Unused response component (OpenAPI 3.0)

Description

components.responses stores reusable responses; a definition alone does not make it a response of any operation. Reference needed responses from the operation’s responses.

Potential impact

It may be unclear which operation returns the response, making shared response definitions harder to maintain.

Remediation

Reference the component under the actual status code. Check that its content and format match the API, and remove unnecessary definitions only after checking external document use.

Examples

These examples retain the existing 200 response and add a NotFound reference for 404.

Before

json

{
  "openapi": "3.0.0",
  "info": {
    "title": "Simple API Overview",
    "version": "1.0.0"
  },
  "paths": {
    "/": {
      "get": {
        "operationId": "listVersionsv2",
        "summary": "List API versions",
        "responses": {
          "200": {
            "description": "Success",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/MyObject"
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "Error": {
        "type": "object",
        "properties": {
          "code": {
            "type": "string"
          },
          "message": {
            "type": "string"
          }
        },
        "required": [
          "code",
          "message"
        ]
      },
      "MyObject": {
        "type": "object",
        "properties": {
          "id": {
            "type": "string"
          },
          "name": {
            "type": "string"
          }
        }
      }
    },
    "responses": {
      "NotFound": {
        "description": "Resource not found",
        "content": {
          "application/json": {
            "schema": {
              "$ref": "#/components/schemas/Error"
            }
          }
        }
      }
    }
  }
}

After