# Documentation Index Fetch the complete documentation index at: [/llms.txt](https://docs.neynar.com/llms.txt) Use this file to discover all available pages before exploring further. --- A message is the fundamental data type in the Farcaster network. When an account takes an action like casting a public message, changing its profile, or verifying an Ethereum account, it generates a new message. ## 1. Message The message is a protobuf that contains the data, its hash and a signature from the author. | Field | Type | Label | Description | |--------------------|--------------------------------------------------------------|-------|------------------------------------------------------------------------------------------------------------------------------------| | data | [MessageData](https://docs.neynar.com/snapchain/datatypes/messages#MessageData) | | Contents of the message. Alternatively, you can use the data_bytes to serialize the `MessageData` | | hash | bytes | | Hash digest of data | | hash_scheme | [HashScheme](https://docs.neynar.com/snapchain/datatypes/messages#HashScheme) | | Hash scheme that produced the hash digest | | signature | bytes | | Signature of the hash digest | | signature_scheme | [SignatureScheme](https://docs.neynar.com/snapchain/datatypes/messages#SignatureScheme) | | Signature scheme that produced the signature | | signer | bytes | | Public key or address of the key pair that produced the signature | | data_bytes | bytes | | Alternate to the “data” field. If you are constructing the [MessageData](https://docs.neynar.com/snapchain/datatypes/messages#MessageData) in a programming language other than Typescript, you can use this field to serialize the `MessageData` and calculate the `hash` and `signature` on these bytes. Optional. | ### 1.1 MessageData MessageData is a generic envelope that contains a type, fid, timestamp and network which must be present in all Farcaster messages. It also contains a body whose type is determined by the MessageType. | Field | Type | Label | Description | |--------------------|--------------------------------------------------------------|-------|------------------------------------------------------------------------------------------------------------------------------------| | type | [MessageType](https://docs.neynar.com/snapchain/datatypes/messages#MessageType) | | Type of Message contained in the body | | fid | uint64 | | Farcaster ID of the user producing the message | | timestamp | uint32 | | Farcaster epoch timestamp in seconds | | network | [FarcasterNetwork](https://docs.neynar.com/snapchain/datatypes/messages#FarcasterNetwork) | | Farcaster network the message is intended for | | body | [CastAddBody](https://docs.neynar.com/snapchain/datatypes/messages#CastAddBody), [CastRemoveBody](https://docs.neynar.com/snapchain/datatypes/messages#CastRemoveBody), [ReactionBody](https://docs.neynar.com/snapchain/datatypes/messages#ReactionBody), [VerificationAddAddressBody](https://docs.neynar.com/snapchain/datatypes/messages#VerificationAddAddressBody), [VerificationRemoveBody](https://docs.neynar.com/snapchain/datatypes/messages#VerificationRemoveBody), [UserDataBody](https://docs.neynar.com/snapchain/datatypes/messages#UserDataBody), [LinkBody](https://docs.neynar.com/snapchain/datatypes/messages#LinkBody), [UserNameProof](https://docs.neynar.com/snapchain/datatypes/messages#UserNameProof), [FrameActionBody](https://docs.neynar.com/snapchain/datatypes/messages#FrameActionBody), [LinkCompactStateBody](https://docs.neynar.com/snapchain/datatypes/messages#LinkCompactStateBody) | oneOf | Properties specific to the MessageType | ### 1.2 HashScheme Type of hashing scheme used to produce a digest of MessageData | Name | Number | Description | |-----------------------------|--------|--------------------------| | HASH_SCHEME_NONE | 0 | | | HASH_SCHEME_BLAKE3 | 1 | Default scheme for hashing MessageData | ### 1.3 Signature Scheme Type of signature scheme used to sign the Message hash | Name | Number | Description | |-----------------------------|--------|---------------------------------------------------| | SIGNATURE_SCHEME_NONE | 0 | | | SIGNATURE_SCHEME_ED25519 | 1 | Ed25519 signature (default) | | SIGNATURE_SCHEME_EIP712 | 2 | ECDSA signature using EIP-712 scheme | ### 1.4 Message Type Type of the MessageBody | Name | Number | Description | |-----------------------------------|--------|-----------------------------------| | MESSAGE_TYPE_NONE | 0 | Invalid default value | | MESSAGE_TYPE_CAST_ADD | 1 | Add a new Cast | | MESSAGE_TYPE_CAST_REMOVE | 2 | Remove an existing Cast | | MESSAGE_TYPE_REACTION_ADD | 3 | Add a Reaction to a Cast | | MESSAGE_TYPE_REACTION_REMOVE | 4 | Remove a Reaction from a Cast | | MESSAGE_TYPE_LINK_ADD | 5 | Add a Link to a target | | MESSAGE_TYPE_LINK_REMOVE | 6 | Remove a Link from a target | | MESSAGE_TYPE_VERIFICATION_ADD_ETH_ADDRESS | 7 | Add a Verification of an Address | | MESSAGE_TYPE_VERIFICATION_REMOVE | 8 | Remove a Verification | | MESSAGE_TYPE_USER_DATA_ADD | 11 | Add metadata about a user | | MESSAGE_TYPE_USERNAME_PROOF | 12 | Add or replace a username proof | | MESSAGE_TYPE_FRAME_ACTION | 13 | Frame action (not stored) | | MESSAGE_TYPE_LINK_COMPACT_STATE | 14 | Compact state for links | ### 1.5 Farcaster Network Farcaster network the message is intended for | Name | Number | Description | |-------------------------------|--------|---------------------------------| | FARCASTER_NETWORK_NONE | 0 | | | FARCASTER_NETWORK_MAINNET | 1 | Public primary network | | FARCASTER_NETWORK_TESTNET | 2 | Public test network | | FARCASTER_NETWORK_DEVNET | 3 | Private test network | ## 2. UserData A UserData message represents user metadata (e.g. a profile picture url). ### 2.1 UserDataBody Body of a UserData message | Field | Type | Label | Description | |--------------------|--------------------------------------------------------------|-------|------------------------------------------------------------------------------------------------------------------------------------| | type | [UserDataType](https://docs.neynar.com/snapchain/datatypes/messages#UserDataType) | | Type of metadata | | value | string | | Value of the metadata | ### 2.2 UserDataType Type of UserData message | Name | Number | Description | |-------------------------------|--------|--------------------------------| | USER_DATA_TYPE_NONE | 0 | Invalid default value | | USER_DATA_TYPE_PFP | 1 | Profile Picture for the user | | USER_DATA_TYPE_DISPLAY | 2 | Display Name for the user | | USER_DATA_TYPE_BIO | 3 | Bio for the user | | USER_DATA_TYPE_URL | 5 | URL of the user | | USER_DATA_TYPE_USERNAME | 6 | Preferred Farcaster Name for the user | | USER_DATA_TYPE_LOCATION | 7 | Location for the user | | USER_DATA_TYPE_TWITTER | 8 | Twitter username for the user | | USER_DATA_TYPE_GITHUB | 9 | GitHub username for the user | | USER_DATA_TYPE_BANNER | 10 | Banner image for the user | | USER_DATA_PRIMARY_ADDRESS_ETHEREUM | 11 | Primary Ethereum address | | USER_DATA_PRIMARY_ADDRESS_SOLANA | 12 | Primary Solana address | ## 3. Cast A Cast message is a public post from a user. ### 3.1 CastAddBody Adds a new Cast message. | Field | Type | Label | Description | |----------------------|--------------------------------------------------------------|-------|------------------------------------------| | embeds_deprecated | string | repeated | URLs to be embedded in the cast | | mentions | uint64 | repeated | Fids mentioned in the cast | | parent_cast_id | [CastId](https://docs.neynar.com/snapchain/datatypes/messages#CastId) | oneOf parent | Parent cast of the cast | | parent_url | string | oneOf parent | Parent URL of the cast | | text | string | | Text of the cast | | mentions_positions | uint32 | repeated | Positions of the mentions in the text | | embeds | [Embed](https://docs.neynar.com/snapchain/datatypes/messages#Embed) | repeated | URLs or cast ids to be embedded in the cast | | type | [CastType](https://docs.neynar.com/snapchain/datatypes/messages#CastType) | | Type of cast (regular, long, etc.) | #### Embed | Field | Type | Label | Description | |----------------|--------------------------------------------------------------|-------|-------------| | url | string | | | | cast_id | [CastId](https://docs.neynar.com/snapchain/datatypes/messages#CastId) | | | ### 3.2 CastRemoveBody Removes an existing Cast message. | Field | Type | Label | Description | |----------------|--------------------------------------------------------------|-------|------------------------------------------| | target_hash | bytes | | Hash of the cast to remove | ### 3.3 CastId Identifier used to look up a Cast | Field | Type | Label | Description | |----------------|--------------------------------------------------------------|-------|------------------------------------------| | fid | uint64 | | Fid of the user who created the cast | | hash | bytes | | Hash of the cast | ## 4. Reaction A Reaction message creates a relationship between an account and a cast. (e.g. like) ### 4.1 ReactionBody Adds or removes a Reaction from a Cast | Field | Type | Label | Description | |----------------|--------------------------------------------------------------|-------|------------------------------------------| | type | [ReactionType](https://docs.neynar.com/snapchain/datatypes/messages#ReactionType) | | Type of reaction | | target_cast_id | [CastId](https://docs.neynar.com/snapchain/datatypes/messages#CastId) | | CastId of the Cast to react to | | target_url | string | | URL to react to | ### 4.2 ReactionType Type of Reaction | Name | Number | Description | |--------------------------|--------|--------------------------------------------------| | REACTION_TYPE_NONE | 0 | Invalid default value | | REACTION_TYPE_LIKE | 1 | Like the target cast | | REACTION_TYPE_RECAST | 2 | Share target cast to the user’s audience | ## 5. Link A Link message creates a relationship between two users (e.g. follow) ### 5.1 LinkBody Adds or removes a Link | Field | Type | Label | Description | |--------------------|--------------------------------------------------------------|-------|------------------------------------------| | type | string | | Type of link, <= 8 characters | | displayTimestamp | uint32 | optional | User-defined timestamp that preserves original timestamp when message.data.timestamp needs to be updated for compaction | | target_fid | uint64 | | The fid the link relates to | ## 6. Verification A Verification message is a proof of ownership of something. ### 6.1 VerificationAddAddressBody Adds a bi-directional signature proving that an fid has control over an address (supports multiple protocols). | Field | Type | Label | Description | |-------------------------|--------------------------------------------------------------|-------|------------------------------------------| | address | bytes | | Address being verified | | claim_signature | bytes | | Signature produced by the user’s address | | block_hash | bytes | | Hash of the latest block when the claim was produced | | verification_type | uint32 | | Type of verification (0 = EOA, 1 = contract) | | chain_id | uint32 | | Chain ID of the verification | | protocol | [Protocol](https://docs.neynar.com/snapchain/datatypes/messages#Protocol) | | Protocol of the address (Ethereum, Solana, etc.) | ### 6.2 VerificationRemoveBody Removes a Verification of any type | Field | Type | Label | Description | |----------------|--------------------------------------------------------------|-------|------------------------------------------| | address | bytes | | Address of the Verification to remove | ## 7. Frame Action Represents an action performed by a user on a frame. This message is not stored on the nodes and cannot be submitted, only validated. ### 7.1 FrameActionBody A user action on a frame | Field | Type | Label | Description | |--------------------|--------------------------------------------------------------|-------|------------------------------------------| | url | bytes | | The original url of the frame as embedded in the cast | | button_index | uint32 | | The button that was pressed (indexed from 1) | | cast_id | [CastId](https://docs.neynar.com/snapchain/datatypes/messages#CastId) | | The cast id that hosted the frame | | input_text | bytes | | Any text the user input as part of the action | | state | bytes | | Serialized state passed from frame to server | | transaction_id | bytes | | Transaction ID for transaction frames | | address | bytes | | Address involved in the frame action | ## 8. Protocol Type of protocol for addresses | Name | Number | Description | |-------------------------------|--------|--------------------------------------| | PROTOCOL_ETHEREUM | 0 | Ethereum | | PROTOCOL_SOLANA | 1 | Solana | ## 9. CastType Type of cast | Name | Number | Description | |-------------------------------|--------|-----------------------------------------| | CAST | 0 | Regular cast | | LONG_CAST | 1 | Extended length cast | | TEN_K_CAST | 2 | Ten thousand character cast | ## 10. LinkCompactStateBody Compact state representation for links | Field | Type | Label | Description | |---------------------|-------------------------------------------------------------|-------|------------------------------------------| | type | string | | Type of link | | target_fids | uint64 | repeated | Array of target fids |