feat: Introduce runtime configuration for domain and enhance S3 storage settings with public base URL and Contabo support.

docker-compose.yml

@@ -72,6 +72,9 @@ services:
       # Port configuration (auto or specific port)
       PORT: ${PORT:-3000}
 
+      # S3 Storage public URL (for custom S3 providers like R2, B2, Contabo)
+      STORAGE_PUBLIC_BASE_URL: ${STORAGE_PUBLIC_BASE_URL:-}
+
       # Node environment
       NODE_ENV: production
     volumes:

src/app/api/auth/register/route.ts

@@ -15,6 +15,7 @@ const registerSchema = z.object({
     // S3-compatible storage credentials
     storageProvider: z.string().min(1),
     storageEndpoint: z.string().nullable().optional(),
+    storagePublicBaseUrl: z.string().nullable().optional(),
     storageRegion: z.string().min(1),
     storageBucket: z.string().min(1),
     storageAccessKey: z.string().min(10),
@@ -71,6 +72,7 @@ export async function POST(request: Request) {
             data.displayName,
             data.storageProvider,
             data.storageEndpoint || null,
+            data.storagePublicBaseUrl || null,
             data.storageRegion,
             data.storageBucket,
             data.storageAccessKey,

src/app/api/bots/route.ts

@@ -78,6 +78,7 @@ export async function POST(request: Request) {
         botAvatarUrl = await generateAndUploadAvatarToUserStorage(
           botHandle,
           user.storageEndpoint || undefined,
+          user.storagePublicBaseUrl || undefined,
           user.storageRegion || 'auto',
           user.storageBucket,
           accessKeyId,

src/app/api/config/route.ts

@@ -0,0 +1,7 @@
+import { NextResponse } from 'next/server';
+
+export async function GET() {
+  return NextResponse.json({
+    domain: process.env.NEXT_PUBLIC_NODE_DOMAIN || process.env.NODE_DOMAIN || 'localhost:3000',
+  });
+}

src/app/api/media/upload/route.ts

@@ -64,6 +64,7 @@ export async function POST(req: NextRequest) {
             file.type,
             user.storageProvider as any,
             user.storageEndpoint,
+            user.storagePublicBaseUrl,
             user.storageRegion || 'us-east-1',
             user.storageBucket || '',
             user.storageAccessKeyEncrypted,

src/app/chat/page.tsx

@@ -4,7 +4,7 @@ import { useState, useEffect, useRef } from 'react';
 import { useAuth } from '@/lib/contexts/AuthContext';
 import { signedAPI } from '@/lib/api/signed-fetch';
 import { ArrowLeft, Send, Loader2, MessageCircle, Search, Plus, Trash2, MoreVertical } from 'lucide-react';
-import { formatFullHandle } from '@/lib/utils/handle';
+import { useFormattedHandle } from '@/lib/utils/handle';
 import { useRouter, useSearchParams } from 'next/navigation';
 
 interface Conversation {
@@ -43,6 +43,7 @@ export default function ChatPage() {
     // Chat Data State
     const [conversations, setConversations] = useState<Conversation[]>([]);
     const [selectedConversation, setSelectedConversation] = useState<Conversation | null>(null);
+    const selectedHandle = selectedConversation ? useFormattedHandle(selectedConversation.participant2.handle) : '';
     const [messages, setMessages] = useState<Message[]>([]);
     const [newMessage, setNewMessage] = useState('');
     const [loading, setLoading] = useState(true);
@@ -389,7 +390,7 @@ export default function ChatPage() {
                         <div style={{ flex: 1, minWidth: 0 }}>
                             <div style={{ fontWeight: 600, fontSize: '15px' }}>{selectedConversation.participant2.displayName}</div>
                             <div style={{ fontSize: '12px', color: 'var(--foreground-tertiary)', whiteSpace: 'nowrap', overflow: 'hidden', textOverflow: 'ellipsis' }}>
-                                {formatFullHandle(selectedConversation.participant2.handle)}
+                                {selectedHandle}
                             </div>
                         </div>
                         <button

src/app/explore/page.tsx

@@ -5,7 +5,7 @@ import Link from 'next/link';
 import { SearchIcon, TrendingIcon, UsersIcon } from '@/components/Icons';
 import { PostCard } from '@/components/PostCard';
 import { Post } from '@/lib/types';
-import { formatFullHandle } from '@/lib/utils/handle';
+import { useFormattedHandle } from '@/lib/utils/handle';
 import { Bot, Network, Server, EyeOff } from 'lucide-react';
 import { useAuth } from '@/lib/contexts/AuthContext';
 
@@ -21,6 +21,7 @@ interface User {
 }
 
 function UserCard({ user }: { user: User }) {
+    const fullHandle = useFormattedHandle(user.handle);
     return (
         <Link href={`/u/${user.handle}`} className="user-card">
             <div className="avatar">
@@ -52,7 +53,7 @@ function UserCard({ user }: { user: User }) {
                         </span>
                     )}
                 </div>
-                <div className="user-card-handle">{formatFullHandle(user.handle)}</div>
+                <div className="user-card-handle">{fullHandle}</div>
                 {user.bio && <div className="user-card-bio">{user.bio}</div>}
             </div>
         </Link>

src/app/layout.tsx

@@ -57,6 +57,7 @@ export const dynamic = 'force-dynamic';
 import { AuthProvider } from '@/lib/contexts/AuthContext';
 import { ToastProvider } from '@/lib/contexts/ToastContext';
 import { AccentColorProvider } from '@/lib/contexts/AccentColorContext';
+import { ConfigProvider } from '@/lib/contexts/ConfigContext';
 import { LayoutWrapper } from '@/components/LayoutWrapper';
 
 export default function RootLayout({
@@ -67,15 +68,17 @@ export default function RootLayout({
   return (
     <html lang="en" className={`${inter.variable} ${sairaCondensed.variable}`}>
       <body>
-        <AuthProvider>
-          <AccentColorProvider>
-            <ToastProvider>
-              <LayoutWrapper>
-                {children}
-              </LayoutWrapper>
-            </ToastProvider>
-          </AccentColorProvider>
-        </AuthProvider>
+        <ConfigProvider>
+          <AuthProvider>
+            <AccentColorProvider>
+              <ToastProvider>
+                <LayoutWrapper>
+                  {children}
+                </LayoutWrapper>
+              </ToastProvider>
+            </AccentColorProvider>
+          </AuthProvider>
+        </ConfigProvider>
       </body>
     </html>
   );

src/app/login/page.tsx

@@ -34,6 +34,7 @@ export default function LoginPage() {
     const [displayName, setDisplayName] = useState('');
     const [storageProvider, setStorageProvider] = useState('r2');
     const [storageEndpoint, setStorageEndpoint] = useState('');
+    const [storagePublicBaseUrl, setStoragePublicBaseUrl] = useState('');
     const [storageRegion, setStorageRegion] = useState('auto');
     const [storageBucket, setStorageBucket] = useState('');
     const [storageAccessKey, setStorageAccessKey] = useState('');
@@ -252,6 +253,7 @@ export default function LoginPage() {
                     displayName,
                     storageProvider,
                     storageEndpoint: storageEndpoint || null,
+                    storagePublicBaseUrl: storagePublicBaseUrl || null,
                     storageRegion,
                     storageBucket,
                     storageAccessKey,
@@ -573,6 +575,7 @@ export default function LoginPage() {
                                             <option value="r2">Cloudflare R2 (10GB free)</option>
                                             <option value="b2">Backblaze B2 (10GB free)</option>
                                             <option value="wasabi">Wasabi</option>
+                                            <option value="contabo">Contabo S3</option>
                                             <option value="s3">AWS S3</option>
                                             <option value="minio">MinIO / Self-hosted</option>
                                             <option value="other">Other S3-compatible</option>
@@ -611,22 +614,49 @@ export default function LoginPage() {
                                     </div>
                                 </div>
 
-                                {/* S3 Credentials - Full Width */}
-                                <div style={{ marginBottom: '16px' }}>
-                                    <label style={{ display: 'block', marginBottom: '6px', fontSize: '14px', fontWeight: 500 }}>
-                                        Endpoint URL (optional for AWS)
-                                    </label>
-                                    <input
-                                        type="text"
-                                        className="input"
-                                        value={storageEndpoint}
-                                        onChange={(e) => setStorageEndpoint(e.target.value)}
-                                        placeholder="https://<account>.r2.cloudflarestorage.com"
-                                    />
-                                    <div style={{ fontSize: '11px', color: 'var(--foreground-tertiary)', marginTop: '4px' }}>
-                                        Leave empty for AWS S3. Required for R2, B2, MinIO.
+                                {/* Endpoint URL - only show for providers that need it (R2, B2, Contabo, MinIO, Other) */}
+                                {(storageProvider === 'r2' || storageProvider === 'b2' || storageProvider === 'contabo' || storageProvider === 'minio' || storageProvider === 'other') && (
+                                    <div style={{ marginBottom: '16px' }}>
+                                        <label style={{ display: 'block', marginBottom: '6px', fontSize: '14px', fontWeight: 500 }}>
+                                            Endpoint URL
+                                        </label>
+                                        <input
+                                            type="text"
+                                            className="input"
+                                            value={storageEndpoint}
+                                            onChange={(e) => setStorageEndpoint(e.target.value)}
+                                            placeholder={storageProvider === 'contabo' ? 'https://s3.eu2.contabo.com' : 'https://<account>.r2.cloudflarestorage.com'}
+                                            required
+                                        />
+                                        <div style={{ fontSize: '11px', color: 'var(--foreground-tertiary)', marginTop: '4px' }}>
+                                            {storageProvider === 'contabo' ? 'S3 API endpoint from Contabo dashboard (e.g., https://s3.eu2.contabo.com)' :
+                                             'S3-compatible endpoint URL for uploads.'}
+                                        </div>
                                     </div>
-                                </div>
+                                )}
+
+                                {/* Public Base URL - only show for providers that need it (R2, B2, Contabo, Other) */}
+                                {(storageProvider === 'r2' || storageProvider === 'b2' || storageProvider === 'contabo' || storageProvider === 'other') && (
+                                    <div style={{ marginBottom: '16px' }}>
+                                        <label style={{ display: 'block', marginBottom: '6px', fontSize: '14px', fontWeight: 500 }}>
+                                            Public Base URL
+                                        </label>
+                                        <input
+                                            type="text"
+                                            className="input"
+                                            value={storagePublicBaseUrl}
+                                            onChange={(e) => setStoragePublicBaseUrl(e.target.value)}
+                                            placeholder={storageProvider === 'contabo' ? 'https://usc1.contabostorage.com/d5bec82ae49b444d8314dcb13654dd1d:your-bucket' : 'https://pub-xxx.r2.dev'}
+                                            required
+                                        />
+                                        <div style={{ fontSize: '11px', color: 'var(--foreground-tertiary)', marginTop: '4px' }}>
+                                            {storageProvider === 'contabo' ? 'Public URL from Contabo (format: https://region.contabostorage.com/account-id:bucket)' :
+                                             storageProvider === 'r2' ? 'Public bucket URL from R2 dashboard (e.g., https://pub-xxx.r2.dev)' :
+                                             storageProvider === 'b2' ? 'Public bucket URL from B2 dashboard (e.g., https://f000.backblazeb2.com/file/bucket)' :
+                                             'Public URL where files are accessible (without trailing slash)'}
+                                        </div>
+                                    </div>
+                                )}
 
                                 <div style={{ display: 'grid', gridTemplateColumns: '1fr 1fr', gap: '16px', marginBottom: '16px' }}>
                                     <div>

src/app/search/page.tsx

@@ -3,7 +3,7 @@
 import { useState, useEffect, useCallback } from 'react';
 import Link from 'next/link';
 import { useSearchParams, useRouter } from 'next/navigation';
-import { formatFullHandle } from '@/lib/utils/handle';
+import { useFormattedHandle } from '@/lib/utils/handle';
 import { PostCard } from '@/components/PostCard';
 import { Post } from '@/lib/types';
 import { Bot } from 'lucide-react';
@@ -65,6 +65,7 @@ const FlagIcon = () => (
 );
 
 function UserCard({ user }: { user: User }) {
+    const fullHandle = useFormattedHandle(user.handle);
     return (
         <Link
             href={`/@${user.handle}`}
@@ -107,7 +108,7 @@ function UserCard({ user }: { user: User }) {
                         </span>
                     )}
                 </div>
-                <div style={{ color: 'var(--foreground-tertiary)', fontSize: '14px' }}>{formatFullHandle(user.handle)}</div>
+                <div style={{ color: 'var(--foreground-tertiary)', fontSize: '14px' }}>{fullHandle}</div>
                 {user.bio && (
                     <div style={{
                         color: 'var(--foreground-secondary)',

src/app/u/[handle]/page.tsx

@@ -8,7 +8,7 @@ import { PostCard } from '@/components/PostCard';
 import { User, Post } from '@/lib/types';
 import AutoTextarea from '@/components/AutoTextarea';
 import { Rocket, MoreHorizontal, Mail, Camera } from 'lucide-react';
-import { formatFullHandle } from '@/lib/utils/handle';
+import { useFormattedHandle } from '@/lib/utils/handle';
 import { Bot } from 'lucide-react';
 import { useAuth } from '@/lib/contexts/AuthContext';
 
@@ -35,6 +35,7 @@ const stripHtml = (html: string | null | undefined): string | null => {
 };
 
 function UserRow({ user }: { user: UserSummary }) {
+    const fullHandle = useFormattedHandle(user.handle);
     return (
         <Link href={`/u/${user.handle}`} className="user-row">
             <div className="avatar">
@@ -66,7 +67,7 @@ function UserRow({ user }: { user: UserSummary }) {
                         </span>
                     )}
                 </div>
-                <div style={{ color: 'var(--foreground-tertiary)', fontSize: '13px' }}>{formatFullHandle(user.handle)}</div>
+                <div style={{ color: 'var(--foreground-tertiary)', fontSize: '13px' }}>{fullHandle}</div>
                 {user.bio && stripHtml(user.bio) && (
                     <div className="user-row-bio">{stripHtml(user.bio)}</div>
                 )}
@@ -82,6 +83,7 @@ export default function ProfilePage() {
     const { isIdentityUnlocked, signUserAction } = useAuth();
 
     const [user, setUser] = useState<User | null>(null);
+    const userFullHandle = user ? useFormattedHandle(user.handle) : '';
     const [posts, setPosts] = useState<Post[]>([]);
     const [likedPosts, setLikedPosts] = useState<Post[]>([]);
     const [currentUser, setCurrentUser] = useState<{ id: string; handle: string } | null>(null);
@@ -719,7 +721,7 @@ export default function ProfilePage() {
                     {/* User Info */}
                     <div style={{ padding: '12px 0' }}>
                         <h2 style={{ fontSize: '20px', fontWeight: 700 }}>{user.displayName || user.handle}</h2>
-                        <p style={{ color: 'var(--foreground-tertiary)' }}>{formatFullHandle(user.handle)}</p>
+                        <p style={{ color: 'var(--foreground-tertiary)' }}>{userFullHandle}</p>
 
                         {user.bio && (
                             <p style={{ marginTop: '12px', lineHeight: 1.5 }}>{user.bio}</p>

src/components/Compose.tsx

@@ -5,7 +5,7 @@ import AutoTextarea from '@/components/AutoTextarea';
 import { Post, Attachment } from '@/lib/types';
 import { ImageIcon, AlertTriangle, Film } from 'lucide-react';
 import { VideoEmbed } from '@/components/VideoEmbed';
-import { formatFullHandle } from '@/lib/utils/handle';
+import { useFormattedHandle } from '@/lib/utils/handle';
 import { useAuth } from '@/lib/contexts/AuthContext';
 
 interface MediaAttachment extends Attachment {
@@ -22,6 +22,7 @@ interface ComposeProps {
 
 export function Compose({ onPost, replyingTo, onCancelReply, placeholder = "What's happening?", isReply }: ComposeProps) {
     const { isIdentityUnlocked } = useAuth();
+    const replyToHandle = replyingTo ? useFormattedHandle(replyingTo.author.handle) : '';
     const [content, setContent] = useState('');
     const [isPosting, setIsPosting] = useState(false);
     const [attachments, setAttachments] = useState<MediaAttachment[]>([]);
@@ -161,7 +162,7 @@ export function Compose({ onPost, replyingTo, onCancelReply, placeholder = "What
             {replyingTo && !isReply && (
                 <div className="compose-reply-target">
                     <div className="compose-reply-info">
-                        Replying to <span className="compose-reply-handle">{formatFullHandle(replyingTo.author.handle)}</span>
+                        Replying to <span className="compose-reply-handle">{replyToHandle}</span>
                     </div>
                     <button type="button" className="compose-reply-cancel" onClick={onCancelReply}>
                         Cancel

src/components/PostCard.tsx

@@ -10,7 +10,8 @@ import { useAuth } from '@/lib/contexts/AuthContext';
 import { useToast } from '@/lib/contexts/ToastContext';
 import { VideoEmbed } from '@/components/VideoEmbed';
 import BlurredVideo from '@/components/BlurredVideo';
-import { formatFullHandle, NODE_DOMAIN } from '@/lib/utils/handle';
+import { useFormattedHandle } from '@/lib/utils/handle';
+import { useDomain } from '@/lib/contexts/ConfigContext';
 import { signedAPI } from '@/lib/api/signed-fetch';
 
 // Component for link preview image that hides on error
@@ -52,6 +53,9 @@ export function PostCard({ post, onLike, onRepost, onComment, onDelete, onHide,
     const [reporting, setReporting] = useState(false);
     const [deleting, setDeleting] = useState(false);
     const [showMenu, setShowMenu] = useState(false);
+    const domain = useDomain();
+    const authorHandle = useFormattedHandle(post.author.handle, post.nodeDomain);
+    const replyToHandle = post.replyTo?.author?.handle ? useFormattedHandle(post.replyTo.author.handle) : '';
 
     // Sync state if post changes (e.g. after a re-render from parent)
     useEffect(() => {
@@ -263,7 +267,7 @@ export function PostCard({ post, onLike, onRepost, onComment, onDelete, onHide,
             return post.author.handle;
         }
         // If this is a swarm post from a DIFFERENT node, append the node domain
-        if (post.nodeDomain && post.nodeDomain !== NODE_DOMAIN) {
+        if (post.nodeDomain && post.nodeDomain !== domain) {
             return `${post.author.handle}@${post.nodeDomain}`;
         }
         // Local user
@@ -403,7 +407,7 @@ export function PostCard({ post, onLike, onRepost, onComment, onDelete, onHide,
                         <Link href={`/u/${profileHandle}`} className="post-handle" onClick={(e) => e.stopPropagation()}>
                             {post.author.displayName || post.author.handle}
                         </Link>
-                        <span className="post-time">{formatFullHandle(post.author.handle, post.nodeDomain)}</span>
+                        <span className="post-time">{authorHandle}</span>
                     </div>
                 </div>
                 <div className="post-content">{renderContent(post.content, post.linkPreviewUrl ?? undefined)}</div>
@@ -467,7 +471,7 @@ export function PostCard({ post, onLike, onRepost, onComment, onDelete, onHide,
                                 </span>
                             )}
                         </div>
-                        <span className="post-time">{formatFullHandle(post.author.handle, post.nodeDomain)} · {formatTime(post.createdAt)}</span>
+                        <span className="post-time">{authorHandle} · {formatTime(post.createdAt)}</span>
                     </div>
                     {currentUser && currentUser.id !== post.author.id && (
                         <div style={{ position: 'relative', marginLeft: 'auto' }}>
@@ -591,7 +595,7 @@ export function PostCard({ post, onLike, onRepost, onComment, onDelete, onHide,
 
                 {effectiveReplyTo && !showThread && (
                     <div className="post-reply-to">
-                        Replying to <Link href={`/u/${effectiveReplyTo.author.handle}`} onClick={(e) => e.stopPropagation()}>{formatFullHandle(effectiveReplyTo.author.handle)}</Link>
+                        Replying to <Link href={`/u/${effectiveReplyTo.author.handle}`} onClick={(e) => e.stopPropagation()}>{replyToHandle}</Link>
                     </div>
                 )}
 
@@ -672,7 +676,7 @@ export function PostCard({ post, onLike, onRepost, onComment, onDelete, onHide,
                         // Allow deleting own remote posts where handle might be username@node_domain
                         (post.author.id.startsWith('swarm:') && (
                             post.author.handle === currentUser.handle ||
-                            post.author.handle === `${currentUser.handle}@${NODE_DOMAIN}`
+                            post.author.handle === `${currentUser.handle}@${domain}`
                         ))
                     )) && (
                             <button className="post-action delete-action" onClick={handleDelete} disabled={deleting} title="Delete post">

src/components/Sidebar.tsx

@@ -6,7 +6,7 @@ import Image from 'next/image';
 import { usePathname, useRouter } from 'next/navigation';
 import { useAuth } from '@/lib/contexts/AuthContext';
 import { HomeIcon, SearchIcon, BellIcon, UserIcon, ShieldIcon, SettingsIcon, BotIcon } from './Icons';
-import { formatFullHandle } from '@/lib/utils/handle';
+import { useFormattedHandle } from '@/lib/utils/handle';
 import { LogOut, Settings2 } from 'lucide-react';
 // import { IdentityUnlockPrompt } from './IdentityUnlockPrompt'; // Moved to LayoutWrapper
 
@@ -18,6 +18,7 @@ export function Sidebar() {
     const [unreadCount, setUnreadCount] = useState(0);
     const [unreadChatCount, setUnreadChatCount] = useState(0);
     const [loggingOut, setLoggingOut] = useState(false);
+    const formattedHandle = user ? useFormattedHandle(user.handle) : '';
 
     useEffect(() => {
         fetch('/api/node')
@@ -188,7 +189,7 @@ export function Sidebar() {
                         </div>
                         <div style={{ minWidth: 0, flex: 1 }}>
                             <div style={{ fontWeight: 600, fontSize: '14px', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>{user.displayName}</div>
-                            <div style={{ color: 'var(--foreground-tertiary)', fontSize: '13px', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>{formatFullHandle(user.handle)}</div>
+                            <div style={{ color: 'var(--foreground-tertiary)', fontSize: '13px', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>{formattedHandle}</div>
                         </div>
                     </div>
 

src/db/schema.ts

@@ -65,8 +65,9 @@ export const users = pgTable('users', {
   movedFrom: text('moved_from'), // Old actor URL if this account migrated here
   migratedAt: timestamp('migrated_at'), // When the migration occurred
   // User-owned S3-compatible storage - required for new users
-  storageProvider: text('storage_provider'), // 's3', 'r2', 'b2', 'wasabi', etc
+  storageProvider: text('storage_provider'), // 's3', 'r2', 'b2', 'wasabi', 'contabo', etc
   storageEndpoint: text('storage_endpoint'), // S3 endpoint URL (optional for AWS)
+  storagePublicBaseUrl: text('storage_public_base_url'), // Public URL for viewing files (required for R2, B2, Contabo)
   storageRegion: text('storage_region'), // Region (e.g., 'us-east-1')
   storageBucket: text('storage_bucket'), // Bucket name
   storageAccessKeyEncrypted: text('storage_access_key_encrypted'), // Encrypted access key

src/lib/auth/index.ts

@@ -139,6 +139,7 @@ export async function registerUser(
     displayName?: string,
     storageProvider?: string,
     storageEndpoint?: string | null,
+    storagePublicBaseUrl?: string | null,
     storageRegion?: string,
     storageBucket?: string,
     storageAccessKey?: string,
@@ -201,6 +202,7 @@ export async function registerUser(
     const avatarUrl = await generateAndUploadAvatarToUserStorage(
         fullHandle,
         storageEndpoint || undefined,
+        storagePublicBaseUrl || undefined,
         storageRegion,
         storageBucket,
         storageAccessKey,
@@ -222,6 +224,7 @@ export async function registerUser(
         privateKeyEncrypted: serializeEncryptedKey(encryptedPrivateKey),
         storageProvider,
         storageEndpoint: storageEndpoint || null,
+        storagePublicBaseUrl: storagePublicBaseUrl || null,
         storageRegion,
         storageBucket,
         storageAccessKeyEncrypted: serializeEncryptedKey(encryptedAccessKey),

src/lib/config.ts

@@ -0,0 +1,33 @@
+let cachedConfig: { domain: string } | null = null;
+let configPromise: Promise<{ domain: string }> | null = null;
+
+export async function getRuntimeConfig() {
+  if (cachedConfig) return cachedConfig;
+  if (configPromise) return configPromise;
+
+  configPromise = fetch('/api/config')
+    .then((res) => res.json())
+    .then((data) => {
+      cachedConfig = {
+        domain: data.domain || 'localhost:3000',
+      };
+      return cachedConfig;
+    })
+    .catch(() => {
+      cachedConfig = {
+        domain: process.env.NEXT_PUBLIC_NODE_DOMAIN || 'localhost:3000',
+      };
+      return cachedConfig;
+    });
+
+  return configPromise;
+}
+
+export function getDomain(): string {
+  return cachedConfig?.domain || process.env.NEXT_PUBLIC_NODE_DOMAIN || 'localhost:3000';
+}
+
+export function clearCachedConfig() {
+  cachedConfig = null;
+  configPromise = null;
+}

src/lib/contexts/ConfigContext.tsx

@@ -0,0 +1,63 @@
+import { createContext, useContext, useEffect, useState, ReactNode } from 'react';
+
+interface RuntimeConfig {
+  domain: string;
+}
+
+interface ConfigContextType {
+  config: RuntimeConfig | null;
+  isLoading: boolean;
+}
+
+const ConfigContext = createContext<ConfigContextType>({
+  config: null,
+  isLoading: true,
+});
+
+export function ConfigProvider({ children }: { children: ReactNode }) {
+  const [config, setConfig] = useState<RuntimeConfig | null>(null);
+  const [isLoading, setIsLoading] = useState(true);
+
+  useEffect(() => {
+    // Fetch runtime config on mount
+    fetch('/api/config')
+      .then((res) => res.json())
+      .then((data) => {
+        setConfig({
+          domain: data.domain || 'localhost:3000',
+        });
+      })
+      .catch(() => {
+        // Fallback to build-time value if fetch fails
+        setConfig({
+          domain: process.env.NEXT_PUBLIC_NODE_DOMAIN || 'localhost:3000',
+        });
+      })
+      .finally(() => {
+        setIsLoading(false);
+      });
+  }, []);
+
+  return (
+    <ConfigContext.Provider value={{ config, isLoading }}>
+      {children}
+    </ConfigContext.Provider>
+  );
+}
+
+export function useRuntimeConfig() {
+  const context = useContext(ConfigContext);
+  if (!context) {
+    throw new Error('useRuntimeConfig must be used within a ConfigProvider');
+  }
+  return context;
+}
+
+export function useDomain(): string {
+  const { config, isLoading } = useRuntimeConfig();
+  // Return runtime domain if loaded, otherwise fall back to build-time value
+  if (isLoading || !config) {
+    return process.env.NEXT_PUBLIC_NODE_DOMAIN || 'localhost:3000';
+  }
+  return config.domain;
+}

src/lib/storage/s3.ts

@@ -65,6 +65,7 @@ export async function uploadToUserStorage(
   mimeType: string,
   provider: StorageProvider,
   endpoint: string | null,
+  publicBaseUrl: string | null,
   region: string,
   bucket: string,
   encryptedAccessKey: string,
@@ -99,8 +100,12 @@ export async function uploadToUserStorage(
 
   // Construct URL based on provider
   let url: string;
-  if (endpoint) {
-    // Custom endpoint (R2, MinIO, etc)
+
+  // Priority: user's publicBaseUrl > construct from endpoint > AWS format
+  if (publicBaseUrl) {
+    url = `${publicBaseUrl.replace(/\/$/, '')}/${key}`;
+  } else if (endpoint) {
+    // Custom endpoint (MinIO, etc)
     url = `${endpoint}/${bucket}/${key}`;
   } else {
     // AWS S3 standard URL
@@ -165,6 +170,7 @@ export async function testS3Credentials(
 export async function generateAndUploadAvatarToUserStorage(
   handle: string,
   endpoint: string | undefined,
+  publicBaseUrl: string | undefined,
   region: string,
   bucket: string,
   accessKey: string,
@@ -202,6 +208,10 @@ export async function generateAndUploadAvatarToUserStorage(
     }));
 
     // 3. Return URL
+    // Priority: user's publicBaseUrl > construct from endpoint > AWS format
+    if (publicBaseUrl) {
+      return `${publicBaseUrl.replace(/\/$/, '')}/${key}`;
+    }
     if (endpoint) {
       return `${endpoint}/${bucket}/${key}`;
     }

src/lib/utils/handle.ts

@@ -1,3 +1,6 @@
+import { useDomain } from '@/lib/contexts/ConfigContext';
+
+// Build-time domain fallback (for SSR/non-React contexts)
 export const NODE_DOMAIN = process.env.NEXT_PUBLIC_NODE_DOMAIN || 'localhost:3000';
 
 /**
@@ -23,3 +26,28 @@ export function formatFullHandle(handle: string, nodeDomain?: string | null): st
     const domain = nodeDomain || NODE_DOMAIN;
     return `@${cleanHandle}@${domain}`;
 }
+
+/**
+ * React hook that formats a handle using the runtime domain config.
+ * Use this in client components instead of formatFullHandle for local handles.
+ * 
+ * @param handle - The user handle (with or without domain)
+ * @param nodeDomain - Optional domain override for swarm posts
+ */
+export function useFormattedHandle(handle: string, nodeDomain?: string | null): string {
+    const runtimeDomain = useDomain();
+    
+    if (!handle) return '';
+
+    // Remove leading @ if present for processing
+    const cleanHandle = handle.startsWith('@') ? handle.slice(1) : handle;
+
+    // Check if it already has a domain (contains @)
+    if (cleanHandle.includes('@')) {
+        return `@${cleanHandle}`;
+    }
+
+    // Use provided domain (for remote posts) or fall back to runtime domain
+    const domain = nodeDomain || runtimeDomain;
+    return `@${cleanHandle}@${domain}`;
+}