "status": 400, "error": "Bad Request", "details": "Email is required" }

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.

Short answer: Return a structured JSON response with: status → HTTP status code error → Short message details → Optional details for debugging

Example code

{ "status": 400, "error": "Bad Request", "details": "Email field is required" }

Real-world example (ShopNest)

Creating an order is POST /api/orders → 201 with Location header. Fetching is GET /api/orders/{id} → 200 or 404.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.