diff --git a/apps/desktop-client/src/main/runtime-controller.ts b/apps/desktop-client/src/main/runtime-controller.ts
index 2aa68d2..2f6890c 100644
--- a/apps/desktop-client/src/main/runtime-controller.ts
+++ b/apps/desktop-client/src/main/runtime-controller.ts
@@ -22,6 +22,7 @@ import {
   normalizeAccountPlatformUid,
   sameAccountPlatformUid,
 } from '../shared/account-identity'
+import { normalizeDesktopApiBaseURL } from '../shared/api-base-url'
 import { type PublishAccountIdentity, type PublishAccountProfile } from './account-binder'
 import {
   ensureAccountReady,
@@ -3267,7 +3268,7 @@ function normalizeSession(
   }
 
   return {
-    api_base_url: session.api_base_url.trim() || 'http://localhost:8080',
+    api_base_url: normalizeDesktopApiBaseURL(session.api_base_url),
     mode: session.mode,
     client_token: session.client_token?.trim() || null,
     desktop_client: session.desktop_client ? { ...session.desktop_client } : null,
diff --git a/apps/desktop-client/src/main/transport/api-client.ts b/apps/desktop-client/src/main/transport/api-client.ts
index 5917781..40bc438 100644
--- a/apps/desktop-client/src/main/transport/api-client.ts
+++ b/apps/desktop-client/src/main/transport/api-client.ts
@@ -35,6 +35,7 @@ import {
   startObservedRequest,
 } from '../network-observer'
 import { canUseRendererDevtoolsProxy, rendererDevtoolsFetch } from '../renderer-devtools-proxy'
+import { normalizeDesktopApiBaseURL } from '../../shared/api-base-url'
 
 type TransportAuthState = 'pending' | 'registered' | 'expired'
 type TransportDispatchState = 'idle' | 'connecting' | 'streaming'
@@ -64,7 +65,7 @@ interface MonitoringCancelTaskResponse {
 
 let desktopApiClient: ApiClient | null = null
 let transportSession: DesktopTransportSession = {
-  baseURL: process.env.DESKTOP_API_BASE_URL ?? 'http://localhost:8080',
+  baseURL: normalizeDesktopApiBaseURL(process.env.DESKTOP_API_BASE_URL),
   clientToken: null,
 }
 const ACCOUNT_UPSERT_CACHE_TTL_MS = 5 * 60_000
@@ -364,7 +365,7 @@ export function configureTransport(
 ): ApiClient | null {
   if (!session) {
     transportSession = {
-      baseURL: process.env.DESKTOP_API_BASE_URL ?? 'http://localhost:8080',
+      baseURL: normalizeDesktopApiBaseURL(process.env.DESKTOP_API_BASE_URL),
       clientToken: null,
     }
     transportState.baseURL = transportSession.baseURL
@@ -377,7 +378,7 @@ export function configureTransport(
   }
 
   transportSession = {
-    baseURL: session.api_base_url.trim() || 'http://localhost:8080',
+    baseURL: normalizeDesktopApiBaseURL(session.api_base_url),
     clientToken: session.client_token,
   }
   transportState.baseURL = transportSession.baseURL
diff --git a/apps/desktop-client/src/renderer/composables/useDesktopSession.ts b/apps/desktop-client/src/renderer/composables/useDesktopSession.ts
index 5569513..079ede0 100644
--- a/apps/desktop-client/src/renderer/composables/useDesktopSession.ts
+++ b/apps/desktop-client/src/renderer/composables/useDesktopSession.ts
@@ -13,6 +13,8 @@ import type {
   UserInfo,
 } from '@geo/shared-types'
 
+import { normalizeDesktopApiBaseURL } from '../../shared/api-base-url'
+
 type SessionMode = 'authenticated' | 'preview'
 
 interface DesktopSession {
@@ -35,6 +37,7 @@ const sessionStorageKey = 'geo.desktop.session.v1'
 const apiBaseURLStorageKey = 'geo.desktop.api-base-url'
 export const DEFAULT_API_BASE_URL =
   import.meta.env.VITE_DESKTOP_API_BASE_URL ?? 'https://api.shengxintui.com'
+const normalizedDefaultApiBaseURL = normalizeDesktopApiBaseURL(DEFAULT_API_BASE_URL)
 
 const session = shallowRef<DesktopSession | null>(readStoredSession())
 const apiBaseURL = shallowRef(readStoredApiBaseURL())
@@ -77,18 +80,23 @@ function persistSession(next: DesktopSession | null): void {
 
 function readStoredApiBaseURL(): string {
   if (typeof window === 'undefined') {
-    return DEFAULT_API_BASE_URL
+    return normalizedDefaultApiBaseURL
   }
 
-  return window.localStorage.getItem(apiBaseURLStorageKey) ?? DEFAULT_API_BASE_URL
+  const stored = window.localStorage.getItem(apiBaseURLStorageKey)
+  const normalized = normalizeDesktopApiBaseURL(stored, normalizedDefaultApiBaseURL)
+  if (stored && stored !== normalized) {
+    window.localStorage.setItem(apiBaseURLStorageKey, normalized)
+  }
+  return normalized
 }
 
 function persistApiBaseURL(value: string): void {
-  const trimmed = value.trim() || DEFAULT_API_BASE_URL
-  apiBaseURL.value = trimmed
+  const normalized = normalizeDesktopApiBaseURL(value, normalizedDefaultApiBaseURL)
+  apiBaseURL.value = normalized
 
   if (typeof window !== 'undefined') {
-    window.localStorage.setItem(apiBaseURLStorageKey, trimmed)
+    window.localStorage.setItem(apiBaseURLStorageKey, normalized)
   }
 
   void syncRuntimeSessionToMain()
@@ -528,7 +536,7 @@ async function logout(): Promise<void> {
 if (typeof window !== 'undefined') {
   window.addEventListener('storage', (event) => {
     if (event.key === apiBaseURLStorageKey) {
-      apiBaseURL.value = event.newValue?.trim() || DEFAULT_API_BASE_URL
+      apiBaseURL.value = normalizeDesktopApiBaseURL(event.newValue, normalizedDefaultApiBaseURL)
       void syncRuntimeSessionToMain()
     }
   })
diff --git a/apps/desktop-client/src/shared/api-base-url.ts b/apps/desktop-client/src/shared/api-base-url.ts
new file mode 100644
index 0000000..0692bf9
--- /dev/null
+++ b/apps/desktop-client/src/shared/api-base-url.ts
@@ -0,0 +1,51 @@
+const DEFAULT_LOCAL_API_BASE_URL = 'http://localhost:8080'
+const VITE_DEV_PORT_PATTERN = /^517\d$/
+
+function isLoopbackHost(hostname: string): boolean {
+  const normalized = hostname.toLowerCase()
+  return (
+    normalized === 'localhost' ||
+    normalized === '127.0.0.1' ||
+    normalized === '::1' ||
+    normalized === '[::1]'
+  )
+}
+
+function isViteDevOrigin(url: URL): boolean {
+  return isLoopbackHost(url.hostname) && VITE_DEV_PORT_PATTERN.test(url.port)
+}
+
+function cleanApiBaseURL(url: URL): string {
+  const pathname = url.pathname.replace(/\/+$/, '')
+  const normalizedPath = pathname.replace(/\/api$/i, '')
+
+  url.pathname = normalizedPath || '/'
+  url.search = ''
+  url.hash = ''
+
+  return url.toString().replace(/\/$/, '')
+}
+
+export function normalizeDesktopApiBaseURL(
+  value: string | null | undefined,
+  fallback = DEFAULT_LOCAL_API_BASE_URL,
+): string {
+  const trimmed = String(value ?? '').trim()
+  const candidate = trimmed || fallback
+
+  try {
+    const parsed = new URL(candidate)
+    if (parsed.protocol !== 'http:' && parsed.protocol !== 'https:') {
+      return normalizeDesktopApiBaseURL(fallback, DEFAULT_LOCAL_API_BASE_URL)
+    }
+    if (isViteDevOrigin(parsed)) {
+      return DEFAULT_LOCAL_API_BASE_URL
+    }
+    return cleanApiBaseURL(parsed)
+  } catch {
+    if (candidate === fallback) {
+      return DEFAULT_LOCAL_API_BASE_URL
+    }
+    return normalizeDesktopApiBaseURL(fallback, DEFAULT_LOCAL_API_BASE_URL)
+  }
+}