fix(notify): use real-time balance for crossing detection and simplify email logic

- Fix cached balance causing threshold crossing to never trigger:
  read real-time balance from billingCacheService instead of stale
  API key auth snapshot
- Remove email="" placeholder concept; all emails are user-managed
- Only send notifications to verified && non-disabled emails
- Frontend: pre-fill user's email in add input when list is empty
- Remove FilterEnabledEmails/IsPrimaryDisabled helpers (no longer needed)

backend/internal/service/balance_notify_service.go

@@ -192,11 +192,10 @@ func (s *BalanceNotifyService) getAccountQuotaNotifyEmails(ctx context.Context)
 	var recipients []string
 	seen := make(map[string]bool)
 	for _, entry := range entries {
-		if entry.Disabled {
+		if entry.Disabled || !entry.Verified {
 			continue
 		}
 		email := strings.TrimSpace(entry.Email)
-		// email="" placeholder is not resolved here; admin should configure actual emails
 		if email == "" {
 			continue
 		}
@@ -219,20 +218,17 @@ func (s *BalanceNotifyService) getSiteName(ctx context.Context) string {
 	return name
 }
 
-// collectBalanceNotifyRecipients collects all non-disabled email recipients for balance notifications.
-// Entries with email="" are resolved to the user's primary email.
+// collectBalanceNotifyRecipients returns verified, non-disabled email recipients.
+// Only emails with verified=true and disabled=false are included.
 func (s *BalanceNotifyService) collectBalanceNotifyRecipients(user *User) []string {
 	var recipients []string
 	seen := make(map[string]bool)
 
 	for _, entry := range user.BalanceNotifyExtraEmails {
-		if entry.Disabled {
+		if entry.Disabled || !entry.Verified {
 			continue
 		}
 		email := strings.TrimSpace(entry.Email)
-		if email == "" {
-			email = user.Email // Resolve primary email placeholder
-		}
 		if email == "" {
 			continue
 		}
@@ -244,11 +240,6 @@ func (s *BalanceNotifyService) collectBalanceNotifyRecipients(user *User) []stri
 		recipients = append(recipients, email)
 	}
 
-	// If no entries exist at all (legacy/empty), fall back to user's primary email
-	if len(user.BalanceNotifyExtraEmails) == 0 && user.Email != "" {
-		recipients = append(recipients, user.Email)
-	}
-
 	return recipients
 }
 

backend/internal/service/gateway_service.go

@@ -7338,9 +7338,15 @@ func finalizePostUsageBilling(p *postUsageBillingParams, deps *billingDeps) {
 
 	deps.deferredService.ScheduleLastUsedUpdate(p.Account.ID)
 
-	// Balance low notification
+	// Balance low notification — use real-time balance from billing cache (not stale snapshot)
 	if !p.IsSubscriptionBill && p.Cost.ActualCost > 0 && p.User != nil && deps.balanceNotifyService != nil {
-		deps.balanceNotifyService.CheckBalanceAfterDeduction(context.Background(), p.User, p.User.Balance, p.Cost.ActualCost)
+		oldBalance := p.User.Balance // fallback to snapshot
+		if deps.billingCacheService != nil {
+			if realBalance, err := deps.billingCacheService.GetUserBalance(context.Background(), p.User.ID); err == nil {
+				oldBalance = realBalance + p.Cost.ActualCost // DB already deducted, reconstruct pre-deduction balance
+			}
+		}
+		deps.balanceNotifyService.CheckBalanceAfterDeduction(context.Background(), p.User, oldBalance, p.Cost.ActualCost)
 	}
 
 	// Account quota notification (use same cost formula as postUsageBilling)

backend/internal/service/notify_email_entry.go

@@ -80,28 +80,3 @@ func MarshalNotifyEmails(entries []NotifyEmailEntry) string {
 	return string(data)
 }
 
-// filterEnabledEmails returns only non-disabled email addresses from entries.
-// Empty email placeholders are skipped (caller should resolve them separately).
-func FilterEnabledEmails(entries []NotifyEmailEntry) []string {
-	var result []string
-	for _, e := range entries {
-		if e.Disabled {
-			continue
-		}
-		email := strings.TrimSpace(e.Email)
-		if email != "" {
-			result = append(result, email)
-		}
-	}
-	return result
-}
-
-// isPrimaryDisabled checks if the primary email placeholder (email="") exists and is disabled.
-func IsPrimaryDisabled(entries []NotifyEmailEntry) bool {
-	for _, e := range entries {
-		if e.Email == "" {
-			return e.Disabled
-		}
-	}
-	return false // No primary placeholder = not disabled
-}

frontend/src/components/user/profile/ProfileBalanceNotifyCard.vue

@@ -48,8 +48,9 @@
         <!-- Email list with toggles -->
         <div>
           <label class="input-label">{{ t('profile.balanceNotify.extraEmails') }}</label>
-          <div class="space-y-2 mb-3">
-            <!-- All email entries (primary placeholder + extra) -->
+
+          <!-- Saved email entries -->
+          <div v-if="emailEntries.length > 0" class="space-y-2 mb-3">
             <div v-for="(entry, idx) in emailEntries" :key="idx"
               class="flex items-center justify-between px-3 py-2 bg-gray-50 dark:bg-dark-700 rounded-lg">
               <div class="flex items-center gap-2 min-w-0 flex-1">
@@ -57,21 +58,19 @@
                   <input type="checkbox" :checked="!entry.disabled" @change="handleEmailToggle(entry)" class="sr-only peer" />
                   <div class="w-9 h-5 bg-gray-200 peer-focus:outline-none rounded-full peer dark:bg-gray-600 peer-checked:after:translate-x-full peer-checked:after:border-white after:content-[''] after:absolute after:top-[2px] after:left-[2px] after:bg-white after:border-gray-300 after:border after:rounded-full after:h-4 after:w-4 after:transition-all dark:after:border-gray-500 peer-checked:bg-primary-600"></div>
                 </label>
-                <span class="text-sm text-gray-700 dark:text-gray-300 truncate">
-                  {{ entry.email === '' ? userEmail : entry.email }}
-                </span>
+                <span class="text-sm text-gray-700 dark:text-gray-300 truncate">{{ entry.email }}</span>
               </div>
               <div class="flex items-center gap-2 shrink-0">
-                <span v-if="entry.email === ''" class="text-xs text-gray-400">{{ t('profile.balanceNotify.primaryEmail') }}</span>
-                <span v-else-if="!entry.verified" class="text-xs text-yellow-500">{{ t('profile.balanceNotify.unverified') }}</span>
-                <button v-if="entry.email !== ''" @click="handleRemoveEmail(entry.email)" class="text-red-500 hover:text-red-700 text-xs">
+                <span v-if="!entry.verified" class="text-xs text-yellow-500">{{ t('profile.balanceNotify.unverified') }}</span>
+                <span v-else class="text-xs text-green-500">{{ t('profile.balanceNotify.verified') }}</span>
+                <button @click="handleRemoveEmail(entry.email)" class="text-red-500 hover:text-red-700 text-xs">
                   {{ t('profile.balanceNotify.removeEmail') }}
                 </button>
               </div>
             </div>
           </div>
 
-          <!-- Pending (unverified) emails -->
+          <!-- Pending (unverified) emails in verification flow -->
           <div v-if="pendingEmails.length > 0" class="space-y-2 mb-3">
             <div v-for="(pe, idx) in pendingEmails" :key="pe.email"
               class="flex items-center gap-2 px-3 py-2 bg-yellow-50 dark:bg-yellow-900/10 rounded-lg border border-yellow-200 dark:border-yellow-800">
@@ -130,7 +129,7 @@
 </template>
 
 <script setup lang="ts">
-import { ref, computed, watch, onUnmounted } from 'vue'
+import { ref, computed, watch, onMounted, onUnmounted } from 'vue'
 import { useI18n } from 'vue-i18n'
 import { useAuthStore } from '@/stores/auth'
 import { useAppStore } from '@/stores/app'
@@ -138,7 +137,7 @@ import { userAPI } from '@/api'
 import { extractApiErrorMessage } from '@/utils/apiError'
 import type { NotifyEmailEntry } from '@/types'
 
-const maxTotalEmails = 3 // primary + 2 extra
+const maxTotalEmails = 3
 
 interface PendingEmail {
   email: string
@@ -177,6 +176,13 @@ watch(() => props.enabled, (val) => { notifyEnabled.value = val })
 watch(() => props.threshold, (val) => { customThreshold.value = val })
 watch(() => props.extraEmails, (val) => { emailEntries.value = [...val] })
 
+// When list is empty on mount, pre-fill the add input with user's email
+onMounted(() => {
+  if (emailEntries.value.length === 0 && props.userEmail) {
+    newEmail.value = props.userEmail
+  }
+})
+
 onUnmounted(() => {
   for (const pe of pendingEmails.value) {
     if (pe.timer) clearInterval(pe.timer)
@@ -221,10 +227,9 @@ async function handleEmailToggle(entry: NotifyEmailEntry) {
 function addPendingEmail() {
   const email = newEmail.value.trim()
   if (!email) return
-  // Check duplicates against existing entries and pending
-  const isDuplicate = emailEntries.value.some(e =>
-    (e.email === '' ? props.userEmail : e.email).toLowerCase() === email.toLowerCase()
-  ) || pendingEmails.value.some(p => p.email.toLowerCase() === email.toLowerCase())
+  // Check duplicates
+  const isDuplicate = emailEntries.value.some(e => e.email.toLowerCase() === email.toLowerCase())
+    || pendingEmails.value.some(p => p.email.toLowerCase() === email.toLowerCase())
   if (isDuplicate) {
     appStore.showError(t('profile.balanceNotify.emailDuplicate'))
     return

frontend/src/i18n/locales/en.ts

@@ -932,6 +932,7 @@ export default {
       emailDuplicate: 'This email already exists',
       maxEmailsReached: 'Maximum number of notification emails reached',
       unverified: 'Unverified',
+      verified: 'Verified',
     }
   },
 

frontend/src/i18n/locales/zh.ts

@@ -936,6 +936,7 @@ export default {
       emailDuplicate: '该邮箱已存在',
       maxEmailsReached: '已达到通知邮箱数量上限',
       unverified: '未验证',
+      verified: '已验证',
     }
   },