Skip to main content
POST
Submit signed message

Authorizations

x-api-key
string
header
default:NEYNAR_API_DOCS
required

API key to authorize requests

Body

application/octet-stream

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.

The body is of type file.

Response

A successful response.

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.

data
object
required

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.

hash
string
required
Pattern: ^0x[0-9a-fA-F]{40}$
Example:

"0xd2b1ddc6c88e865a33cb1a565e0058d757042974"

hashScheme
enum<string>
default:HASH_SCHEME_BLAKE3
required

Type of hashing scheme used to produce a digest of MessageData. - HASH_SCHEME_BLAKE3: Default scheme for hashing MessageData

Available options:
HASH_SCHEME_BLAKE3
signature
string<byte>
required
Pattern: ^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$
signatureScheme
enum<string>
default:SIGNATURE_SCHEME_ED25519
required

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
Available options:
SIGNATURE_SCHEME_ED25519,
SIGNATURE_SCHEME_EIP712
signer
string
required
Pattern: ^0x[0-9a-fA-F]+$