> ## 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. # Validate signed message > Validate a message on the Farcaster network. ## OpenAPI ````yaml post /v1/validateMessage 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/validateMessage: post: tags: - Message summary: Validate signed message description: Validate a message on the Farcaster network. operationId: validate-message requestBody: description: > A Message is a delta operation on the Farcaster network. The message protobuf is an envelope that wraps a MessageData object and contains a hash and signature which can verify its authenticity. content: application/octet-stream: schema: type: string format: binary required: true responses: '200': description: A successful response. content: application/json: schema: $ref: '#/components/schemas/ValidateMessageResponse' default: $ref: '#/components/responses/ErrorResponse' externalDocs: description: Validate a message on the Farcaster network url: https://docs.neynar.com/reference/validate-message components: schemas: ValidateMessageResponse: type: object properties: valid: type: boolean message: $ref: '#/components/schemas/Message' required: - valid - message Message: allOf: - type: object properties: data: oneOf: - $ref: '#/components/schemas/MessageDataCastAdd' - $ref: '#/components/schemas/MessageDataCastRemove' - $ref: '#/components/schemas/MessageDataReaction' - $ref: '#/components/schemas/MessageDataLink' - $ref: '#/components/schemas/MessageDataVerificationAdd' - $ref: '#/components/schemas/MessageDataVerificationRemove' - $ref: '#/components/schemas/MessageDataUserDataAdd' - $ref: '#/components/schemas/MessageDataUsernameProof' - $ref: '#/components/schemas/MessageDataFrameAction' discriminator: propertyName: type mapping: MESSAGE_TYPE_CAST_ADD: $ref: '#/components/schemas/MessageDataCastAdd' MESSAGE_TYPE_CAST_REMOVE: $ref: '#/components/schemas/MessageDataCastRemove' MESSAGE_TYPE_REACTION_ADD: $ref: '#/components/schemas/MessageDataReaction' MESSAGE_TYPE_REACTION_REMOVE: $ref: '#/components/schemas/MessageDataReaction' MESSAGE_TYPE_LINK_ADD: $ref: '#/components/schemas/MessageDataLink' MESSAGE_TYPE_LINK_REMOVE: $ref: '#/components/schemas/MessageDataLink' MESSAGE_TYPE_VERIFICATION_ADD_ETH_ADDRESS: $ref: '#/components/schemas/MessageDataVerificationAdd' MESSAGE_TYPE_VERIFICATION_REMOVE: $ref: '#/components/schemas/MessageDataVerificationRemove' MESSAGE_TYPE_USER_DATA_ADD: $ref: '#/components/schemas/MessageDataUserDataAdd' MESSAGE_TYPE_USERNAME_PROOF: $ref: '#/components/schemas/MessageDataUsernameProof' MESSAGE_TYPE_FRAME_ACTION: $ref: '#/components/schemas/MessageDataFrameAction' required: - data - $ref: '#/components/schemas/MessageCommon' description: >- A Message is a delta operation on the Farcaster network that represents a state change. Messages are the fundamental unit of data in Farcaster and can represent various actions like: - Creating or removing casts (posts) - Adding or removing reactions - Following or unfollowing users - Updating profile data - Verifying Ethereum addresses Each message contains: - A MessageData object with the actual content - A hash of the content for integrity verification - A cryptographic signature to prove authenticity - The signer's public key for verification Messages are immutable once created and form an append-only log of all user actions on the network. 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 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' MessageDataCastRemove: description: >- Represents a request to remove (delete) a previously created cast. Only the original creator of a cast can remove it. allOf: - $ref: '#/components/schemas/MessageDataCommon' - type: object required: - targetHash properties: targetHash: title: Hash of the cast to remove description: >- The unique hash identifier of the cast to be removed. Must be a cast that was previously created by the same FID specified in the message. pattern: ^0x[0-9a-fA-F]{40}$ type: string example: '0x03aff391a6eb1772b20b4ead9a89f732be75fe27' MessageDataReaction: description: >- Represents a user's reaction to content on the Farcaster network. Reactions can be likes or recasts of casts, allowing users to express appreciation or share content with their followers. allOf: - $ref: '#/components/schemas/MessageDataCommon' - type: object required: - reactionBody properties: reactionBody: description: >- Contains the type of reaction (like/recast) and the target content being reacted to. The target can be specified either by castId or URL. allOf: - $ref: '#/components/schemas/ReactionBody' MessageDataLink: description: >- Represents a social graph connection between users in the Farcaster network. Currently supports following relationships between users. allOf: - $ref: '#/components/schemas/MessageDataCommon' - type: object required: - linkBody properties: linkBody: description: >- Contains the details of the social connection, including the type of relationship and the target user. allOf: - $ref: '#/components/schemas/LinkBody' MessageDataVerificationAdd: description: >- Represents a message that adds verification of ownership for an Ethereum or Solana address to a user's profile. This verification proves that the user controls the specified blockchain address. allOf: - $ref: '#/components/schemas/MessageDataCommon' - type: object required: - verificationAddEthAddressBody properties: verificationAddEthAddressBody: description: >- Contains the blockchain address being verified, along with cryptographic proof of ownership through a signature. allOf: - $ref: '#/components/schemas/VerificationAddEthAddressBody' MessageDataVerificationRemove: description: >- Represents a message that removes an existing blockchain address verification from a user's profile. This allows users to disassociate previously verified addresses from their account. allOf: - $ref: '#/components/schemas/MessageDataCommon' - type: object required: - verificationRemoveBody properties: verificationRemoveBody: description: >- Contains the blockchain address for which the verification should be removed from the user's profile. allOf: - $ref: '#/components/schemas/VerificationRemoveBody' MessageDataUserDataAdd: description: >- Represents a message that updates a user's profile metadata. This can include changes to profile picture, display name, bio, URL, or preferred username. Each update modifies a single profile field. allOf: - $ref: '#/components/schemas/MessageDataCommon' - type: object required: - userDataBody properties: userDataBody: description: >- Contains the type of profile metadata being updated and its new value. allOf: - $ref: '#/components/schemas/UserDataBody' MessageDataUsernameProof: allOf: - $ref: '#/components/schemas/MessageDataCommon' - type: object required: - usernameProofBody properties: usernameProofBody: $ref: '#/components/schemas/UserNameProof' MessageDataFrameAction: description: >- Represents a user's interaction with a Farcaster Frame, which is an interactive element embedded within a cast. Frames allow users to engage with content through clickable buttons, creating interactive experiences within the Farcaster network. allOf: - $ref: '#/components/schemas/MessageDataCommon' - type: object required: - frameActionBody properties: frameActionBody: description: >- Contains the details of the frame interaction, including which button was pressed and the associated cast and URL. allOf: - $ref: '#/components/schemas/FrameActionBody' MessageCommon: type: object properties: hash: title: Hash digest of data pattern: ^0x[0-9a-fA-F]{40}$ 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 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 ReactionBody: description: >- Specifies the details of a reaction to content on Farcaster. A reaction must specify its type (like/recast) and either a target cast ID or URL to react to. Only one target (either castId or URL) should be specified per reaction. type: object properties: type: $ref: '#/components/schemas/ReactionType' targetCastId: description: >- The unique identifier of the cast being reacted to. Must be a valid CastId containing the creator's FID and the cast's hash. allOf: - $ref: '#/components/schemas/CastId' targetUrl: title: URL to react to description: >- The URL being reacted to. Used when reacting to external content or when the cast ID is not available. type: string example: https://www.example.com/article required: - type LinkBody: description: >- Defines a social connection between users in the Farcaster network. Currently used to establish following relationships, allowing users to curate their content feed. type: object properties: type: $ref: '#/components/schemas/LinkType' displayTimestamp: title: Original Timestamp description: >- User-defined timestamp that preserves the original creation time when message.data.timestamp needs to be updated for compaction. Useful for maintaining chronological order in user feeds. type: integer format: int64 example: 48994466 targetFid: $ref: '#/components/schemas/FidSchema' required: - type - targetFid VerificationAddEthAddressBody: description: >- Contains the data required to verify ownership of an Ethereum or Solana address. The verification process requires a cryptographic signature from the blockchain address and includes the block hash at the time of signing for timestamp verification. type: object properties: address: title: Blockchain Address description: >- The Ethereum (0x-prefixed) or Solana address that the user is claiming ownership of. Must match the address that produced the signature. pattern: ^(?:0x[a-fA-F0-9]{40}|[1-9A-HJ-NP-Za-km-z]{32,44})$ type: string example: '0x1234567890123456789012345678901234567890' ethSignature: title: Cryptographic Signature description: >- Base64-encoded signature produced by the blockchain address, proving ownership. For Ethereum, this is an ECDSA signature of a specific message format. pattern: ^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$ type: string format: byte example: >- 4mGN6TACFqXUVU9RpwLDGCqgqiV1GidEFk9eKF0L0h6JNqmN3kRM9NMPnjUnkh8oL6+jFeQJ9YVuKX4F9EqGiAE= blockHash: title: Block Hash description: >- The hash of the most recent block when the signature was created. Used to verify the approximate time of signature creation. pattern: ^(0x[a-fA-F0-9]{64}|[1-9A-HJ-NP-Za-km-z]{44})$ type: string example: '0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef' required: - address - ethSignature - blockHash VerificationRemoveBody: description: >- Contains the data required to remove a previously added blockchain address verification from a user's profile. This operation permanently removes the verification until explicitly re-added. type: object properties: address: title: Blockchain Address description: >- The Ethereum address (0x-prefixed) for which the verification should be removed. Must match a previously verified address in the user's profile. pattern: ^0x[A-Za-z0-9]{40}$ type: string example: '0x1234567890123456789012345678901234567890' required: - address UserDataBody: description: >- Contains the data for updating a specific field of a user's profile metadata. Each update operation modifies one profile field at a time, allowing granular control over profile information. type: object properties: type: description: >- Specifies which profile field is being updated (e.g., profile picture, display name, bio). allOf: - $ref: '#/components/schemas/UserDataType' value: title: Profile Field Value description: >- The new value for the specified profile field. The format depends on the type: URLs for profile pictures, plain text for display names and bios, etc. type: string example: https://i.imgur.com/123abc.jpg required: - type - value UserNameProof: type: object properties: timestamp: description: Seconds since Unix Epoch which began on Jan 1, 1970 00:00:00 UTC type: integer format: uint64 name: type: string example: neynar owner: pattern: ^0x[0-9a-fA-F]{40}$ type: string signature: pattern: ^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$ type: string format: byte fid: description: The FID of the user who owns this username proof allOf: - $ref: '#/components/schemas/FidSchema' type: $ref: '#/components/schemas/UserNameType' required: - timestamp - name - owner - signature - fid - type FrameActionBody: description: >- Contains the data for a user's interaction with a Farcaster Frame. Frames are interactive elements within casts that can have up to 4 clickable buttons, allowing users to engage with content in predefined ways. type: object properties: url: description: >- The URL associated with the frame action. This typically points to the frame's content or the destination that handles the interaction. type: string format: uri example: https://frames.farcaster.xyz/frame/123 buttonIndex: description: >- Identifies which button the user clicked in the frame. Frames can have up to 4 buttons, numbered from 1 to 4. title: Button Index type: integer format: int32 minimum: 1 maximum: 4 example: 1 castId: description: >- The unique identifier of the cast containing the frame that was interacted with. allOf: - $ref: '#/components/schemas/CastId' required: - url - buttonIndex - castId 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 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 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' - $ref: '#/components/schemas/UrlEmbed' ReactionType: type: string description: >- Type of interaction a user can have with content on the Farcaster network. - Like: Express appreciation for the target content. Similar to "likes" or "favorites" on other platforms. - Recast: Share the target content with the user's followers, similar to a "retweet" or "reblog". Helps increase content visibility. default: Like enum: - Like - Recast example: Like LinkType: type: string description: >- Defines the type of social connection between users. - follow: Establishes a following relationship where the user will receive updates from the target user in their feed default: follow enum: - follow example: follow FidSchema: type: integer format: uint64 minimum: 1 description: > Farcaster ID (FID). A unique identifier assigned to each user in the Farcaster network. This number is permanent and cannot be changed. FIDs are assigned sequentially when users register on the network. example: 1 UserDataType: type: string description: |- Specifies which field of a user's profile is being updated. - USER_DATA_TYPE_PFP: Profile Picture URL for the user's avatar - USER_DATA_TYPE_DISPLAY: Display Name shown on the user's profile - USER_DATA_TYPE_BIO: Biography or description of the user - USER_DATA_TYPE_URL: Website or social media link for the user - USER_DATA_TYPE_USERNAME: Preferred username for the user default: USER_DATA_TYPE_PFP enum: - USER_DATA_TYPE_PFP - USER_DATA_TYPE_DISPLAY - USER_DATA_TYPE_BIO - USER_DATA_TYPE_URL - USER_DATA_TYPE_USERNAME UserNameType: type: string default: USERNAME_TYPE_FNAME enum: - USERNAME_TYPE_FNAME - USERNAME_TYPE_ENS_L1 CastHash: description: >- A unique hash that identifies a specific cast within the creator's posts. Generated using HASH_SCHEME_BLAKE3 of the cast's content. pattern: ^0x[0-9a-fA-F]{40}$ 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 ````