2. What is GraphQL?

What is GraphQL?

A query language that enables us to do declarative data fetching, which means:

  • We can describe the data we want,
  • Bundle it all up in one request,
  • And get data back in a predictable shape.


  • Describes the shape of the available data
  • A hierarchy of types and fields, populated by backend data stores

Entry points to the schema:

  • Queries: read operations that retrieve data
  • Mutations: write operations that update data

The journey of a GraphQL operation

Hand-drawn illustration depicting the full journey of a GraphQL query

Check your understanding

How does the client send queries to our GraphQL server?

Which of these are situations where our GraphQL server will throw an error?

When a query executes successfully, which of these is included in the object returned by the GraphQL server?