diff --git a/lib/actions/message-actions.js b/lib/actions/message-actions.js
--- a/lib/actions/message-actions.js
+++ b/lib/actions/message-actions.js
@@ -196,6 +196,12 @@
   };
 };
 
+const sendReactionMessageActionTypes = Object.freeze({
+  started: 'SEND_REACTION_MESSAGE_STARTED',
+  success: 'SEND_REACTION_MESSAGE_SUCCESS',
+  failed: 'SEND_REACTION_MESSAGE_FAILED',
+});
+
 const saveMessagesActionType = 'SAVE_MESSAGES';
 const processMessagesActionType = 'PROCESS_MESSAGES';
 const messageStorePruneActionType = 'MESSAGE_STORE_PRUNE';
@@ -213,6 +219,7 @@
   sendMultimediaMessageActionTypes,
   sendMultimediaMessage,
   legacySendMultimediaMessage,
+  sendReactionMessageActionTypes,
   saveMessagesActionType,
   processMessagesActionType,
   messageStorePruneActionType,
diff --git a/lib/types/message-types.js b/lib/types/message-types.js
--- a/lib/types/message-types.js
+++ b/lib/types/message-types.js
@@ -540,6 +540,13 @@
   +interface: CallServerEndpointResultInfoInterface,
 };
 
+export type SendReactionMessagePayload = {
+  +serverID: string,
+  +threadID: string,
+  +time: number,
+  +newMessageInfos: $ReadOnlyArray<RawMessageInfo>,
+};
+
 export type SendTextMessageRequest = {
   +threadID: string,
   +localID?: string,
diff --git a/lib/types/redux-types.js b/lib/types/redux-types.js
--- a/lib/types/redux-types.js
+++ b/lib/types/redux-types.js
@@ -38,8 +38,10 @@
 import type {
   MessageStore,
   RawMultimediaMessageInfo,
+  RawReactionMessageInfo,
   FetchMessageInfosPayload,
   SendMessagePayload,
+  SendReactionMessagePayload,
   SaveMessagesPayload,
   NewMessagesPayload,
   MessageStorePrunePayload,
@@ -522,6 +524,25 @@
       +payload: SendMessagePayload,
       +loadingInfo: LoadingInfo,
     }
+  | {
+      +type: 'SEND_REACTION_MESSAGE_STARTED',
+      +loadingInfo?: LoadingInfo,
+      +payload: RawReactionMessageInfo,
+    }
+  | {
+      +type: 'SEND_REACTION_MESSAGE_FAILED',
+      +error: true,
+      +payload: Error & {
+        +targetMessageID: string,
+        +threadID: string,
+      },
+      +loadingInfo?: LoadingInfo,
+    }
+  | {
+      +type: 'SEND_REACTION_MESSAGE_SUCCESS',
+      +payload: SendReactionMessagePayload,
+      +loadingInfo: LoadingInfo,
+    }
   | {
       +type: 'SEARCH_USERS_STARTED',
       +payload?: void,