juniorGraphQL
What is a Mutation in GraphQL?
Updated Apr 28, 2026
Short answer
A Mutation is an operation used to create, update, or delete data on the server.
Deep explanation
Unlike Queries, top-level Mutation fields run serially (one after another) to prevent race conditions during write operations. A mutation usually returns the modified object, allowing the client to update its local state immediately.
Real-world example
Submitting a 'Sign Up' form to create a new user account.
Common mistakes
- Not returning the modified data from a mutation, forcing the client to make a separate query to get the updated state.
Follow-up questions
- Why do mutations execute serially?