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Top 50 GraphQL Interview Questions & Answers (2026)

50 Questions 20 Beginner 20 Intermediate 10 Advanced

About GraphQL

Top 50 GraphQL interview questions covering queries, mutations, subscriptions, schema design, and real-world GraphQL API development. Companies hiring for GraphQL roles test this knowledge at every stage — from first-round screens that check the basics to final-round conversations about real-world trade-offs.

What to Expect in a GraphQL Interview

Expect a mix of conceptual and practical GraphQL questions: clear definitions and core-concept checks for junior roles, hands-on scenario questions for mid-level roles, and architecture or trade-off discussions for senior roles. Interviewers usually move from foundational topics toward the kind of problems you'd actually face on the job.

How to Use This Guide

Work through the GraphQL questions in order — Beginner, then Intermediate, then Advanced — so each concept builds on the last. Every question has its own page; bookmark the ones that trip you up and revisit them the day before your interview.

Curated by Tech Baithak Editorial Team · Last updated: May 2026

Beginner 20 questions

Core concepts every GraphQL developer must know.

01 What is GraphQL and who created it? 02 What is the difference between GraphQL and REST? 03 What is a GraphQL query? 04 What is a GraphQL mutation? 05 What is a GraphQL subscription? 06 What is the GraphQL Schema Definition Language (SDL)? 07 What are the scalar types in GraphQL? 08 What is an object type in GraphQL? 09 What is a resolver function in GraphQL? 10 What are variables in GraphQL queries? 11 What are arguments in GraphQL? 12 What are fragments in GraphQL? 13 What are inline fragments in GraphQL? 14 What are directives in GraphQL? 15 What is an operation name in GraphQL? 16 What are aliases in GraphQL? 17 What are the three root types in GraphQL? 18 What is the difference between nullable and non-null types in GraphQL? 19 What is the GraphQL Playground and introspection? 20 What is over-fetching and under-fetching in REST and how does GraphQL solve them?

Intermediate 20 questions

Practical knowledge for developers with hands-on experience.

01 What is the N+1 problem in GraphQL and how does DataLoader solve it? 02 What are persisted queries in GraphQL? 03 What is the difference between schema-first and code-first GraphQL approaches? 04 What are the pagination strategies in GraphQL? 05 How is authentication handled in GraphQL? 06 How do you implement field-level authorization in GraphQL? 07 What are custom scalars in GraphQL? 08 What is the difference between Input types and Object types in GraphQL mutations? 09 How does error handling work in GraphQL? 10 What is the difference between union types and interface types in GraphQL? 11 What is schema stitching versus Apollo Federation in GraphQL? 12 How do GraphQL subscriptions work over WebSocket? 13 What is query depth limiting in GraphQL? 14 What is query complexity analysis in GraphQL? 15 What is Apollo Client and how does it work with GraphQL? 16 What is graphql-tag and DocumentNode? 17 How do field resolvers work with the parent object in GraphQL? 18 What are schema extensions in GraphQL? 19 What is batch loading in GraphQL and how does it improve performance? 20 What are GraphQL enums?

Advanced 10 questions

Deep expertise questions for senior and lead roles.

01 What is Apollo Federation and how do subgraphs, gateways, and directives like @key and @extends work? 02 What is incremental delivery in GraphQL with @defer and @stream? 03 How do you implement query cost analysis and rate limiting in a production GraphQL API? 04 What is schema evolution and deprecation strategy in GraphQL? 05 What is the Relay specification for GraphQL — Node interface, Connection/Edge pagination? 06 How do you implement distributed tracing across GraphQL resolvers? 07 How does client-side caching work with Apollo Client's normalized cache? 08 How do you scale GraphQL subscriptions using Redis pub/sub? 09 What is schema composition and conflict detection in Apollo Federation? 10 What is a schema registry and GraphQL governance at scale?

Back to All Topics 50 questions total