diff --git a/app/(main)/[locale]/auth/callback/page.tsx b/app/(main)/[locale]/auth/callback/page.tsx
index a469c194..a0845972 100644
--- a/app/(main)/[locale]/auth/callback/page.tsx
+++ b/app/(main)/[locale]/auth/callback/page.tsx
@@ -4,7 +4,7 @@ import { Suspense, useEffect, useState } from "react";
 import { useRouter, useSearchParams } from "next/navigation";
 import { useTranslations } from "next-intl";
 import { useAuthStore } from "@/stores/auth-store";
-import { getPathPrefix } from "@/lib/browser-navigation";
+import { apiFetch, getPathPrefix } from "@/lib/browser-navigation";
 import { Loader2, AlertCircle } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { useParams } from "next/navigation";
@@ -96,7 +96,7 @@ function OAuthCallbackInner() {
         // the refresh-token cookie write for the same reason.
         (async () => {
           try {
-            const res = await fetch("/api/auth/sso/complete", {
+            const res = await apiFetch("/api/auth/sso/complete", {
               method: "POST",
               headers: { "Content-Type": "application/json" },
               credentials: "include",
diff --git a/app/(main)/[locale]/pro/page.tsx b/app/(main)/[locale]/pro/page.tsx
index c8b00f14..1d1005f0 100644
--- a/app/(main)/[locale]/pro/page.tsx
+++ b/app/(main)/[locale]/pro/page.tsx
@@ -16,6 +16,7 @@ import { PaneSizeContext } from "@/hooks/use-pane-size";
 import { ProTabBar, PRO_TAB_DRAG_MIME } from "@/components/pro/pro-tab-bar";
 import { useProTabStore, type ProTab, type ProTabKind, type ProPaneId } from "@/stores/pro-tab-store";
 import { cn } from "@/lib/utils";
+import { getPathPrefix } from "@/lib/browser-navigation";
 
 import MailPage from "@/app/(main)/[locale]/page";
 import CalendarPage from "@/app/(main)/[locale]/calendar/page";
@@ -172,7 +173,7 @@ export default function ProHome() {
     // enabled it. If either precondition stops holding, hand the user back
     // to the standard shell.
     if (isMobile || isTablet || !proInterface) {
-      window.location.replace("/");
+      window.location.replace(`${getPathPrefix()}/`);
     }
   }, [initialCheckDone, isMobile, isTablet, proInterface]);
 
diff --git a/app/(main)/setup/page.tsx b/app/(main)/setup/page.tsx
index 64e9cad6..686bb202 100644
--- a/app/(main)/setup/page.tsx
+++ b/app/(main)/setup/page.tsx
@@ -3,7 +3,7 @@
 import { useEffect, useState, type FormEvent, type ReactNode } from 'react';
 import { useRouter, useSearchParams } from 'next/navigation';
 import { CheckCircle2, AlertTriangle, AlertCircle, Server, ShieldCheck, KeyRound, FileText, Palette, Lock, ShieldAlert } from 'lucide-react';
-import { apiFetch } from '@/lib/browser-navigation';
+import { apiFetch, getPathPrefix } from '@/lib/browser-navigation';
 
 type State = 'bootstrap' | 'configured' | 'env-managed';
 
@@ -258,7 +258,7 @@ export default function SetupWizardPage() {
                 // edge cases that swallow client-side replaces after the
                 // setupComplete flag flips.
                 setTimeout(() => {
-                  window.location.assign('/admin/login');
+                  window.location.assign(`${getPathPrefix()}/admin/login`);
                 }, 1500);
               }}
             />
@@ -340,13 +340,13 @@ function CompletedScreen() {
       </div>
       <div className="mt-6 space-y-2">
         <a
-          href="/admin/login"
+          href={`${getPathPrefix()}/admin/login`}
           className="block w-full rounded-md bg-primary text-primary-foreground text-center px-4 py-2.5 text-sm font-medium hover:bg-primary/90"
         >
           Sign in to admin dashboard
         </a>
         <a
-          href="/"
+          href={`${getPathPrefix()}/`}
           className="block w-full rounded-md border border-border text-center px-4 py-2.5 text-sm font-medium hover:bg-muted"
         >
           Open webmail login
@@ -422,13 +422,13 @@ function AlreadyConfiguredScreen() {
       </div>
       <div className="mt-6 space-y-2">
         <a
-          href="/admin/login"
+          href={`${getPathPrefix()}/admin/login`}
           className="block w-full rounded-md bg-primary text-primary-foreground text-center px-4 py-2.5 text-sm font-medium hover:bg-primary/90"
         >
           Sign in to admin dashboard
         </a>
         <a
-          href="/"
+          href={`${getPathPrefix()}/`}
           className="block w-full rounded-md border border-border text-center px-4 py-2.5 text-sm font-medium hover:bg-muted"
         >
           Open webmail login
diff --git a/components/layout/navigation-rail.tsx b/components/layout/navigation-rail.tsx
index 8a8b58f9..56a721d9 100644
--- a/components/layout/navigation-rail.tsx
+++ b/components/layout/navigation-rail.tsx
@@ -21,7 +21,7 @@ import { getMaxAccounts } from "@/lib/account-utils";
 import { cn, formatFileSize } from "@/lib/utils";
 import { PluginSlot } from "@/components/plugins/plugin-slot";
 import { KeyboardShortcutsModal } from "@/components/keyboard-shortcuts-modal";
-import { apiFetch } from "@/lib/browser-navigation";
+import { apiFetch, getPathPrefix } from "@/lib/browser-navigation";
 import { Avatar } from "@/components/ui/avatar";
 
 interface NavItem {
@@ -385,7 +385,7 @@ export function NavigationRail({
         {/* Admin (Stalwart admins) - hard nav because /admin lives outside the [locale] tree */}
         {isStalwartAdmin && (
           <a
-            href="/admin"
+            href={`${getPathPrefix()}/admin`}
             className={cn(
               "flex flex-col items-center justify-center gap-1 py-2 px-1 min-h-[44px] grow shrink-0 basis-[64px]",
               "transition-colors duration-150",
@@ -572,7 +572,7 @@ export function NavigationRail({
       <div className="mt-auto flex flex-col items-center gap-2 pb-3 px-1">
         {isStalwartAdmin && (
           <a
-            href="/admin"
+            href={`${getPathPrefix()}/admin`}
             className="flex items-center justify-center w-10 h-10 rounded-md transition-colors text-muted-foreground hover:text-foreground hover:bg-muted relative"
             title={t("admin") || "Admin"}
           >
diff --git a/components/settings/about-data-settings.tsx b/components/settings/about-data-settings.tsx
index 6488d1cb..26be560c 100644
--- a/components/settings/about-data-settings.tsx
+++ b/components/settings/about-data-settings.tsx
@@ -10,6 +10,7 @@ import { usePolicyStore } from '@/stores/policy-store';
 import { useUpdateStore } from '@/stores/update-store';
 import { ExternalLink } from 'lucide-react';
 import { cn } from '@/lib/utils';
+import { getPathPrefix } from '@/lib/browser-navigation';
 import { SpamSiegeGame } from './spam-siege-game';
 
 const APP_VERSION = process.env.NEXT_PUBLIC_APP_VERSION || "0.0.0";
@@ -123,12 +124,12 @@ export function AboutDataSettings() {
           <button onClick={handleLogoClick} className="flex items-center gap-4 flex-1 text-left focus:outline-none group/about cursor-pointer" aria-label="About">
             <div className="shrink-0">
               <img
-                src="/branding/Bulwark_Logo_Color.svg"
+                src={`${getPathPrefix()}/branding/Bulwark_Logo_Color.svg`}
                 alt="Bulwark"
                 className="w-12 h-12 object-contain dark:hidden group-hover/about:scale-105 group-active/about:scale-95 transition-transform"
               />
               <img
-                src="/branding/Bulwark_Logo_White.svg"
+                src={`${getPathPrefix()}/branding/Bulwark_Logo_White.svg`}
                 alt="Bulwark"
                 className="w-12 h-12 object-contain hidden dark:block group-hover/about:scale-105 group-active/about:scale-95 transition-transform"
               />
diff --git a/lib/plugin-sandbox/bundle-signing.ts b/lib/plugin-sandbox/bundle-signing.ts
index 451edc42..f69f6f7c 100644
--- a/lib/plugin-sandbox/bundle-signing.ts
+++ b/lib/plugin-sandbox/bundle-signing.ts
@@ -10,6 +10,8 @@
 // installing their own code. Verification kicks in for server-managed
 // bundles only (the `managed: true` flag on `InstalledPlugin`).
 
+import { apiFetch } from '@/lib/browser-navigation';
+
 let cachedPubKey: CryptoKey | null = null;
 let pubKeyPromise: Promise<CryptoKey | null> | null = null;
 
@@ -26,7 +28,7 @@ async function importEd25519PublicKey(raw: Uint8Array): Promise<CryptoKey | null
 
 async function fetchPublicKey(): Promise<CryptoKey | null> {
   try {
-    const res = await fetch('/api/plugin-signing-pubkey', { credentials: 'same-origin' });
+    const res = await apiFetch('/api/plugin-signing-pubkey', { credentials: 'same-origin' });
     if (!res.ok) return null;
     const data = await res.json() as { algorithm?: string; publicKey?: string };
     if (data.algorithm !== 'ed25519' || typeof data.publicKey !== 'string') return null;