GraphQL vs REST: Key Differences and Use Cases Quiz

Explore the fundamental differences between GraphQL and REST APIs, their strengths, and the scenarios where each is most effective. This quiz helps you understand core concepts, query structures, and typical use cases relevant to modern API development.

1. Flexible Data Retrieval

   Which advantage does GraphQL offer over REST when a client needs only specific fields from related resources, such as retrieving usernames but not email addresses from a user list?

   1. REST enables partial responses by default for every request.
   2. GraphQL requires multiple endpoints to access different data fields.
   3. REST and GraphQL are equally efficient for field selection.
   4. GraphQL allows clients to specify exactly which fields they need in a single query.

   Explanation: With GraphQL, clients have control over the exact fields included in the response, minimizing data transfer and improving efficiency. REST typically returns complete resources and often requires multiple endpoints or custom solutions for partial responses. Option two is incorrect because GraphQL does not separate field access by endpoint. REST does not natively support partial responses as in option three. Option four is misleading since REST cannot match GraphQL's flexibility in field-level selection.

2. API Versioning Approaches

   How does the approach to versioning typically differ between REST APIs and GraphQL APIs?

   1. Both REST and GraphQL always require separate endpoints for every version.
   2. REST APIs never change version, while GraphQL versions frequently.
   3. GraphQL requires a new endpoint for every API change, but REST does not.
   4. REST APIs usually add new endpoints or URIs for each version, while GraphQL evolves the schema without needing separate versions.

   Explanation: REST often uses explicit versions in the URI or separate endpoints for major updates, making versioning visible to clients. GraphQL, on the other hand, encourages backward-compatible schema changes without splitting into multiple endpoints. Option two incorrectly reverses the requirement. Option three inaccurately says both always need new endpoints. Option four is false, as both API styles can change over time, but in different ways.

3. Handling Over-fetching and Under-fetching

   What problem commonly associated with REST APIs does GraphQL address, particularly when clients receive too much or too little data in a response?

   1. Automatic data caching for every API call.
   2. Inability to handle binary data transfer between client and server.
   3. A lack of statelessness in HTTP requests.
   4. Over-fetching and under-fetching due to rigid endpoint structures.

   Explanation: REST endpoints often send more or less data than needed, causing clients to receive unnecessary information or request additional resources. GraphQL solves this by letting clients tailor their queries to exact data needs. Option two refers to a non-specific issue not unique to REST. Option three is incorrect, as neither REST nor GraphQL guarantees automatic caching. Option four is not relevant, since both API styles commonly use stateless HTTP requests.

4. Batching Requests

   When a client needs to fetch related data, like users and their associated posts, how do GraphQL and REST commonly differ in handling such requests?

   1. GraphQL requires chaining separate queries for related resources.
   2. REST combines all related data into a single request by default.
   3. GraphQL allows clients to fetch nested and related data in a single query, while REST often requires multiple HTTP requests.
   4. REST and GraphQL both prevent clients from querying nested resources.

   Explanation: A key feature of GraphQL is its ability to retrieve nested resources in one query, streamlining communication between client and server. REST’s architecture typically needs multiple requests to various endpoints to gather related data. Option two isn't correct because REST responses are usually resource-specific. Option three confuses GraphQL's approach, which supports nested queries without chaining. Option four misstates both approaches, as GraphQL explicitly supports querying nested resources.

5. Use Case Suitability

   In which use case would a REST API likely be more appropriate than GraphQL, considering simplicity and network constraints?

   1. Aggregating data from multiple sources with complex relationships.
   2. Implementing a dashboard that needs dynamic, tailored data structures.
   3. Building a simple public API for fixed resources like status codes and names.
   4. Developing a mobile app that requires highly customizable responses.

   Explanation: REST works well when the data structure is predictable and does not need customization, as in simple public APIs for static resources. GraphQL shines when clients require flexible queries or aggregation of related data, as seen in options two, three, and four. Those scenarios benefit from GraphQL's ability to provide just the data needed in a single response, making REST less ideal for those cases.