diff --git a/lib/shared/farcaster/farcaster-api.js b/lib/shared/farcaster/farcaster-api.js
--- a/lib/shared/farcaster/farcaster-api.js
+++ b/lib/shared/farcaster/farcaster-api.js
@@ -541,6 +541,33 @@
   );
 }
 
+export type SendReactionInput = {
+  +conversationId: string,
+  +messageId: string,
+  +reaction: string,
+  +action: 'remove_reaction' | 'add_reaction',
+};
+
+function useSendFarcasterReaction(): (
+  input: SendReactionInput,
+) => Promise<void> {
+  const { sendFarcasterRequest } = useTunnelbroker();
+  return React.useCallback(
+    async (input: SendReactionInput) => {
+      const { action, ...payload } = input;
+      const method =
+        action === 'remove_reaction' ? { type: 'DELETE' } : { type: 'PUT' };
+      await sendFarcasterRequest({
+        apiVersion: 'v2',
+        endpoint: 'direct-cast-message-reaction',
+        method,
+        payload: JSON.stringify(payload),
+      });
+    },
+    [sendFarcasterRequest],
+  );
+}
+
 export {
   useSendFarcasterTextMessage,
   useFetchFarcasterMessages,
@@ -553,4 +580,5 @@
   useCreateFarcasterGroup,
   useGetFarcasterDirectCastUsers,
   useModifyFarcasterMembershipInput,
+  useSendFarcasterReaction,
 };
diff --git a/lib/shared/reaction-utils.js b/lib/shared/reaction-utils.js
--- a/lib/shared/reaction-utils.js
+++ b/lib/shared/reaction-utils.js
@@ -5,6 +5,7 @@
 import * as React from 'react';
 
 import { useProcessAndSendDMOperation } from './dm-ops/process-dm-ops.js';
+import { useSendFarcasterReaction } from './farcaster/farcaster-api.js';
 import { relationshipBlockedInEitherDirection } from './relationship-utils.js';
 import { useThreadHasPermission } from './thread-utils.js';
 import { threadSpecs } from './threads/thread-specs.js';
@@ -125,6 +126,7 @@
   const callSendReactionMessage = useSendReactionMessage();
   const dispatchActionPromise = useDispatchActionPromise();
   const processAndSendDMOperation = useProcessAndSendDMOperation();
+  const farcasterSendReaction = useSendFarcasterReaction();
 
   return React.useCallback(
     reaction => {
@@ -152,6 +154,7 @@
           processAndSendDMOperation,
           keyserverSendReaction: callSendReactionMessage,
           dispatchActionPromise,
+          farcasterSendReaction,
         },
       );
     },
@@ -160,10 +163,11 @@
       viewerID,
       reactions,
       threadInfo,
-      dispatchActionPromise,
+      showErrorAlert,
       processAndSendDMOperation,
       callSendReactionMessage,
-      showErrorAlert,
+      dispatchActionPromise,
+      farcasterSendReaction,
     ],
   );
 }
diff --git a/lib/shared/threads/protocols/farcaster-thread-protocol.js b/lib/shared/threads/protocols/farcaster-thread-protocol.js
--- a/lib/shared/threads/protocols/farcaster-thread-protocol.js
+++ b/lib/shared/threads/protocols/farcaster-thread-protocol.js
@@ -48,7 +48,10 @@
 import { updateTypes } from '../../../types/update-types-enum.js';
 import { farcasterThreadIDRegExp } from '../../../utils/validation-utils.js';
 import { generatePendingThreadColor } from '../../color-utils.js';
-import { type ModifyFarcasterMembershipInput } from '../../farcaster/farcaster-api.js';
+import {
+  type ModifyFarcasterMembershipInput,
+  type SendReactionInput,
+} from '../../farcaster/farcaster-api.js';
 import {
   conversationIDFromFarcasterThreadID,
   extractFIDFromUserID,
@@ -88,6 +91,8 @@
   LeaveThreadUtils,
   ProtocolSendMultimediaMessageInput,
   SendMultimediaMessageUtils,
+  ProtocolSendReactionInput,
+  SendReactionUtils,
 } from '../thread-spec.js';
 
 const farcasterThreadProtocol: ThreadProtocol<MemberInfoSansPermissions> = {
@@ -316,8 +321,20 @@
     };
   },
 
-  sendReaction: async (): Promise<mixed> => {
-    throw new Error('sendReaction method is not yet implemented');
+  sendReaction: async (
+    input: ProtocolSendReactionInput,
+    utils: SendReactionUtils,
+  ) => {
+    const { threadInfo, reaction, action, messageID } = input;
+    const conversationId = conversationIDFromFarcasterThreadID(threadInfo.id);
+    const payload: SendReactionInput = {
+      conversationId,
+      messageId: messageID,
+      reaction,
+      action,
+    };
+    const { farcasterSendReaction } = utils;
+    await farcasterSendReaction(payload);
   },
 
   addThreadMembers: async (
diff --git a/lib/shared/threads/thread-spec.js b/lib/shared/threads/thread-spec.js
--- a/lib/shared/threads/thread-spec.js
+++ b/lib/shared/threads/thread-spec.js
@@ -96,6 +96,7 @@
   CreateFarcasterGroupResult,
   CreateFarcasterGroupInput,
   ModifyFarcasterMembershipInput,
+  SendReactionInput,
 } from '../farcaster/farcaster-api.js';
 import type { FarcasterConversation } from '../farcaster/farcaster-conversation-types.js';
 import type { FetchMessagesFromDBType } from '../message-utils.js';
@@ -222,6 +223,7 @@
 export type SendReactionUtils = {
   +processAndSendDMOperation: OutboundDMOperationSpecification => Promise<void>,
   +keyserverSendReaction: SendReactionMessageRequest => Promise<SendMessageResult>,
+  +farcasterSendReaction: SendReactionInput => Promise<void>,
   +dispatchActionPromise: DispatchActionPromise,
 };
 
diff --git a/lib/types/tunnelbroker/farcaster-messages-types.js b/lib/types/tunnelbroker/farcaster-messages-types.js
--- a/lib/types/tunnelbroker/farcaster-messages-types.js
+++ b/lib/types/tunnelbroker/farcaster-messages-types.js
@@ -15,7 +15,8 @@
     }
   | { +type: 'PUT' }
   | { +type: 'POST' }
-  | { +type: 'STREAM' };
+  | { +type: 'STREAM' }
+  | { +type: 'DELETE' };
 
 export type FarcasterAPIRequest = {
   +type: 'FarcasterAPIRequest',