diff --git a/lib/actions/aux-user-actions.js b/lib/actions/aux-user-actions.js
new file mode 100644
--- /dev/null
+++ b/lib/actions/aux-user-actions.js
@@ -0,0 +1,5 @@
+// @flow
+
+const setFarcasterFriendsFIDActionType = 'SET_FARCASTER_FRIENDS_FID';
+
+export { setFarcasterFriendsFIDActionType };
diff --git a/lib/reducers/aux-user-reducer.js b/lib/reducers/aux-user-reducer.js
new file mode 100644
--- /dev/null
+++ b/lib/reducers/aux-user-reducer.js
@@ -0,0 +1,46 @@
+// @flow
+
+import { setFarcasterFriendsFIDActionType } from '../actions/aux-user-actions.js';
+import {
+  auxUserStoreOpsHandlers,
+  type AuxUserStoreOperation,
+  type ReplaceAuxUserInfoOperation,
+} from '../ops/aux-user-store-ops.js';
+import type { AuxUserStore } from '../types/aux-user-types.js';
+import type { BaseAction } from '../types/redux-types';
+
+const { processStoreOperations: processStoreOps } = auxUserStoreOpsHandlers;
+
+function reduceAuxUserStore(
+  state: AuxUserStore,
+  action: BaseAction,
+): {
+  +auxUserStore: AuxUserStore,
+  +auxUserStoreOperations: $ReadOnlyArray<AuxUserStoreOperation>,
+} {
+  if (action.type === setFarcasterFriendsFIDActionType) {
+    const replaceOperations: ReplaceAuxUserInfoOperation[] = [];
+    for (const farcasterUser of action.payload.farcasterUsers) {
+      replaceOperations.push({
+        type: 'replace_aux_user_info',
+        payload: {
+          id: farcasterUser.userID,
+          auxUserInfo: {
+            ...state.auxUserInfos[farcasterUser.userID],
+            fid: farcasterUser.farcasterID,
+          },
+        },
+      });
+    }
+    return {
+      auxUserStore: processStoreOps(state, replaceOperations),
+      auxUserStoreOperations: replaceOperations,
+    };
+  }
+  return {
+    auxUserStore: state,
+    auxUserStoreOperations: [],
+  };
+}
+
+export { reduceAuxUserStore };
diff --git a/lib/reducers/aux-user-reducer.test.js b/lib/reducers/aux-user-reducer.test.js
new file mode 100644
--- /dev/null
+++ b/lib/reducers/aux-user-reducer.test.js
@@ -0,0 +1,38 @@
+// @flow
+
+import { reduceAuxUserStore } from './aux-user-reducer.js';
+import { setFarcasterFriendsFIDActionType } from '../actions/aux-user-actions.js';
+
+jest.mock('../utils/config.js');
+
+describe('reduceAuxUserStore', () => {
+  it('should update aux user store with farcaster data for user', () => {
+    const oldAuxUserStore = {
+      auxUserInfos: {},
+    };
+
+    const updateAuxUserInfosAction = {
+      type: setFarcasterFriendsFIDActionType,
+      payload: {
+        farcasterUsers: [
+          {
+            userID: 'userID_1',
+            username: 'username_1',
+            farcasterID: 'farcasterID_1',
+          },
+        ],
+      },
+    };
+
+    expect(
+      reduceAuxUserStore(oldAuxUserStore, updateAuxUserInfosAction)
+        .auxUserStore,
+    ).toEqual({
+      auxUserInfos: {
+        userID_1: {
+          fid: 'farcasterID_1',
+        },
+      },
+    });
+  });
+});
diff --git a/lib/reducers/db-ops-reducer.test.js b/lib/reducers/db-ops-reducer.test.js
--- a/lib/reducers/db-ops-reducer.test.js
+++ b/lib/reducers/db-ops-reducer.test.js
@@ -14,6 +14,7 @@
   communityStoreOperations: [],
   integrityStoreOperations: [],
   syncedMetadataStoreOperations: [],
+  auxUserStoreOperations: [],
 };
 
 describe('DB ops reducer', () => {
diff --git a/lib/reducers/master-reducer.js b/lib/reducers/master-reducer.js
--- a/lib/reducers/master-reducer.js
+++ b/lib/reducers/master-reducer.js
@@ -1,5 +1,6 @@
 // @flow
 
+import { reduceAuxUserStore } from './aux-user-reducer.js';
 import reduceCalendarFilters from './calendar-filters-reducer.js';
 import { reduceCommunityStore } from './community-reducer.js';
 import reduceCustomerServer from './custom-server-reducer.js';
@@ -176,6 +177,11 @@
   const { syncedMetadataStore, syncedMetadataStoreOperations } =
     reduceSyncedMetadataStore(state.syncedMetadataStore, action);
 
+  const { auxUserStore, auxUserStoreOperations } = reduceAuxUserStore(
+    state.auxUserStore,
+    action,
+  );
+
   return {
     state: {
       ...state,
@@ -218,6 +224,7 @@
       communityStore,
       dbOpsStore: reduceDBOpsStore(state.dbOpsStore, action),
       syncedMetadataStore,
+      auxUserStore,
     },
     storeOperations: {
       draftStoreOperations,
@@ -229,6 +236,7 @@
       communityStoreOperations,
       integrityStoreOperations,
       syncedMetadataStoreOperations,
+      auxUserStoreOperations,
     },
   };
 }
diff --git a/lib/types/aux-user-types.js b/lib/types/aux-user-types.js
--- a/lib/types/aux-user-types.js
+++ b/lib/types/aux-user-types.js
@@ -1,5 +1,7 @@
 // @flow
 
+import type { FarcasterUser } from './identity-service-types';
+
 export type AuxUserInfo = { +fid: string };
 
 export type AuxUserInfos = { +[userID: string]: AuxUserInfo };
@@ -7,3 +9,7 @@
 export type AuxUserStore = {
   +auxUserInfos: AuxUserInfos,
 };
+
+export type SetFarcasterFriendsFIDPayload = {
+  +farcasterUsers: $ReadOnlyArray<FarcasterUser>,
+};
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
@@ -15,6 +15,10 @@
   QueueActivityUpdatesPayload,
   SetThreadUnreadStatusPayload,
 } from './activity-types.js';
+import type {
+  AuxUserStore,
+  SetFarcasterFriendsFIDPayload,
+} from './aux-user-types.js';
 import type {
   UpdateUserAvatarRequest,
   UpdateUserAvatarResponse,
@@ -164,6 +168,7 @@
   +communityStore: CommunityStore,
   +dbOpsStore: DBOpsStore,
   +syncedMetadataStore: SyncedMetadataStore,
+  +auxUserStore: AuxUserStore,
   ...
 };
 
@@ -1380,6 +1385,10 @@
         +type: 'SET_ACTIVE_SESSION_RECOVERY',
         +payload: SetActiveSessionRecoveryPayload,
       }
+    | {
+        +type: 'SET_FARCASTER_FRIENDS_FID',
+        +payload: SetFarcasterFriendsFIDPayload,
+      }
     | {
         +type: 'OPS_PROCESSING_FINISHED_ACTION_TYPE',
         +payload?: void,
diff --git a/lib/types/store-ops-types.js b/lib/types/store-ops-types.js
--- a/lib/types/store-ops-types.js
+++ b/lib/types/store-ops-types.js
@@ -19,6 +19,7 @@
 import type {
   ClientDBAuxUserInfo,
   ClientDBAuxUserStoreOperation,
+  AuxUserStoreOperation,
 } from '../ops/aux-user-store-ops.js';
 import type {
   ClientDBCommunityInfo,
@@ -67,6 +68,7 @@
   +communityStoreOperations: $ReadOnlyArray<CommunityStoreOperation>,
   +integrityStoreOperations: $ReadOnlyArray<IntegrityStoreOperation>,
   +syncedMetadataStoreOperations: $ReadOnlyArray<ClientDBSyncedMetadataStoreOperation>,
+  +auxUserStoreOperations: $ReadOnlyArray<AuxUserStoreOperation>,
 };
 
 export type ClientDBStoreOperations = {
diff --git a/lib/utils/reducers-utils.test.js b/lib/utils/reducers-utils.test.js
--- a/lib/utils/reducers-utils.test.js
+++ b/lib/utils/reducers-utils.test.js
@@ -90,6 +90,9 @@
       syncedMetadataStore: {
         syncedMetadata: {},
       },
+      auxUserStore: {
+        auxUserInfos: {},
+      },
     };
     state = {
       ...defaultState,
diff --git a/native/redux/default-state.js b/native/redux/default-state.js
--- a/native/redux/default-state.js
+++ b/native/redux/default-state.js
@@ -84,6 +84,9 @@
   communityStore: {
     communityInfos: {},
   },
+  auxUserStore: {
+    auxUserInfos: {},
+  },
   dbOpsStore: {
     queuedOps: [],
   },
diff --git a/native/redux/redux-setup.js b/native/redux/redux-setup.js
--- a/native/redux/redux-setup.js
+++ b/native/redux/redux-setup.js
@@ -301,6 +301,7 @@
     communityStoreOperations,
     integrityStoreOperations,
     syncedMetadataStoreOperations,
+    auxUserStoreOperations,
   } = storeOperations;
 
   const fixUnreadActiveThreadResult = fixUnreadActiveThread(state, action);
@@ -321,6 +322,7 @@
     communityStoreOperations,
     integrityStoreOperations,
     syncedMetadataStoreOperations,
+    auxUserStoreOperations,
   };
   state = {
     ...state,
diff --git a/native/redux/redux-utils.js b/native/redux/redux-utils.js
--- a/native/redux/redux-utils.js
+++ b/native/redux/redux-utils.js
@@ -2,6 +2,7 @@
 
 import { useSelector as reactReduxUseSelector } from 'react-redux';
 
+import { auxUserStoreOpsHandlers } from 'lib/ops/aux-user-store-ops.js';
 import { communityStoreOpsHandlers } from 'lib/ops/community-store-ops.js';
 import { integrityStoreOpsHandlers } from 'lib/ops/integrity-store-ops.js';
 import {
@@ -39,6 +40,7 @@
     integrityStoreOperations,
     communityStoreOperations,
     syncedMetadataStoreOperations,
+    auxUserStoreOperations,
   } = storeOperations;
 
   const convertedThreadStoreOperations =
@@ -61,6 +63,8 @@
     getKeyserversToRemoveFromNotifsStore(keyserverStoreOperations);
   const convertedIntegrityStoreOperations =
     integrityStoreOpsHandlers.convertOpsToClientDBOps(integrityStoreOperations);
+  const convertedAuxUserStoreOperations =
+    auxUserStoreOpsHandlers.convertOpsToClientDBOps(auxUserStoreOperations);
 
   try {
     const promises = [];
@@ -130,6 +134,13 @@
         ),
       );
     }
+    if (convertedAuxUserStoreOperations.length > 0) {
+      promises.push(
+        commCoreModule.processAuxUserStoreOperations(
+          convertedAuxUserStoreOperations,
+        ),
+      );
+    }
     await Promise.all(promises);
   } catch (e) {
     if (isTaskCancelledError(e)) {
diff --git a/native/redux/state-types.js b/native/redux/state-types.js
--- a/native/redux/state-types.js
+++ b/native/redux/state-types.js
@@ -3,6 +3,7 @@
 import type { Orientations } from 'react-native-orientation-locker';
 import type { PersistState } from 'redux-persist/es/types.js';
 
+import type { AuxUserStore } from 'lib/types/aux-user-types.js';
 import type { CommunityStore } from 'lib/types/community-types.js';
 import type { DBOpsStore } from 'lib/types/db-ops-types';
 import type { DraftStore } from 'lib/types/draft-types.js';
@@ -81,6 +82,7 @@
   +communityStore: CommunityStore,
   +dbOpsStore: DBOpsStore,
   +syncedMetadataStore: SyncedMetadataStore,
+  +auxUserStore: AuxUserStore,
 };
 
 export { nonUserSpecificFieldsNative };
diff --git a/web/redux/default-state.js b/web/redux/default-state.js
--- a/web/redux/default-state.js
+++ b/web/redux/default-state.js
@@ -86,6 +86,9 @@
   syncedMetadataStore: {
     syncedMetadata: {},
   },
+  auxUserStore: {
+    auxUserInfos: {},
+  },
 });
 
 export { defaultWebState };
diff --git a/web/redux/initial-state-gate.js b/web/redux/initial-state-gate.js
--- a/web/redux/initial-state-gate.js
+++ b/web/redux/initial-state-gate.js
@@ -127,6 +127,7 @@
             communityStoreOperations: [],
             integrityStoreOperations: [],
             syncedMetadataStoreOperations: [],
+            auxUserStoreOperations: [],
           },
           currentLoggedInUserID,
         );
diff --git a/web/redux/redux-setup.js b/web/redux/redux-setup.js
--- a/web/redux/redux-setup.js
+++ b/web/redux/redux-setup.js
@@ -30,6 +30,7 @@
   identityInvalidSessionDowngrade,
   invalidSessionRecovery,
 } from 'lib/shared/session-utils.js';
+import type { AuxUserStore } from 'lib/types/aux-user-types.js';
 import type { CommunityStore } from 'lib/types/community-types.js';
 import type { MessageID, DBOpsStore } from 'lib/types/db-ops-types.js';
 import type { DraftStore } from 'lib/types/draft-types.js';
@@ -124,6 +125,7 @@
   +communityStore: CommunityStore,
   +dbOpsStore: DBOpsStore,
   +syncedMetadataStore: SyncedMetadataStore,
+  +auxUserStore: AuxUserStore,
 };
 
 export type Action = $ReadOnly<
@@ -157,6 +159,7 @@
     communityStoreOperations: [],
     integrityStoreOperations: [],
     syncedMetadataStoreOperations: [],
+    auxUserStoreOperations: [],
   };
 
   if (
diff --git a/web/shared-worker/utils/store.js b/web/shared-worker/utils/store.js
--- a/web/shared-worker/utils/store.js
+++ b/web/shared-worker/utils/store.js
@@ -1,5 +1,6 @@
 // @flow
 
+import { auxUserStoreOpsHandlers } from 'lib/ops/aux-user-store-ops.js';
 import { communityStoreOpsHandlers } from 'lib/ops/community-store-ops.js';
 import { integrityStoreOpsHandlers } from 'lib/ops/integrity-store-ops.js';
 import { keyserverStoreOpsHandlers } from 'lib/ops/keyserver-store-ops.js';
@@ -103,6 +104,7 @@
     communityStoreOperations,
     integrityStoreOperations,
     syncedMetadataStoreOperations,
+    auxUserStoreOperations,
   } = storeOperations;
 
   const canUseDatabase = canUseDatabaseOnWeb(userID);
@@ -122,6 +124,8 @@
     syncedMetadataStoreOpsHandlers.convertOpsToClientDBOps(
       syncedMetadataStoreOperations,
     );
+  const convertedAuxUserStoreOperations =
+    auxUserStoreOpsHandlers.convertOpsToClientDBOps(auxUserStoreOperations);
 
   if (
     convertedThreadStoreOperations.length === 0 &&
@@ -130,7 +134,8 @@
     convertedKeyserverStoreOperations.length === 0 &&
     convertedCommunityStoreOperations.length === 0 &&
     convertedIntegrityStoreOperations.length === 0 &&
-    convertedSyncedMetadataStoreOperations.length === 0
+    convertedSyncedMetadataStoreOperations.length === 0 &&
+    convertedAuxUserStoreOperations.length === 0
   ) {
     return;
   }
@@ -151,6 +156,7 @@
         communityStoreOperations: convertedCommunityStoreOperations,
         integrityStoreOperations: convertedIntegrityStoreOperations,
         syncedMetadataStoreOperations: convertedSyncedMetadataStoreOperations,
+        auxUserStoreOperations: convertedAuxUserStoreOperations,
       },
     });
   } catch (e) {