diff --git a/lib/types/tunnelbroker/farcaster-messages-types.js b/lib/types/tunnelbroker/farcaster-messages-types.js
new file mode 100644
--- /dev/null
+++ b/lib/types/tunnelbroker/farcaster-messages-types.js
@@ -0,0 +1,96 @@
+// @flow
+
+import type { TInterface } from 'tcomb';
+import t from 'tcomb';
+
+import { tShape, tString } from '../../utils/validation-utils.js';
+
+type APIMethod = { +type: 'GET' } | { +type: 'PUT' } | { +type: 'STREAM' };
+
+export type FarcasterAPIRequest = {
+  +type: 'FarcasterAPIRequest',
+  +requestID: string,
+  +userID: string,
+  +apiVersion: string,
+  +endpoint: string,
+  +method: APIMethod,
+  +payload: string,
+};
+
+type FarcasterAPIResponseError = {
+  +type: 'FarcasterAPIResponseError',
+  +status: number,
+  +message: string,
+};
+export const farcasterAPIResponseErrorValidator: TInterface<FarcasterAPIResponseError> =
+  tShape<FarcasterAPIResponseError>({
+    type: tString('FarcasterAPIResponseError'),
+    status: t.Number,
+    message: t.String,
+  });
+
+type FarcasterAPIResponseDataSuccess = { +type: 'Success', +data: string };
+type FarcasterAPIResponseDataErrorResponse = {
+  +type: 'ErrorResponse',
+  +data: FarcasterAPIResponseError,
+};
+type FarcasterAPIResponseDataError = { +type: 'Error', +data: string };
+type FarcasterAPIResponseDataInvalidRequest = { +type: 'InvalidRequest' };
+type FarcasterAPIResponseDataUnauthenticated = { +type: 'Unauthenticated' };
+type FarcasterAPIResponseDataSerializationError = {
+  +type: 'SerializationError',
+  +data: string,
+};
+type FarcasterAPIResponseDataMissingFarcasterDCsToken = {
+  +type: 'MissingFarcasterDCsToken',
+};
+
+export type FarcasterAPIResponseData =
+  | FarcasterAPIResponseDataSuccess
+  | FarcasterAPIResponseDataErrorResponse
+  | FarcasterAPIResponseDataError
+  | FarcasterAPIResponseDataInvalidRequest
+  | FarcasterAPIResponseDataUnauthenticated
+  | FarcasterAPIResponseDataSerializationError
+  | FarcasterAPIResponseDataMissingFarcasterDCsToken;
+
+const farcasterAPIResponseDataValidator = t.union([
+  tShape<FarcasterAPIResponseDataSuccess>({
+    type: tString('Success'),
+    data: t.String,
+  }),
+  tShape<FarcasterAPIResponseDataErrorResponse>({
+    type: tString('ErrorResponse'),
+    data: farcasterAPIResponseErrorValidator,
+  }),
+  tShape<FarcasterAPIResponseDataError>({
+    type: tString('Error'),
+    data: t.String,
+  }),
+  tShape<FarcasterAPIResponseDataInvalidRequest>({
+    type: tString('InvalidRequest'),
+  }),
+  tShape<FarcasterAPIResponseDataUnauthenticated>({
+    type: tString('Unauthenticated'),
+  }),
+  tShape<FarcasterAPIResponseDataSerializationError>({
+    type: tString('SerializationError'),
+    data: t.String,
+  }),
+  tShape<FarcasterAPIResponseDataMissingFarcasterDCsToken>({
+    type: tString('MissingFarcasterDCsToken'),
+  }),
+]);
+
+export type FarcasterAPIResponse = {
+  +type: 'FarcasterAPIResponse',
+  +requestID: string,
+  +response: FarcasterAPIResponseData,
+};
+
+export const farcasterAPIResponseValidator: TInterface<FarcasterAPIResponse> =
+  tShape<FarcasterAPIResponse>({
+    type: tString('FarcasterAPIResponse'),
+    requestID: t.String,
+    response: farcasterAPIResponseDataValidator,
+  });
diff --git a/lib/types/tunnelbroker/messages.js b/lib/types/tunnelbroker/messages.js
--- a/lib/types/tunnelbroker/messages.js
+++ b/lib/types/tunnelbroker/messages.js
@@ -7,6 +7,11 @@
   messageToDeviceRequestStatusValidator,
   type DeviceToTunnelbrokerRequestStatus,
 } from './device-to-tunnelbroker-request-status-types.js';
+import { farcasterAPIResponseValidator } from './farcaster-messages-types.js';
+import type {
+  FarcasterAPIRequest,
+  FarcasterAPIResponse,
+} from './farcaster-messages-types.js';
 import { type MessageReceiveConfirmation } from './message-receive-confirmation-types.js';
 import { type MessageToDeviceRequest } from './message-to-device-request-types.js';
 import {
@@ -50,6 +55,7 @@
   MESSAGE_TO_DEVICE_REQUEST: 'MessageToDeviceRequest',
   MESSAGE_RECEIVE_CONFIRMATION: 'MessageReceiveConfirmation',
   MESSAGE_TO_TUNNELBROKER_REQUEST: 'MessageToTunnelbrokerRequest',
+  FARCASTER_API_REQUEST: 'FarcasterAPIRequest',
   HEARTBEAT: 'Heartbeat',
 });
 
@@ -60,22 +66,25 @@
   | MessageToDeviceRequest
   | MessageReceiveConfirmation
   | MessageToTunnelbrokerRequest
+  | FarcasterAPIRequest
   | Heartbeat;
 
-// Types having `clientMessageID` prop.
+// Types having `clientMessageID` or `requestID` prop.
 // When using this type, it is possible to use Promise abstraction,
 // and await sending a message until Tunnelbroker responds that
 // the request was processed.
 export type DeviceToTunnelbrokerRequest =
   | TunnelbrokerNotif
   | MessageToDeviceRequest
-  | MessageToTunnelbrokerRequest;
+  | MessageToTunnelbrokerRequest
+  | FarcasterAPIRequest;
 
 // Messages sent from Tunnelbroker to Device.
 export const tunnelbrokerToDeviceMessageTypes = Object.freeze({
   CONNECTION_INITIALIZATION_RESPONSE: 'ConnectionInitializationResponse',
   DEVICE_TO_TUNNELBROKER_REQUEST_STATUS: 'MessageToDeviceRequestStatus',
   MESSAGE_TO_DEVICE: 'MessageToDevice',
+  FARCASTER_API_RESPONSE: 'FarcasterAPIResponse',
   HEARTBEAT: 'Heartbeat',
 });
 
@@ -83,6 +92,7 @@
   | ConnectionInitializationResponse
   | DeviceToTunnelbrokerRequestStatus
   | MessageToDevice
+  | FarcasterAPIResponse
   | Heartbeat;
 
 export const tunnelbrokerToDeviceMessageValidator: TUnion<TunnelbrokerToDeviceMessage> =
@@ -90,5 +100,6 @@
     connectionInitializationResponseValidator,
     messageToDeviceRequestStatusValidator,
     messageToDeviceValidator,
+    farcasterAPIResponseValidator,
     heartbeatValidator,
   ]);
diff --git a/services/tunnelbroker/src/farcaster/mod.rs b/services/tunnelbroker/src/farcaster/mod.rs
--- a/services/tunnelbroker/src/farcaster/mod.rs
+++ b/services/tunnelbroker/src/farcaster/mod.rs
@@ -3,25 +3,9 @@
 use crate::farcaster::error::Error::MissingFarcasterToken;
 use reqwest::header::{HeaderMap, HeaderValue, AUTHORIZATION};
 use tracing::{debug, error};
-pub mod error;
-
-#[derive(Debug)]
-pub enum APIMethod {
-  PUT,
-  GET,
-  STREAM,
-}
+use tunnelbroker_messages::farcaster::{APIMethod, FarcasterAPIRequest};
 
-pub struct FarcasterAPIRequest {
-  pub request_id: String,
-  pub user_id: String,
-  /// API version, examples: "v2", "fc"
-  pub api_version: String,
-  pub endpoint: String,
-  pub method: APIMethod,
-  /// query, body, or stream message
-  pub payload: String,
-}
+pub mod error;
 
 #[derive(Clone)]
 pub struct FarcasterClient {
diff --git a/shared/tunnelbroker_messages/src/messages/farcaster.rs b/shared/tunnelbroker_messages/src/messages/farcaster.rs
new file mode 100644
--- /dev/null
+++ b/shared/tunnelbroker_messages/src/messages/farcaster.rs
@@ -0,0 +1,61 @@
+use serde::{Deserialize, Serialize};
+use util_macros::TagAwareDeserialize;
+
+#[derive(Serialize, Deserialize, PartialEq, Debug)]
+#[serde(tag = "type")]
+pub enum APIMethod {
+  PUT,
+  GET,
+  STREAM,
+}
+
+#[derive(Serialize, Deserialize, TagAwareDeserialize, PartialEq, Debug)]
+#[serde(tag = "type", remote = "Self", rename_all = "camelCase")]
+pub struct FarcasterAPIRequest {
+  #[serde(rename = "requestID")]
+  pub request_id: String,
+  #[serde(rename = "userID")]
+  pub user_id: String,
+  /// API version, examples: "v2", "fc"
+  #[serde(rename = "apiVersion")]
+  pub api_version: String,
+  pub endpoint: String,
+  pub method: APIMethod,
+  /// query, body, or stream message
+  pub payload: String,
+}
+
+#[derive(Serialize, Deserialize, TagAwareDeserialize, PartialEq, Debug)]
+#[serde(tag = "type", remote = "Self", rename_all = "camelCase")]
+pub struct FarcasterAPIResponseError {
+  pub status: u32,
+  pub message: String,
+}
+
+#[derive(Serialize, PartialEq, Debug)]
+#[serde(tag = "type", content = "data")]
+pub enum FarcasterAPIResponseData {
+  /// JSON stringified response
+  Success(String),
+  /// ErrorMessage
+  ErrorResponse(FarcasterAPIResponseError),
+  Error(String),
+  /// The request was invalid (e.g., Bytes instead of Text).
+  /// In this case, the request ID cannot be retrieved.
+  InvalidRequest,
+  /// Unauthenticated client tried to send a message.
+  Unauthenticated,
+  /// The JSON could not be serialized, which is why the entire request is
+  /// returned back.
+  /// It becomes impossible to retrieve the request ID in such circumstances.
+  SerializationError(String),
+  MissingFarcasterDCsToken,
+}
+
+#[derive(Serialize, TagAwareDeserialize, PartialEq, Debug)]
+#[serde(tag = "type", remote = "Self", rename_all = "camelCase")]
+pub struct FarcasterAPIResponse {
+  #[serde(rename = "requestID")]
+  pub request_id: String,
+  pub response: FarcasterAPIResponseData,
+}
diff --git a/shared/tunnelbroker_messages/src/messages/mod.rs b/shared/tunnelbroker_messages/src/messages/mod.rs
--- a/shared/tunnelbroker_messages/src/messages/mod.rs
+++ b/shared/tunnelbroker_messages/src/messages/mod.rs
@@ -2,6 +2,7 @@
 
 pub mod bad_device_token;
 pub mod device_list_updated;
+pub mod farcaster;
 pub mod keys;
 pub mod message_receive_confirmation;
 pub mod message_to_device;
@@ -26,6 +27,7 @@
 };
 
 use crate::bad_device_token::BadDeviceToken;
+use crate::messages::farcaster::{FarcasterAPIRequest, FarcasterAPIResponse};
 use crate::notif::*;
 use serde::{Deserialize, Serialize};
 
@@ -50,6 +52,7 @@
   MessageToDeviceRequest(MessageToDeviceRequest),
   MessageReceiveConfirmation(MessageReceiveConfirmation),
   MessageToTunnelbrokerRequest(MessageToTunnelbrokerRequest),
+  FarcasterAPIRequest(FarcasterAPIRequest),
   Heartbeat(Heartbeat),
 }
 
@@ -59,6 +62,7 @@
 pub enum TunnelbrokerToDeviceMessage {
   ConnectionInitializationResponse(ConnectionInitializationResponse),
   DeviceToTunnelbrokerRequestStatus(DeviceToTunnelbrokerRequestStatus),
+  FarcasterAPIResponse(FarcasterAPIResponse),
   MessageToDevice(MessageToDevice),
   BadDeviceToken(BadDeviceToken),
   Heartbeat(Heartbeat),