Migration from REST to GraphQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main difference between REST and GraphQL in terms of data fetching?

REST uses multiple endpoints for different resources, often requiring multiple requests. GraphQL uses a single endpoint and allows clients to request exactly the data they need in one query.

beginner

Why might migrating from REST to GraphQL improve client performance?

Because GraphQL lets clients request only the data they want, it reduces over-fetching and under-fetching, which can lower the number of requests and the amount of data transferred.

intermediate

What is a common first step when migrating a REST API to GraphQL?

Identify the existing REST endpoints and their data structures, then design a GraphQL schema that represents the same data and relationships in a flexible way.

intermediate

How does GraphQL handle versioning compared to REST?

GraphQL typically avoids versioning by evolving the schema with new fields and deprecating old ones, while REST often uses versioned endpoints like /v1/, /v2/.

intermediate

What is a resolver in GraphQL and why is it important during migration?

A resolver is a function that fetches the data for a specific field in a GraphQL query. During migration, resolvers connect the GraphQL schema to the existing data sources, including REST endpoints or databases.

What does GraphQL use to allow clients to specify exactly what data they want?

A A single flexible query language

B Multiple fixed endpoints

C HTTP headers

D URL parameters

GraphQL uses a single query language that lets clients specify exactly which fields and data they want.

When migrating from REST to GraphQL, what is the first thing you should do?

A Change the frontend without backend changes

B Rewrite all backend code from scratch

C Remove all REST endpoints immediately

D Design the GraphQL schema based on existing REST endpoints

Designing the GraphQL schema based on existing REST endpoints helps map current data structures before migrating.

How does GraphQL typically handle API versioning?

A By creating new endpoints for each version

B By using query parameters to specify versions

C By evolving the schema and deprecating fields

D By requiring clients to upgrade manually

GraphQL evolves the schema over time and deprecates old fields instead of creating new endpoints.

What role do resolvers play in a GraphQL API?

A They fetch and return data for query fields

B They format the HTTP response headers

C They handle user authentication

D They define the API version

Resolvers are functions that fetch and return the data for each field requested in a GraphQL query.

Which of the following is a benefit of migrating from REST to GraphQL?

A Clients can over-fetch data easily

B Clients can get all needed data in a single request

C Multiple endpoints reduce complexity

D GraphQL requires no backend changes

GraphQL allows clients to get all the data they need in one request, reducing multiple calls.

Explain the key steps involved in migrating a REST API to GraphQL.

Think about how you map existing data and connect it to GraphQL.

Describe how GraphQL improves client-server communication compared to REST.

Focus on how clients ask for data and how much data they get.