GraphQL Quiz ( Intermediate ) - All Questions

This medium-level GraphQL quiz is designed for developers who know GraphQL basics and want to deepen their understanding of schemas, resolvers, variables, pagination, error handling, and real-world API design. Ideal for interviews and practical frontend/backend GraphQL usage.

Question 1: What is the main purpose of GraphQL variables?

To cache queries
To pass dynamic values into queries
To define schema fields
To validate responses

Explanation: Variables allow dynamic values without changing the query structure.

Question 2: Why are GraphQL schemas strongly typed?

For faster rendering
For predictable API behavior
For database optimization
For caching responses

Explanation: Strong typing ensures predictable and validated data.

Question 3: Which problem does GraphQL pagination mainly address?

Authentication
Large data sets
Caching issues
Schema validation

Explanation: Pagination prevents fetching excessively large datasets.

Question 4: What is the role of a field resolver?

Define schema types
Fetch data for a specific field
Validate client queries
Cache responses

Explanation: Resolvers return data for individual fields.

Question 5: Why are arguments used in GraphQL fields?

To mutate schema
To filter or customize data
To define types
To cache queries

Explanation: Arguments allow fetching customized data.

Question 6: What does GraphQL introspection allow?

Query optimization
Runtime schema discovery
Caching control
Authorization

Explanation: Introspection allows clients to explore the schema.

Question 7: Why is over-fetching avoided in GraphQL?

Clients request only needed fields
Resolvers limit data size
Schemas hide fields
Servers block extra data

Explanation: Clients specify exactly what data they need.

Question 8: Which GraphQL type is best suited for mutation inputs?

Object type
Enum type
Input type
Scalar type

Explanation: Input types are designed for arguments.

Question 9: What happens if a resolver throws an error?

Server crashes
Only errors are returned
Partial data with errors may be returned
Query is ignored

Explanation: GraphQL can return partial data with errors.

Question 10: Why is schema-first design popular in GraphQL?

Better caching
Clear contract between client and server
Automatic resolvers
Less code

Explanation: Schema-first provides a clear API contract.

Question 11: Which directive is used to mark fields as deprecated?

@remove
@old
@deprecated
@ignore

Explanation: @deprecated marks fields as outdated.

Question 12: Why does GraphQL typically use a single endpoint?

Better security
Simpler API surface
Automatic caching
Improved performance

Explanation: A single endpoint simplifies API design.

Question 13: Which GraphQL feature supports conditional fields?

Fragments
Directives
Enums
Resolvers

Explanation: Directives like @include and @skip enable conditional fields.

Question 14: What is the purpose of GraphQL fragments?

Split APIs
Reuse query parts
Paginate data
Cache responses

Explanation: Fragments allow reusing field selections.

Question 15: Why should fragments be used carefully?

They break schemas
They can cause over-fetching
They increase query complexity
They disable caching

Explanation: Excessive fragments can make queries hard to read.

Question 16: Which GraphQL type represents a list of values?

Enum
Scalar
List
Object

Explanation: Lists represent arrays of values.

Question 17: What does a non-null list type [Type!]! mean?

Optional list and items
Non-null list with non-null items
Nullable list with required items
Required list with optional items

Explanation: Both the list and its items are non-null.

Question 18: Why should resolvers be kept lightweight?

For UI rendering
To avoid performance bottlenecks
To reduce schema size
To enable caching

Explanation: Heavy resolvers can slow down responses.

Question 19: What is N+1 problem in GraphQL?

Too many mutations
Repeated database queries per field
Large schema files
Multiple endpoints

Explanation: N+1 occurs when each field triggers a separate query.

Question 20: Which tool helps solve the N+1 problem?

REST
DataLoader
Fragments
Directives

Explanation: DataLoader batches and caches requests.

Question 21: Why are GraphQL responses predictable?

Fixed endpoints
Schema enforcement
Server caching
HTTP methods

Explanation: Schema enforces predictable response shapes.

Question 22: Which HTTP status code does GraphQL usually return on errors?

500 always
200 with error details
404
400 only

Explanation: GraphQL often returns 200 with error information.

Question 23: Why should authentication be handled outside resolvers?

Simpler schema
Separation of concerns
Better caching
Faster execution

Explanation: Auth logic is better handled via middleware/context.

Question 24: What is GraphQL context mainly used for?

Schema definition
Sharing request-level data
Caching responses
Defining queries

Explanation: Context shares data like auth info across resolvers.

Question 25: Which GraphQL feature helps with API evolution?

Versioning
Deprecation
Multiple endpoints
Breaking changes

Explanation: Deprecation allows gradual API evolution.

Question 26: Why should mutations be explicit?

For caching
To clearly signal data changes
For performance
For schema simplicity

Explanation: Mutations clearly represent data changes.

Question 27: What is the main benefit of client-driven queries?

Less backend work
Frontend flexibility
Better security
Simpler schemas

Explanation: Clients control exactly what data they need.

Question 28: Which GraphQL operation supports real-time features?

Query
Mutation
Subscription
Fragment

Explanation: Subscriptions enable real-time updates.

Question 29: Why are subscriptions commonly implemented with WebSockets?

Better security
Persistent connections
Simpler queries
Schema enforcement

Explanation: WebSockets allow real-time data push.

Question 30: What is a common drawback of deeply nested queries?

Schema errors
Performance impact
Authentication failure
Caching issues

Explanation: Deep nesting can increase execution cost.

Question 31: Why should GraphQL schemas be modularized?

Better UI rendering
Improved maintainability
Automatic caching
Reduced payload size

Explanation: Modular schemas scale better.

Question 32: What does GraphQL federation enable?

Multiple clients
Distributed schemas
Query batching
Caching

Explanation: Federation allows composing multiple schemas.

Question 33: Which approach improves GraphQL performance most?

More fields
Batching and caching
Schema expansion
Nested queries

Explanation: Batching and caching reduce backend load.

Question 34: Why should error messages be carefully designed?

For styling
For security and clarity
For caching
For pagination

Explanation: Errors should not expose sensitive details.

Question 35: Which GraphQL feature improves code reuse on the client?

Fragments
Resolvers
Enums
Inputs

Explanation: Fragments reuse query parts.

Question 36: Why is GraphQL considered self-documenting?

Automatic docs
Introspection support
Schema comments
Resolvers

Explanation: Introspection enables automatic documentation.

Question 37: Which practice helps prevent overly complex queries?

Query depth limiting
Schema expansion
More resolvers
Client caching

Explanation: Depth limiting controls query complexity.

Question 38: What is the role of schema stitching or federation?

Merge APIs logically
Optimize queries
Cache responses
Handle auth

Explanation: They combine multiple schemas into one graph.

Question 39: Why should GraphQL APIs be monitored?

To block clients
To detect slow queries
To increase schema size
To reduce typing

Explanation: Monitoring helps detect performance issues.

Question 40: What is the key takeaway of GraphQL at scale?

More endpoints
Flexible and strongly typed APIs
No backend logic
Automatic security

Explanation: GraphQL provides flexible yet structured APIs.

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GraphQL Quiz ( Intermediate )

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GraphQL Quiz ( Intermediate )