Change server-side data through clearly defined operations instead of treating every request like a simple read.
Queries are mainly used to read data, while mutations are used when the client needs to change data on the server. Creating a user, updating a product, or deleting a comment can each be represented as a mutation with clearly defined inputs and outputs.
A mutation can accept structured input and return the data that changed. Designing mutations carefully makes the API predictable and helps clients update their local state after an operation completes.
What you'll walk away knowing