HTTP status codes are typically used for REST APIs, which are based on HTTP protocols. In the case of GraphQL, which is transport agnostic, using HTTP status codes for errors doesn’t always make sense. For more details on this, you can refer to this answer.

Regarding your specific question about Strawberry and FastAPI, instead of relying on HTTP status codes, you can return proper error responses within the GraphQL specification. The extensions attribute in GraphQL allows you to include custom error codes in the response object.
Please refer this answer.

Here’s a sample GraphQL implementation using Strawberry:

import strawberry
from graphql import GraphQLError
from typing import Optional

@strawberry.type
class Dummy:
    id: Optional[str] = None

@strawberry.type
class Query:
    @strawberry.field
    async def dummyQuery(self, info, id: strawberry.ID) -> Optional[Dummy]:
        if id == 'Error':
            raise GraphQLError(
                "Authorization failed",
                extensions={"error_code": "405"}
            )
        return Dummy(id="Valid response")

Now, if you make the following GraphQL request in GraphiQL, which includes two queries:

{
  firstQuery: dummyQuery(id: "hello") {
    ... on Dummy {
      id
    }
  }
  secondQuery: dummyQuery(id: "Error") {
    ... on Dummy {
      id
    }
  }
}

You will get this response, where one query returns an error object while the other returns a proper response:

{
  "data": {
    "firstQuery": {
      "id": "Valid response"
    },
    "secondQuery": null
  },
  "errors": [
    {
      "message": "Authorization failed",
      "locations": [
        {
          "line": 7,
          "column": 3
        }
      ],
      "path": [
        "secondQuery"
      ],
      "extensions": {
        "error_code": "405"
      }
    }
  ]
}

This approach follows GraphQL standards. However, if you absolutely need to return a specific HTTP status code, you can achieve this by modifying the response object within the resolver using info.context:

@strawberry.type
class Query:
    @strawberry.field
    async def dummyQuery(self, info, id: ID) -> Optional[Dummy]:
        if id == 'Error':
            info.context["response"].status_code = 403
            raise GraphQLError("Authorization failed", extensions={"error_code": "405"})
        return Dummy(id="Valid response")

This allows you to set a custom HTTP status code (e.g., 403) alongside the GraphQL error response.