Treating errors as data

Another possible method to describe errors in GraphQL is to treat them as data. Unlike traditional REST APIs, where errors are often returned as HTTP status codes, GraphQL encourages us to model errors using GraphQL types. This approach enables clients to understand and describe errors in a more structured and predictable manner. This way, schema consumers can receive fully described expected error descriptions and simply display them to the end user.

Let’s take a look at an example. In the following schema, we created a dedicated PostError type to keep the structure of the error response inside our GraphQL schema:

type Post{
  title: String
  content: String
}
enum ErrorVariant{
  NOT_FOUND
  FORBIDDEN
}
type PostError{
  message: String!
  variant: ErrorVariant
}
type PostDescribedResponse{
  posts: [Post!]
  errors: [PostError!]
}
type Query{
  describedErrors...