{
  "operationId": "hub-fetch-casts-by-parent",
  "method": "GET",
  "path": "/v1/castsByParent",
  "summary": "By parent cast",
  "description": "Retrieve all reply casts (responses) to a specific parent cast in the Farcaster network. Parent casts can be identified using either a combination of FID and hash, or by their URL. This endpoint enables traversal of conversation threads and retrieval of all responses to a particular cast.",
  "tags": [
    "Casts"
  ],
  "parameters": [
    {
      "name": "fid",
      "in": "query",
      "required": false,
      "description": "The Farcaster ID (FID) of the parent cast's creator. This parameter must be used together with the 'hash' parameter to uniquely identify a parent cast. Required only when using hash-based lookup instead of URL-based lookup. The FID is a unique identifier assigned to each Farcaster user.",
      "schema": {
        "type": "integer",
        "format": "uint64",
        "minimum": 1,
        "example": 194
      }
    },
    {
      "name": "hash",
      "in": "query",
      "required": false,
      "description": "The unique hash identifier of the parent cast. Must be used together with the 'fid' parameter when doing hash-based lookup. This is a 40-character hexadecimal string prefixed with '0x' that uniquely identifies the cast within the creator's posts. Not required if using URL-based lookup.",
      "schema": {
        "type": "string",
        "pattern": "^0x[0-9a-fA-F]{40}$",
        "example": "0x776593353e47dc4e7f4df3199a9b04cc8efa30d9"
      }
    },
    {
      "name": "url",
      "in": "query",
      "required": false,
      "description": "Cast URL starting with 'chain://'",
      "schema": {
        "type": "string",
        "format": "uri",
        "example": "chain://eip155:1/erc721:0x39d89b649ffa044383333d297e325d42d31329b2"
      }
    },
    {
      "name": "",
      "in": "",
      "required": false,
      "description": ""
    },
    {
      "name": "",
      "in": "",
      "required": false,
      "description": ""
    },
    {
      "name": "",
      "in": "",
      "required": false,
      "description": ""
    }
  ],
  "requestBody": null,
  "responses": {
    "200": {
      "description": "A successful response containing all reply casts to the specified parent cast, along with pagination information for traversing large result sets.",
      "schema": {
        "allOf": [
          {
            "type": "object",
            "required": [
              "messages"
            ],
            "properties": {
              "messages": {
                "description": "An array of reply casts to the specified parent cast, ordered by oldest first. Each cast includes its content, timestamp, and other metadata.",
                "type": "array",
                "items": {
                  "$ref": "#/components/schemas/CastAdd"
                }
              }
            }
          },
          {
            "$ref": "#/components/schemas/PaginationResponse"
          }
        ]
      },
      "example": null
    }
  }
}