> ## 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. # Messages > The fundamental data type in the Farcaster network - messages represent actions like casts, reactions, and verifications 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](#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](#HashScheme) | | Hash scheme that produced the hash digest | | signature | bytes | | Signature of the hash digest | | signature\_scheme | [SignatureScheme](#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](#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](#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](#FarcasterNetwork) | | Farcaster network the message is intended for | | body | [CastAddBody](#CastAddBody), [CastRemoveBody](#CastRemoveBody), [ReactionBody](#ReactionBody), [VerificationAddAddressBody](#VerificationAddAddressBody), [VerificationRemoveBody](#VerificationRemoveBody), [UserDataBody](#UserDataBody), [LinkBody](#LinkBody), [UserNameProof](#UserNameProof), [FrameActionBody](#FrameActionBody), [LinkCompactStateBody](#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](#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 | See [FIP-196](https://github.com/farcasterxyz/protocol/discussions/196) for more information on Location. See [FIP-19](https://github.com/farcasterxyz/protocol/discussions/199) for more information on Twitter/X and GitHub usernames. ## 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](#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](#Embed) | repeated | URLs or cast ids to be embedded in the cast | | type | [CastType](#CastType) | | Type of cast (regular, long, etc.) | #### Embed | Field | Type | Label | Description | | -------- | ----------------- | ----- | ----------- | | url | string | | | | cast\_id | [CastId](#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](#ReactionType) | | Type of reaction | | target\_cast\_id | [CastId](#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](#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](#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 |