diff --git a/packages/server/src/db/migrate.ts b/packages/server/src/db/migrate.ts
index 044f9a0f..1c1ec615 100644
--- a/packages/server/src/db/migrate.ts
+++ b/packages/server/src/db/migrate.ts
@@ -60,7 +60,8 @@ export function runMigrations(db: Database.Database): void {
       name: 'users',
       columns: [
         { name: 'home_instance', type: 'TEXT' },
-        { name: 'replicated_instances', type: "TEXT DEFAULT '[]'" }
+        { name: 'replicated_instances', type: "TEXT DEFAULT '[]'" },
+        { name: 'home_user_id', type: 'TEXT' }
       ]
     },
     {
diff --git a/packages/server/src/db/schema.ts b/packages/server/src/db/schema.ts
index 911b39d7..899e93e3 100644
--- a/packages/server/src/db/schema.ts
+++ b/packages/server/src/db/schema.ts
@@ -10,6 +10,7 @@ export const users = sqliteTable('users', {
   customStatus: text('custom_status'),
   isAdmin: integer('is_admin').default(0),
   homeInstance: text('home_instance'),
+  homeUserId: text('home_user_id'),
   replicatedInstances: text('replicated_instances').default('[]'),
   createdAt: integer('created_at').notNull(),
 });
diff --git a/packages/server/src/routes/auth.ts b/packages/server/src/routes/auth.ts
index 15ea3d35..a67108ac 100644
--- a/packages/server/src/routes/auth.ts
+++ b/packages/server/src/routes/auth.ts
@@ -17,7 +17,7 @@ export async function authRoutes(app: FastifyInstance): Promise<void> {
       },
     },
   }, async (request, reply) => {
-    const { username, password, displayName, homeInstance } = request.body;
+    const { username, password, displayName, homeInstance, homeUserId } = request.body;
 
     if (!username || typeof username !== 'string') {
       return reply.code(400).send({ error: 'Username is required', statusCode: 400 });
@@ -102,6 +102,7 @@ export async function authRoutes(app: FastifyInstance): Promise<void> {
       status: 'online',
       isAdmin: isFirstUser ? 1 : 0,
       homeInstance: homeInstance || null,
+      homeUserId: (homeInstance && homeUserId && typeof homeUserId === 'string') ? homeUserId : null,
       createdAt: now,
     }).run();
 
diff --git a/packages/server/src/routes/users.ts b/packages/server/src/routes/users.ts
index f051accd..70ff034e 100644
--- a/packages/server/src/routes/users.ts
+++ b/packages/server/src/routes/users.ts
@@ -38,7 +38,7 @@ export async function userRoutes(app: FastifyInstance): Promise<void> {
   });
 
   app.patch<{ Body: UpdateUserRequest }>('/api/users/@me', { preHandler: authenticate }, async (request, reply) => {
-    const { displayName, avatar, customStatus, status, replicatedInstances } = request.body;
+    const { displayName, avatar, customStatus, status, replicatedInstances, homeUserId } = request.body;
     const db = getDb();
 
     const updateData: Record<string, string | null | undefined> = {};
@@ -97,6 +97,14 @@ export async function userRoutes(app: FastifyInstance): Promise<void> {
       updateData.replicatedInstances = JSON.stringify(replicatedInstances);
     }
 
+    if (homeUserId !== undefined) {
+      // Only allow setting homeUserId for replicated users (has homeInstance)
+      const currentUser = db.select().from(schema.users).where(eq(schema.users.id, request.userId)).get();
+      if (currentUser?.homeInstance && typeof homeUserId === 'string' && homeUserId.length > 0) {
+        updateData.homeUserId = homeUserId;
+      }
+    }
+
     if (Object.keys(updateData).length === 0) {
       return reply.code(400).send({ error: 'No fields to update', statusCode: 400 });
     }
diff --git a/packages/server/src/utils/sanitize.ts b/packages/server/src/utils/sanitize.ts
index 39d6c379..07544764 100644
--- a/packages/server/src/utils/sanitize.ts
+++ b/packages/server/src/utils/sanitize.ts
@@ -21,6 +21,7 @@ export function sanitizeUser(row: typeof schema.users.$inferSelect): User {
     isAdmin: row.isAdmin === 1,
     createdAt: row.createdAt,
     homeInstance: row.homeInstance ?? null,
+    homeUserId: row.homeUserId ?? null,
     replicatedInstances,
   };
 }
diff --git a/packages/shared/src/types.ts b/packages/shared/src/types.ts
index 90910815..8a31ab72 100644
--- a/packages/shared/src/types.ts
+++ b/packages/shared/src/types.ts
@@ -10,6 +10,7 @@ export interface User {
   isAdmin: boolean;
   createdAt: number;
   homeInstance: string | null;
+  homeUserId: string | null;
   replicatedInstances: ReplicatedInstance[];
 }
 
@@ -253,6 +254,7 @@ export interface RegisterRequest {
   password: string;
   displayName?: string;
   homeInstance?: string;
+  homeUserId?: string;
 }
 
 export interface LoginRequest {
@@ -293,6 +295,7 @@ export interface UpdateUserRequest {
   customStatus?: string;
   status?: UserStatus;
   replicatedInstances?: ReplicatedInstance[];
+  homeUserId?: string;
 }
 
 export interface UpdateMemberRequest {
diff --git a/packages/web/src/components/chat/FriendsPage.test.tsx b/packages/web/src/components/chat/FriendsPage.test.tsx
index 61c084cf..f561f151 100644
--- a/packages/web/src/components/chat/FriendsPage.test.tsx
+++ b/packages/web/src/components/chat/FriendsPage.test.tsx
@@ -62,6 +62,7 @@ const makeRequest = (overrides: Partial<FriendRequest> = {}): FriendRequest => (
     isAdmin: false,
     createdAt: Date.now(),
     homeInstance: null,
+    homeUserId: null,
     replicatedInstances: [],
   },
   ...overrides,
@@ -218,6 +219,7 @@ describe('FriendsPage', () => {
           isAdmin: false,
           createdAt: Date.now(),
           homeInstance: null,
+          homeUserId: null,
           replicatedInstances: [],
         },
       });
@@ -265,6 +267,7 @@ describe('FriendsPage', () => {
           isAdmin: false,
           createdAt: Date.now(),
           homeInstance: null,
+          homeUserId: null,
           replicatedInstances: [],
         },
       });
@@ -307,6 +310,7 @@ describe('FriendsPage', () => {
           isAdmin: false,
           createdAt: Date.now(),
           homeInstance: null,
+          homeUserId: null,
           replicatedInstances: [],
         },
       });
diff --git a/packages/web/src/components/layout/MemberSidebar.tsx b/packages/web/src/components/layout/MemberSidebar.tsx
index ab34328e..4d6a4e6a 100644
--- a/packages/web/src/components/layout/MemberSidebar.tsx
+++ b/packages/web/src/components/layout/MemberSidebar.tsx
@@ -2,8 +2,6 @@ import React, { useMemo } from 'react';
 import type { MemberWithUser } from '@backspace/shared';
 import { useServerStore } from '../../stores/serverStore';
 import { useUIStore } from '../../stores/uiStore';
-import { useAuthStore } from '../../stores/authStore';
-import { resolveDisplayIdentity } from '../../utils/identity';
 import { Avatar } from '../ui/Avatar';
 import { Username } from '../ui/Username';
 
@@ -48,7 +46,6 @@ export function MemberSidebar() {
   const currentServerId = useServerStore((s) => s.currentServerId);
   const memberListOpen = useUIStore((s) => s.memberListOpen);
   const openUserProfile = useUIStore((s) => s.openUserProfile);
-  const authUser = useAuthStore((s) => s.user);
 
   const server = servers.find(s => s.id === currentServerId);
   const ownerId = server?.ownerId;
@@ -100,7 +97,6 @@ export function MemberSidebar() {
   const renderMember = (member: MemberWithUser, isOffline = false) => {
     const displayName = member.user.displayName ?? member.user.username;
     const colorStyle = isOffline ? undefined : getMemberColor(member);
-    const resolvedUser = resolveDisplayIdentity(member.user, authUser ?? null);
     return (
       <div
         key={member.userId}
@@ -114,7 +110,6 @@ export function MemberSidebar() {
           status={isOffline ? 'offline' : member.user.status}
           className={isOffline ? 'opacity-60' : undefined}
           user={member.user}
-          userId={resolvedUser.id}
         />
         <div className="flex-1 min-w-0">
           <Username
diff --git a/packages/web/src/components/ui/Avatar.tsx b/packages/web/src/components/ui/Avatar.tsx
index 552e3359..0f5dc8f7 100644
--- a/packages/web/src/components/ui/Avatar.tsx
+++ b/packages/web/src/components/ui/Avatar.tsx
@@ -48,7 +48,7 @@ export function Avatar({ src, name, size = 40, status, className = '', onClick,
   const initials = name.charAt(0).toUpperCase();
   // Match prototype: 24px→10px, 32-34px→12px, 40px→15px, 56px+→18px
   const fontPx = size <= 24 ? 10 : size <= 34 ? 12 : size <= 44 ? 15 : 18;
-  const gradient = getAvatarGradient(userId ?? user?.id, name);
+  const gradient = getAvatarGradient(userId ?? user?.homeUserId ?? user?.id, name);
 
   const handleClick = (e: React.MouseEvent) => {
     if (onClick) {
diff --git a/packages/web/src/components/ui/UserProfilePopout.tsx b/packages/web/src/components/ui/UserProfilePopout.tsx
index 7c84c4de..53fbfce0 100644
--- a/packages/web/src/components/ui/UserProfilePopout.tsx
+++ b/packages/web/src/components/ui/UserProfilePopout.tsx
@@ -55,7 +55,7 @@ export function UserProfilePopout({ user, onClose, position }: UserProfilePopout
       <div
         className="h-[48px] rounded-t-[12px]"
         style={{
-          background: getAvatarGradient(user.id, displayName).gradient,
+          background: getAvatarGradient(user.homeUserId ?? user.id, displayName).gradient,
           opacity: 0.6,
         }}
       />
diff --git a/packages/web/src/components/voice/StreamTile.tsx b/packages/web/src/components/voice/StreamTile.tsx
index 5e2d064a..e2942509 100644
--- a/packages/web/src/components/voice/StreamTile.tsx
+++ b/packages/web/src/components/voice/StreamTile.tsx
@@ -1,7 +1,6 @@
 import React, { useRef, useEffect, useState, useCallback } from 'react';
 import { Avatar } from '../ui/Avatar';
 import { useVoiceStore } from '../../stores/voiceStore';
-import { useAuthStore } from '../../stores/authStore';
 import { getActiveRoom, setStreamSubscription } from '../../hooks/useLiveKit';
 import { ScreenShareSettingsPopover } from './ScreenShareSettingsPopover';
 import { stopScreenShare, changeScreenShare } from '../../utils/screenShare';
@@ -24,8 +23,7 @@ export function StreamTile({ tile, large }: StreamTileProps) {
   const { participant } = tile;
   const isLocal = participant.isLocal;
   const userId = participant.userId;
-  const homeUser = useAuthStore((s) => s.user);
-  const avatarUserId = isLocal ? (homeUser?.id ?? userId) : userId;
+  const avatarUserId = participant.homeUserId ?? userId;
 
   const isWatching = watchingStreams.has(userId);
   const streamVolume = streamVolumes.get(userId) ?? 100;
diff --git a/packages/web/src/components/voice/VoiceChannel.tsx b/packages/web/src/components/voice/VoiceChannel.tsx
index 86fab9cd..ccde919b 100644
--- a/packages/web/src/components/voice/VoiceChannel.tsx
+++ b/packages/web/src/components/voice/VoiceChannel.tsx
@@ -1,7 +1,5 @@
 import React from 'react';
 import { useVoiceStore } from '../../stores/voiceStore';
-import { useAuthStore } from '../../stores/authStore';
-import { isSelf } from '../../utils/identity';
 
 const EMPTY_VOICE_USERS: string[] = [];
 import { useServerStore } from '../../stores/serverStore';
@@ -20,8 +18,11 @@ export function VoiceChannel({ channelId, channelName, onClick }: VoiceChannelPr
   const localIsDeafened = useVoiceStore((s) => s.isDeafened);
   const localIsMuted = useVoiceStore((s) => s.isMuted);
   const voiceUserStates = useVoiceStore((s) => s.voiceUserStates);
-  const authUser = useAuthStore((s) => s.user);
-  const currentUserId = authUser?.id;
+  const currentUserId = useVoiceStore((s) => {
+    // Derive from participants — avoids unnecessary authStore dependency
+    const local = s.participants.find(p => p.isLocal);
+    return local?.userId ?? null;
+  });
   const members = useServerStore((s) => s.members);
   const isActive = currentVoiceChannel === channelId;
 
@@ -75,7 +76,7 @@ export function VoiceChannel({ channelId, channelName, onClick }: VoiceChannelPr
                   name={displayName}
                   size={24}
                   status={status}
-                  userId={(authUser && member?.user && isSelf(member.user, authUser)) ? authUser.id : userId}
+                  userId={member?.user.homeUserId ?? userId}
                 />
                 <span className="text-[13px] text-txt-secondary truncate flex-1 min-w-0">{displayName}</span>
                 {/* Status badges */}
diff --git a/packages/web/src/components/voice/VoiceUser.tsx b/packages/web/src/components/voice/VoiceUser.tsx
index 1abe2aa1..42e7e632 100644
--- a/packages/web/src/components/voice/VoiceUser.tsx
+++ b/packages/web/src/components/voice/VoiceUser.tsx
@@ -1,7 +1,6 @@
 import React, { useRef, useEffect, useState, useCallback } from 'react';
 import { Avatar } from '../ui/Avatar';
 import { useVoiceStore } from '../../stores/voiceStore';
-import { useAuthStore } from '../../stores/authStore';
 import type { UserTile } from '../../hooks/useLiveKit';
 
 interface VoiceUserProps {
@@ -21,8 +20,7 @@ export function VoiceUser({ tile, large }: VoiceUserProps) {
 
   const perUserVolume = participantVolumes.get(participant.userId) ?? 100;
   const isLocal = participant.isLocal;
-  const homeUser = useAuthStore((s) => s.user);
-  const avatarUserId = isLocal ? (homeUser?.id ?? participant.userId) : participant.userId;
+  const avatarUserId = participant.homeUserId ?? participant.userId;
 
   // --- VIDEO & UI ---
 
diff --git a/packages/web/src/hooks/useLiveKit.ts b/packages/web/src/hooks/useLiveKit.ts
index b2637ee1..75725d57 100644
--- a/packages/web/src/hooks/useLiveKit.ts
+++ b/packages/web/src/hooks/useLiveKit.ts
@@ -12,7 +12,7 @@ import {
   LocalAudioTrack,
   LocalTrackPublication,
 } from 'livekit-client';
-import { getApiForOrigin, getChannelOrigin } from '../stores/serverStore';
+import { getApiForOrigin, getChannelOrigin, useServerStore } from '../stores/serverStore';
 import { useVoiceStore } from '../stores/voiceStore';
 import { AudioManager } from '../audio/AudioManager';
 import { SpeakingDetector } from '../audio/SpeakingDetector';
@@ -37,6 +37,7 @@ export interface ParticipantInfo {
   identity: string;
   userId: string;
   username: string;
+  homeUserId: string | null;
   isMuted: boolean;
   isDeafened: boolean;
   isCameraOn: boolean;
@@ -152,6 +153,8 @@ export function useLiveKit() {
     const processParticipant = (p: Participant, isLocal: boolean) => {
       if (!p.identity) return;
       const { userId, username } = parseIdentity(p.identity);
+      const memberMatch = useServerStore.getState().members.find(m => m.userId === userId);
+      const homeUserId = memberMatch?.user.homeUserId ?? null;
       let audioTrack: MediaStreamTrack | null = null;
       let videoTrack: MediaStreamTrack | null = null;
       let screenTrack: MediaStreamTrack | null = null;
@@ -194,6 +197,7 @@ export function useLiveKit() {
         identity: p.identity,
         userId,
         username,
+        homeUserId,
         isMuted: isPartMuted,
         isDeafened: isPartDeafened,
         isCameraOn: !!videoTrack,
diff --git a/packages/web/src/stores/instanceStore.ts b/packages/web/src/stores/instanceStore.ts
index ce6151c4..20fdd6c2 100644
--- a/packages/web/src/stores/instanceStore.ts
+++ b/packages/web/src/stores/instanceStore.ts
@@ -150,6 +150,7 @@ export const useInstanceStore = create<InstanceState>((set, get) => ({
           password,
           displayName: displayName || currentUser.displayName || undefined,
           homeInstance,
+          homeUserId: currentUser.id,
         });
       } catch (err) {
         const message = (err as Error).message;
@@ -162,6 +163,7 @@ export const useInstanceStore = create<InstanceState>((set, get) => ({
               password,
               displayName: displayName || currentUser.displayName || undefined,
               homeInstance,
+              homeUserId: currentUser.id,
             });
           } catch (err2) {
             const msg2 = (err2 as Error).message;
@@ -380,6 +382,14 @@ export const useInstanceStore = create<InstanceState>((set, get) => ({
             // Non-critical — keep cached label
           }
 
+          // Backfill homeUserId if missing (existing federated users before this field existed)
+          if (user.homeInstance && !user.homeUserId) {
+            const homeUser = useAuthStore.getState().user;
+            if (homeUser) {
+              client.users.update({ homeUserId: homeUser.id }).catch(() => {});
+            }
+          }
+
           const connectedInstance: ConnectedInstance = {
             origin,
             label,