TOPIC OVERVIEW

NestJS/API Design

Design NestJS APIs that are predictable, maintainable, and easy for other developers to consume.

18 QuestionsAdvancedHigh Priority ~13 min read

Building an API is not just about creating routes that return data. A good API needs consistent resource naming, HTTP methods, status codes, validation, error responses, pagination, and a clear contract between the client and server.

NestJS gives you tools such as DTOs, pipes, controllers, serialization, and API documentation support to help build that contract. The real challenge is deciding how these pieces should be combined to create an API that remains easy to change as the application grows.

What you'll walk away knowing

How to design consistent REST endpoints

How DTOs and validation create clear API contracts

How to handle pagination, errors, and status codes

How to design APIs that remain maintainable as they grow

1How do you implement content negotiation so an endpoint returns JSON or CSV based on the Accept header in NestJS?Intermediate 2How do you implement discriminated union body validation where the DTO shape depends on a type field in NestJS?Intermediate 3How do you set a default version so unversioned requests are handled by a specific version in NestJS?Intermediate 4How do you handle a route where the param can be either a numeric ID or the literal string 'me' in NestJS?Intermediate 5How do you handle multi-value query parameters (arrays) in NestJS?Intermediate 6How do you implement a standard paginated response envelope across all list endpoints in NestJS?Intermediate 7How do you document DTO properties for Swagger and handle optional vs required fields in NestJS?Intermediate 8What decorators does NestJS provide for route parameters and how do they differ from query params?Intermediate 9How do you set HTTP status codes, response headers, and redirects in NestJS without using @Res()?Intermediate 10What versioning strategies does NestJS support and how do you enable versioning?Intermediate 11How do you apply versioning at controller and method level in NestJS and how do you mark a route as version-neutral?Intermediate 12What is the difference between @Param('id') and @Param() with no argument in NestJS?Intermediate 13How do you set up Swagger in a NestJS application and annotate your controllers?Intermediate 14What is the difference between @Body(), @Body('field'), and using a full DTO class in NestJS?Intermediate 15How do you extract and type query parameters in NestJS including optional ones with defaults?Intermediate 16How do you handle HATEOAS hypermedia links in NestJS REST responses?Intermediate 17How do wildcard and optional route segments work in NestJS?Intermediate 18How do you stream a large file or dataset as a response without loading it fully into memory in NestJS?Intermediate 19How do you handle raw body access for webhook signature verification in NestJS?Intermediate 20How do you implement API rate limiting per user or per IP in NestJS?Intermediate 21How do you build a reusable pagination and sorting query DTO that can be extended by feature-specific DTOs in NestJS?Intermediate 22How do you implement idempotency keys for POST requests to prevent duplicate operations in NestJS?Intermediate 23What is the recommended file structure for versioned controllers in a NestJS project?Intermediate 24How do you implement a PATCH endpoint correctly with partial validation using PartialType in NestJS?Intermediate 25How do you use ClassSerializerInterceptor with @Exclude() and @Expose() to control response shape in NestJS?Intermediate

All Topics

1

Dependency Injection

2

Request Lifecycle

Exception Handling

3

4

Database and ORM

5

Authentication and Authorization

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