> ## Documentation Index > Fetch the complete documentation index at: https://docs.neynar.com/llms.txt > Use this file to discover all available pages before exploring further. # By parent cast > 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. ## OpenAPI ````yaml get /v1/castsByParent openapi: 3.0.4 info: title: Farcaster Hub API version: 2.35.0 description: > Perform basic queries of Farcaster state via the REST API of a Farcaster hub. See the [Neynar docs](https://docs.neynar.com/reference) for more details. contact: name: Neynar url: https://neynar.com/ email: team@neynar.com servers: - url: https://snapchain-api.neynar.com security: - ApiKeyAuth: [] tags: - name: Info description: Operations related to hub information. - name: Casts description: Operations related to casts. - name: Reactions description: Operations related to reactions. - name: Links description: Operations related to links. - name: UserData description: Operations related to user data. - name: Fids description: Operations related to FIDs. - name: Storage description: Operations related to storage limits. - name: Usernames description: Operations related to usernames. - name: Verifications description: Operations related to verifications. - name: OnChainEvents description: Operations related to on-chain events. - name: Message description: Operations related to messages. - name: HubEvents description: Operations related to hub events. paths: /v1/castsByParent: get: tags: - Casts 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. operationId: fetch-casts-by-parent parameters: - name: fid in: query 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 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 description: Cast URL starting with 'chain://' schema: type: string format: uri example: chain://eip155:1/erc721:0x39d89b649ffa044383333d297e325d42d31329b2 - $ref: '#/components/parameters/pageSize' - $ref: '#/components/parameters/paginationReverse' - $ref: '#/components/parameters/pageToken' responses: '200': description: >- A successful response containing all reply casts to the specified parent cast, along with pagination information for traversing large result sets. content: application/json: 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' default: $ref: '#/components/responses/ErrorResponse' externalDocs: description: Fetch casts by parent url: https://docs.neynar.com/reference/fetch-casts-by-parent components: parameters: pageSize: name: pageSize in: query description: Maximum number of messages to return in a single response schema: type: integer paginationReverse: name: reverse in: query description: Reverse the sort order, returning latest messages first schema: type: boolean pageToken: name: pageToken in: query description: >- The page token returned by the previous query, to fetch the next page. If this parameter is empty, fetch the first page schema: type: string schemas: CastAdd: allOf: - $ref: '#/components/schemas/MessageCommon' - type: object properties: data: allOf: - $ref: '#/components/schemas/MessageDataCastAdd' - type: object properties: type: $ref: '#/components/schemas/MessageType' required: - type required: - data PaginationResponse: type: object required: - nextPageToken properties: nextPageToken: type: string format: byte pattern: ^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$ description: >- Base64-encoded pagination token for fetching the next page of results. An empty value indicates there are no more pages to return. Used in conjunction with the pageSize parameter to implement pagination across large result sets. example: AuzO1V0DtaItCwwa10X6YsfStlynsGWT MessageCommon: type: object properties: hash: title: Hash digest of data pattern: ^0x[0-9a-fA-F]{40}$ type: string example: '0xd2b1ddc6c88e865a33cb1a565e0058d757042974' hashScheme: $ref: '#/components/schemas/HashScheme' signature: title: Signature of the hash digest pattern: ^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$ type: string format: byte signatureScheme: $ref: '#/components/schemas/SignatureScheme' signer: title: Public key or address of the key pair that produced the signature pattern: ^0x[0-9a-fA-F]+$ type: string required: - hash - hashScheme - signature - signatureScheme - signer MessageDataCastAdd: description: >- Represents a new cast (post) being created in the Farcaster network. A cast can include text content, mentions of other users, embedded URLs, and references to parent posts for replies. allOf: - $ref: '#/components/schemas/MessageDataCommon' - type: object required: - castAddBody properties: castAddBody: description: >- The content and metadata of the new cast, including the text, mentions, embeds, and any parent references for replies. allOf: - $ref: '#/components/schemas/CastAddBody' MessageType: type: string description: >- Type of the MessageBody. - MESSAGE_TYPE_CAST_ADD: Add a new Cast - MESSAGE_TYPE_CAST_REMOVE: Remove an existing Cast - MESSAGE_TYPE_REACTION_ADD: Add a Reaction to a Cast - MESSAGE_TYPE_REACTION_REMOVE: Remove a Reaction from a Cast - MESSAGE_TYPE_LINK_ADD: Add a new Link - MESSAGE_TYPE_LINK_REMOVE: Remove an existing Link - MESSAGE_TYPE_VERIFICATION_ADD_ETH_ADDRESS: Add a Verification of an Ethereum Address - MESSAGE_TYPE_VERIFICATION_REMOVE: Remove a Verification - MESSAGE_TYPE_USER_DATA_ADD: Add metadata about a user - MESSAGE_TYPE_USERNAME_PROOF: Add or replace a username proof - MESSAGE_TYPE_FRAME_ACTION: A Farcaster Frame action default: MESSAGE_TYPE_CAST_ADD enum: - MESSAGE_TYPE_CAST_ADD - MESSAGE_TYPE_CAST_REMOVE - MESSAGE_TYPE_REACTION_ADD - MESSAGE_TYPE_REACTION_REMOVE - MESSAGE_TYPE_LINK_ADD - MESSAGE_TYPE_LINK_REMOVE - MESSAGE_TYPE_VERIFICATION_ADD_ETH_ADDRESS - MESSAGE_TYPE_VERIFICATION_REMOVE - MESSAGE_TYPE_USER_DATA_ADD - MESSAGE_TYPE_USERNAME_PROOF - MESSAGE_TYPE_FRAME_ACTION ErrorResponse: required: - code - details - errCode - metadata - name - presentable type: object properties: errCode: type: string presentable: type: boolean name: type: string code: type: integer details: type: string metadata: required: - errcode type: object properties: errcode: type: array items: type: string HashScheme: type: string description: > Type of hashing scheme used to produce a digest of MessageData. - HASH_SCHEME_BLAKE3: Default scheme for hashing MessageData default: HASH_SCHEME_BLAKE3 enum: - HASH_SCHEME_BLAKE3 SignatureScheme: type: string description: |- Type of signature scheme used to sign the Message hash - SIGNATURE_SCHEME_ED25519: Ed25519 signature (default) - SIGNATURE_SCHEME_EIP712: ECDSA signature using EIP-712 scheme default: SIGNATURE_SCHEME_ED25519 enum: - SIGNATURE_SCHEME_ED25519 - SIGNATURE_SCHEME_EIP712 MessageDataCommon: description: >- Common properties shared by all Farcaster message types. These properties provide essential metadata about the message's origin, timing, and network context. required: - fid - network - timestamp type: object properties: type: $ref: '#/components/schemas/MessageType' fid: title: Farcaster ID of the user producing the message description: >- The unique identifier (FID) of the user who created this message. FIDs are assigned sequentially when users register on the network and cannot be changed. type: integer format: uint64 example: 2 timestamp: description: >- Seconds since Farcaster Epoch (2021-01-01T00:00:00Z). Used to order messages chronologically and determine the most recent state. Must be within 10 minutes of the current time when the message is created. type: integer format: int64 example: 48994466 network: $ref: '#/components/schemas/FarcasterNetwork' CastAddBody: description: Adds a new Cast type: object properties: embedsDeprecated: title: URLs to be embedded in the cast type: array items: type: string mentions: title: Fids mentioned in the cast type: array items: type: integer format: uint64 example: 2 parentCastId: $ref: '#/components/schemas/CastId' parentUrl: title: Parent URL type: string example: chain://eip155:1/erc721:0x39d89b649ffa044383333d297e325d42d31329b2 text: title: Text of the cast type: string mentionsPositions: title: Positions of the mentions in the text type: array items: type: integer format: int64 embeds: title: URLs or cast IDs to be embedded in the cast type: array items: $ref: '#/components/schemas/Embed' required: - embedsDeprecated - mentions - text - mentionsPositions - embeds FarcasterNetwork: type: string description: |- Farcaster network the message is intended for. - FARCASTER_NETWORK_MAINNET: Public primary network - FARCASTER_NETWORK_TESTNET: Public test network - FARCASTER_NETWORK_DEVNET: Private test network default: FARCASTER_NETWORK_MAINNET enum: - FARCASTER_NETWORK_MAINNET - FARCASTER_NETWORK_TESTNET - FARCASTER_NETWORK_DEVNET CastId: description: >- A unique identifier for a cast (post) in the Farcaster network, consisting of the creator's FID and a hash of the cast's content. This combination ensures global uniqueness across all casts. required: - fid - hash type: object properties: fid: title: Fid of the user who created the cast description: >- The Farcaster ID (FID) of the user who created the cast. Required to uniquely identify the cast's author in the network. type: integer format: uint64 example: 2 hash: $ref: '#/components/schemas/CastHash' Embed: oneOf: - $ref: '#/components/schemas/CastEmbed' - $ref: '#/components/schemas/UrlEmbed' CastHash: description: >- A unique hash that identifies a specific cast within the creator's posts. Generated using HASH_SCHEME_BLAKE3 of the cast's content. pattern: ^0x[0-9a-fA-F]{40}$ type: string example: '0x03aff391a6eb1772b20b4ead9a89f732be75fe27' CastEmbed: type: object properties: castId: $ref: '#/components/schemas/CastId' required: - castId UrlEmbed: type: object properties: url: type: string format: uri required: - url responses: ErrorResponse: description: An unexpected error response. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' securitySchemes: ApiKeyAuth: type: apiKey in: header name: x-api-key description: API key to authorize requests x-default: NEYNAR_API_DOCS ````