diff --git a/backend/igny8_core/api/account_views.py b/backend/igny8_core/api/account_views.py
index 512d0943..2b077e17 100644
--- a/backend/igny8_core/api/account_views.py
+++ b/backend/igny8_core/api/account_views.py
@@ -10,6 +10,7 @@ from django.contrib.auth import get_user_model
 from django.db.models import Q, Count, Sum
 from django.utils import timezone
 from datetime import timedelta
+from drf_spectacular.utils import extend_schema, extend_schema_view
 
 from igny8_core.auth.models import Account
 from igny8_core.business.billing.models import CreditTransaction
@@ -17,6 +18,10 @@ from igny8_core.business.billing.models import CreditTransaction
 User = get_user_model()
 
 
+@extend_schema_view(
+    retrieve=extend_schema(tags=['Account']),
+    partial_update=extend_schema(tags=['Account']),
+)
 class AccountSettingsViewSet(viewsets.ViewSet):
     """Account settings management"""
     permission_classes = [IsAuthenticated]
@@ -77,6 +82,11 @@ class AccountSettingsViewSet(viewsets.ViewSet):
         })
 
 
+@extend_schema_view(
+    list=extend_schema(tags=['Account']),
+    create=extend_schema(tags=['Account']),
+    destroy=extend_schema(tags=['Account']),
+)
 class TeamManagementViewSet(viewsets.ViewSet):
     """Team members management"""
     permission_classes = [IsAuthenticated]
@@ -166,6 +176,9 @@ class TeamManagementViewSet(viewsets.ViewSet):
             )
 
 
+@extend_schema_view(
+    overview=extend_schema(tags=['Account']),
+)
 class UsageAnalyticsViewSet(viewsets.ViewSet):
     """Usage analytics and statistics"""
     permission_classes = [IsAuthenticated]
diff --git a/backend/igny8_core/api/schema_extensions.py b/backend/igny8_core/api/schema_extensions.py
index 2cddf15d..67c8c81b 100644
--- a/backend/igny8_core/api/schema_extensions.py
+++ b/backend/igny8_core/api/schema_extensions.py
@@ -8,7 +8,20 @@ from drf_spectacular.utils import extend_schema, OpenApiResponse
 from rest_framework import status
 
 # Explicit tags we want to keep (from SPECTACULAR_SETTINGS)
-EXPLICIT_TAGS = {'Authentication', 'Planner', 'Writer', 'System', 'Billing'}
+EXPLICIT_TAGS = {
+    'Authentication',
+    'Planner',
+    'Writer',
+    'System',
+    'Billing',
+    'Account',
+    'Automation',
+    'Linker',
+    'Optimizer',
+    'Publisher',
+    'Integration',
+    'Admin Billing',
+}
 
 
 def postprocess_schema_filter_tags(result, generator, request, public):
@@ -41,6 +54,20 @@ def postprocess_schema_filter_tags(result, generator, request, public):
                             filtered_tags = ['System']
                         elif '/billing/' in path or '/api/v1/billing/' in path:
                             filtered_tags = ['Billing']
+                        elif '/account/' in path or '/api/v1/account/' in path:
+                            filtered_tags = ['Account']
+                        elif '/automation/' in path or '/api/v1/automation/' in path:
+                            filtered_tags = ['Automation']
+                        elif '/linker/' in path or '/api/v1/linker/' in path:
+                            filtered_tags = ['Linker']
+                        elif '/optimizer/' in path or '/api/v1/optimizer/' in path:
+                            filtered_tags = ['Optimizer']
+                        elif '/publisher/' in path or '/api/v1/publisher/' in path:
+                            filtered_tags = ['Publisher']
+                        elif '/integration/' in path or '/api/v1/integration/' in path:
+                            filtered_tags = ['Integration']
+                        elif '/admin/' in path or '/api/v1/admin/' in path:
+                            filtered_tags = ['Admin Billing']
                     
                     operation['tags'] = filtered_tags
     
diff --git a/backend/igny8_core/business/automation/views.py b/backend/igny8_core/business/automation/views.py
index 04a4097c..18197113 100644
--- a/backend/igny8_core/business/automation/views.py
+++ b/backend/igny8_core/business/automation/views.py
@@ -8,6 +8,7 @@ from rest_framework.response import Response
 from rest_framework.permissions import IsAuthenticated
 from django.shortcuts import get_object_or_404
 from django.utils import timezone
+from drf_spectacular.utils import extend_schema
 
 from igny8_core.business.automation.models import AutomationConfig, AutomationRun
 from igny8_core.business.automation.services import AutomationService
@@ -30,6 +31,7 @@ class AutomationViewSet(viewsets.ViewSet):
         site = get_object_or_404(Site, id=site_id, account=request.user.account)
         return site, None
     
+    @extend_schema(tags=['Automation'])
     @action(detail=False, methods=['get'])
     def config(self, request):
         """
@@ -68,6 +70,7 @@ class AutomationViewSet(viewsets.ViewSet):
             'next_run_at': config.next_run_at,
         })
     
+    @extend_schema(tags=['Automation'])
     @action(detail=False, methods=['put'])
     def update_config(self, request):
         """
@@ -142,6 +145,7 @@ class AutomationViewSet(viewsets.ViewSet):
             'next_run_at': config.next_run_at,
         })
     
+    @extend_schema(tags=['Automation'])
     @action(detail=False, methods=['post'])
     def run_now(self, request):
         """
@@ -175,6 +179,7 @@ class AutomationViewSet(viewsets.ViewSet):
                 status=status.HTTP_500_INTERNAL_SERVER_ERROR
             )
     
+    @extend_schema(tags=['Automation'])
     @action(detail=False, methods=['get'])
     def current_run(self, request):
         """
@@ -211,6 +216,7 @@ class AutomationViewSet(viewsets.ViewSet):
             }
         })
     
+    @extend_schema(tags=['Automation'])
     @action(detail=False, methods=['post'])
     def pause(self, request):
         """
@@ -234,6 +240,7 @@ class AutomationViewSet(viewsets.ViewSet):
                 status=status.HTTP_404_NOT_FOUND
             )
     
+    @extend_schema(tags=['Automation'])
     @action(detail=False, methods=['post'])
     def resume(self, request):
         """
@@ -262,6 +269,7 @@ class AutomationViewSet(viewsets.ViewSet):
                 status=status.HTTP_404_NOT_FOUND
             )
     
+    @extend_schema(tags=['Automation'])
     @action(detail=False, methods=['get'])
     def history(self, request):
         """
@@ -291,6 +299,7 @@ class AutomationViewSet(viewsets.ViewSet):
             ]
         })
     
+    @extend_schema(tags=['Automation'])
     @action(detail=False, methods=['get'])
     def logs(self, request):
         """
@@ -323,6 +332,7 @@ class AutomationViewSet(viewsets.ViewSet):
                 status=status.HTTP_404_NOT_FOUND
             )
     
+    @extend_schema(tags=['Automation'])
     @action(detail=False, methods=['get'])
     def estimate(self, request):
         """
@@ -342,6 +352,7 @@ class AutomationViewSet(viewsets.ViewSet):
             'sufficient': site.account.credits >= (estimated_credits * 1.2)
         })
     
+    @extend_schema(tags=['Automation'])
     @action(detail=False, methods=['get'])
     def pipeline_overview(self, request):
         """
@@ -504,6 +515,7 @@ class AutomationViewSet(viewsets.ViewSet):
             ]
         })
 
+    @extend_schema(tags=['Automation'])
     @action(detail=False, methods=['get'], url_path='current_processing')
     def current_processing(self, request):
         """
@@ -547,6 +559,7 @@ class AutomationViewSet(viewsets.ViewSet):
                 status=status.HTTP_500_INTERNAL_SERVER_ERROR
             )
 
+    @extend_schema(tags=['Automation'])
     @action(detail=False, methods=['post'], url_path='pause')
     def pause_automation(self, request):
         """
@@ -596,6 +609,7 @@ class AutomationViewSet(viewsets.ViewSet):
                 status=status.HTTP_500_INTERNAL_SERVER_ERROR
             )
 
+    @extend_schema(tags=['Automation'])
     @action(detail=False, methods=['post'], url_path='resume')
     def resume_automation(self, request):
         """
@@ -649,6 +663,7 @@ class AutomationViewSet(viewsets.ViewSet):
                 status=status.HTTP_500_INTERNAL_SERVER_ERROR
             )
 
+    @extend_schema(tags=['Automation'])
     @action(detail=False, methods=['post'], url_path='cancel')
     def cancel_automation(self, request):
         """
diff --git a/backend/igny8_core/business/billing/urls.py b/backend/igny8_core/business/billing/urls.py
index d3fd7690..3818d747 100644
--- a/backend/igny8_core/business/billing/urls.py
+++ b/backend/igny8_core/business/billing/urls.py
@@ -11,14 +11,21 @@ from .views import (
     AdminBillingViewSet,
     AccountPaymentMethodViewSet,
 )
+from igny8_core.modules.billing.views import (
+    CreditBalanceViewSet,
+    CreditUsageViewSet,
+)
 
 router = DefaultRouter()
 router.register(r'invoices', InvoiceViewSet, basename='invoice')
 router.register(r'payments', PaymentViewSet, basename='payment')
 router.register(r'credit-packages', CreditPackageViewSet, basename='credit-package')
 router.register(r'transactions', CreditTransactionViewSet, basename='transaction')
-router.register(r'admin', AdminBillingViewSet, basename='admin-billing')
 router.register(r'payment-methods', AccountPaymentMethodViewSet, basename='payment-method')
+# Canonical credits endpoints (unified billing)
+router.register(r'credits/balance', CreditBalanceViewSet, basename='credit-balance')
+router.register(r'credits/usage', CreditUsageViewSet, basename='credit-usage')
+router.register(r'credits/transactions', CreditTransactionViewSet, basename='credit-transactions')
 
 urlpatterns = [
     # Country/config-driven available methods (legacy alias)
diff --git a/backend/igny8_core/business/billing/views.py b/backend/igny8_core/business/billing/views.py
index fcadda90..73dcb4de 100644
--- a/backend/igny8_core/business/billing/views.py
+++ b/backend/igny8_core/business/billing/views.py
@@ -9,6 +9,7 @@ from rest_framework.permissions import IsAuthenticated
 from django.http import HttpResponse
 from django.shortcuts import get_object_or_404
 from django.db import models
+from drf_spectacular.utils import extend_schema, extend_schema_view
 
 from .models import (
     Invoice,
@@ -366,6 +367,14 @@ class CreditTransactionViewSet(viewsets.ViewSet):
         })
 
 
+@extend_schema_view(
+    invoices=extend_schema(tags=['Admin Billing']),
+    payments=extend_schema(tags=['Admin Billing']),
+    pending_payments=extend_schema(tags=['Admin Billing']),
+    approve_payment=extend_schema(tags=['Admin Billing']),
+    reject_payment=extend_schema(tags=['Admin Billing']),
+    stats=extend_schema(tags=['Admin Billing']),
+)
 class AdminBillingViewSet(viewsets.ViewSet):
     """Admin billing management"""
     permission_classes = [IsAuthenticated]
diff --git a/backend/igny8_core/modules/billing/admin_urls.py b/backend/igny8_core/modules/billing/admin_urls.py
index 9efd28e2..6ecf129f 100644
--- a/backend/igny8_core/modules/billing/admin_urls.py
+++ b/backend/igny8_core/modules/billing/admin_urls.py
@@ -1,6 +1,10 @@
 from django.urls import path
 from rest_framework.routers import DefaultRouter
+
 from .views import AdminBillingViewSet
+from igny8_core.business.billing.views import (
+    AdminBillingViewSet as BillingAdminViewSet,
+)
 
 router = DefaultRouter()
 
@@ -9,6 +13,12 @@ urlpatterns = [
     path('users/', AdminBillingViewSet.as_view({'get': 'list_users'}), name='admin-users-list'),
     path('users/<int:user_id>/adjust-credits/', AdminBillingViewSet.as_view({'post': 'adjust_credits'}), name='admin-adjust-credits'),
     path('credit-costs/', AdminBillingViewSet.as_view({'get': 'list_credit_costs', 'post': 'update_credit_costs'}), name='admin-credit-costs'),
+    # Unified admin billing endpoints (alias legacy /billing/admin/* under /admin/billing/*)
+    path('billing/invoices/', BillingAdminViewSet.as_view({'get': 'invoices'}), name='admin-billing-invoices'),
+    path('billing/payments/', BillingAdminViewSet.as_view({'get': 'payments'}), name='admin-billing-payments'),
+    path('billing/pending_payments/', BillingAdminViewSet.as_view({'get': 'pending_payments'}), name='admin-billing-pending-payments'),
+    path('billing/<int:pk>/approve_payment/', BillingAdminViewSet.as_view({'post': 'approve_payment'}), name='admin-billing-approve-payment'),
+    path('billing/<int:pk>/reject_payment/', BillingAdminViewSet.as_view({'post': 'reject_payment'}), name='admin-billing-reject-payment'),
 ]
 
 urlpatterns += router.urls
diff --git a/backend/igny8_core/modules/billing/urls.py b/backend/igny8_core/modules/billing/urls.py
index 3665f058..cb0aeda0 100644
--- a/backend/igny8_core/modules/billing/urls.py
+++ b/backend/igny8_core/modules/billing/urls.py
@@ -20,6 +20,9 @@ urlpatterns = [
     path('', include(router.urls)),
     # User-facing billing overview
     path('account_balance/', BillingOverviewViewSet.as_view({'get': 'account_balance'}), name='account-balance'),
+    # Canonical credit balance endpoint
+    path('credits/balance/', CreditBalanceViewSet.as_view({'get': 'list'}), name='credit-balance-canonical'),
+    # Explicit list endpoints
     path('transactions/', CreditTransactionViewSet.as_view({'get': 'list'}), name='transactions'),
     path('usage/', CreditUsageViewSet.as_view({'get': 'list'}), name='usage'),
     # Admin billing endpoints
diff --git a/backend/igny8_core/modules/billing/views.py b/backend/igny8_core/modules/billing/views.py
index 1d3f866a..acaa2ea2 100644
--- a/backend/igny8_core/modules/billing/views.py
+++ b/backend/igny8_core/modules/billing/views.py
@@ -26,7 +26,7 @@ from .exceptions import InsufficientCreditsError
 
 
 @extend_schema_view(
-    list=extend_schema(tags=['Billing']),
+    list=extend_schema(tags=['Billing'], summary='Get credit balance'),
 )
 class CreditBalanceViewSet(viewsets.ViewSet):
     """
@@ -38,8 +38,7 @@ class CreditBalanceViewSet(viewsets.ViewSet):
     throttle_scope = 'billing'
     throttle_classes = [DebugScopedRateThrottle]
     
-    @action(detail=False, methods=['get'])
-    def balance(self, request):
+    def list(self, request):
         """Get current credit balance and usage"""
         account = getattr(request, 'account', None)
         if not account:
@@ -125,6 +124,7 @@ class CreditUsageViewSet(AccountModelViewSet):
         
         return queryset.order_by('-created_at')
     
+    @extend_schema(tags=['Billing'], summary='Get usage summary')
     @action(detail=False, methods=['get'])
     def summary(self, request):
         """Get usage summary for date range"""
@@ -214,6 +214,7 @@ class CreditUsageViewSet(AccountModelViewSet):
         serializer = UsageSummarySerializer(data)
         return success_response(data=serializer.data, request=request)
     
+    @extend_schema(tags=['Billing'], summary='Get usage limits')
     @action(detail=False, methods=['get'], url_path='limits', url_name='limits')
     def limits(self, request):
         """
@@ -434,6 +435,13 @@ class BillingOverviewViewSet(viewsets.ViewSet):
         return Response(data)
 
 
+@extend_schema_view(
+    stats=extend_schema(tags=['Admin Billing'], summary='Admin billing stats'),
+    list_users=extend_schema(tags=['Admin Billing'], summary='List users with credit info'),
+    adjust_credits=extend_schema(tags=['Admin Billing'], summary='Adjust user credits'),
+    list_credit_costs=extend_schema(tags=['Admin Billing'], summary='List credit cost configurations'),
+    update_credit_costs=extend_schema(tags=['Admin Billing'], summary='Update credit cost configurations'),
+)
 class AdminBillingViewSet(viewsets.ViewSet):
     """Admin-only billing management API"""
     permission_classes = [IsAuthenticatedAndActive, permissions.IsAdminUser]
diff --git a/backend/igny8_core/modules/integration/views.py b/backend/igny8_core/modules/integration/views.py
index 10b6f12e..586c6226 100644
--- a/backend/igny8_core/modules/integration/views.py
+++ b/backend/igny8_core/modules/integration/views.py
@@ -6,6 +6,7 @@ from rest_framework import status
 from rest_framework.decorators import action
 from rest_framework.response import Response
 from django.utils import timezone
+from drf_spectacular.utils import extend_schema, extend_schema_view
 
 from igny8_core.api.base import SiteSectorModelViewSet
 from igny8_core.api.permissions import IsAuthenticatedAndActive, IsEditorOrAbove
@@ -21,6 +22,14 @@ import logging
 logger = logging.getLogger(__name__)
 
 
+@extend_schema_view(
+    list=extend_schema(tags=['Integration']),
+    create=extend_schema(tags=['Integration']),
+    retrieve=extend_schema(tags=['Integration']),
+    update=extend_schema(tags=['Integration']),
+    partial_update=extend_schema(tags=['Integration']),
+    destroy=extend_schema(tags=['Integration']),
+)
 class IntegrationViewSet(SiteSectorModelViewSet):
     """
     ViewSet for SiteIntegration model.
@@ -88,6 +97,7 @@ class IntegrationViewSet(SiteSectorModelViewSet):
         
         return SiteIntegrationSerializer
     
+    @extend_schema(tags=['Integration'])
     @action(detail=True, methods=['post'])
     def test_connection(self, request, pk=None):
         """
@@ -118,6 +128,7 @@ class IntegrationViewSet(SiteSectorModelViewSet):
         def allow_request(self, request, view):
             return True
 
+    @extend_schema(tags=['Integration'])
     @action(detail=False, methods=['post'], url_path='test-connection', 
             permission_classes=[AllowAny], throttle_classes=[NoThrottle])
     def test_connection_collection(self, request):
@@ -221,6 +232,7 @@ class IntegrationViewSet(SiteSectorModelViewSet):
                 logger.info(f"[IntegrationViewSet] Deleted integration {integration.id} due to failed connection test")
             return error_response(result.get('message', 'Connection test failed'), None, status.HTTP_400_BAD_REQUEST, request)
     
+    @extend_schema(tags=['Integration'])
     @action(detail=True, methods=['post'])
     def sync(self, request, pk=None):
         """
@@ -252,6 +264,7 @@ class IntegrationViewSet(SiteSectorModelViewSet):
         response_status = status.HTTP_200_OK if result.get('success') else status.HTTP_400_BAD_REQUEST
         return success_response(result, request=request, status_code=response_status)
     
+    @extend_schema(tags=['Integration'])
     @action(detail=True, methods=['get'])
     def sync_status(self, request, pk=None):
         """
diff --git a/backend/igny8_core/modules/publisher/views.py b/backend/igny8_core/modules/publisher/views.py
index f2bb3f56..1968535a 100644
--- a/backend/igny8_core/modules/publisher/views.py
+++ b/backend/igny8_core/modules/publisher/views.py
@@ -11,6 +11,7 @@ from rest_framework.response import Response
 from rest_framework.views import APIView
 from django.views.decorators.csrf import csrf_exempt
 from django.utils.decorators import method_decorator
+from drf_spectacular.utils import extend_schema, extend_schema_view
 
 from igny8_core.api.base import SiteSectorModelViewSet
 from igny8_core.api.permissions import IsAuthenticatedAndActive, IsEditorOrAbove
@@ -20,6 +21,14 @@ from igny8_core.business.publishing.models import PublishingRecord, DeploymentRe
 from igny8_core.business.publishing.services.publisher_service import PublisherService
 
 
+@extend_schema_view(
+    list=extend_schema(tags=['Publisher']),
+    create=extend_schema(tags=['Publisher']),
+    retrieve=extend_schema(tags=['Publisher']),
+    update=extend_schema(tags=['Publisher']),
+    partial_update=extend_schema(tags=['Publisher']),
+    destroy=extend_schema(tags=['Publisher']),
+)
 class PublishingRecordViewSet(SiteSectorModelViewSet):
     """
     ViewSet for PublishingRecord model.
@@ -41,6 +50,14 @@ class PublishingRecordViewSet(SiteSectorModelViewSet):
         return PublishingRecordSerializer
 
 
+@extend_schema_view(
+    list=extend_schema(tags=['Publisher']),
+    create=extend_schema(tags=['Publisher']),
+    retrieve=extend_schema(tags=['Publisher']),
+    update=extend_schema(tags=['Publisher']),
+    partial_update=extend_schema(tags=['Publisher']),
+    destroy=extend_schema(tags=['Publisher']),
+)
 class DeploymentRecordViewSet(SiteSectorModelViewSet):
     """
     ViewSet for DeploymentRecord model.
@@ -63,6 +80,7 @@ class DeploymentRecordViewSet(SiteSectorModelViewSet):
         return DeploymentRecordSerializer
 
 
+@extend_schema_view()
 class PublisherViewSet(viewsets.ViewSet):
     """
     Publisher actions for publishing content.
@@ -76,6 +94,7 @@ class PublisherViewSet(viewsets.ViewSet):
         super().__init__(**kwargs)
         self.publisher_service = PublisherService()
     
+    @extend_schema(tags=['Publisher'])
     @action(detail=False, methods=['post'], url_path='publish')
     def publish(self, request):
         """
diff --git a/backend/igny8_core/modules/writer/views.py b/backend/igny8_core/modules/writer/views.py
index f184fb57..76cba558 100644
--- a/backend/igny8_core/modules/writer/views.py
+++ b/backend/igny8_core/modules/writer/views.py
@@ -1580,12 +1580,12 @@ class ContentViewSet(SiteSectorModelViewSet):
 
 
 @extend_schema_view(
-    list=extend_schema(tags=['Writer - Taxonomies']),
-    create=extend_schema(tags=['Writer - Taxonomies']),
-    retrieve=extend_schema(tags=['Writer - Taxonomies']),
-    update=extend_schema(tags=['Writer - Taxonomies']),
-    partial_update=extend_schema(tags=['Writer - Taxonomies']),
-    destroy=extend_schema(tags=['Writer - Taxonomies']),
+    list=extend_schema(tags=['Writer']),
+    create=extend_schema(tags=['Writer']),
+    retrieve=extend_schema(tags=['Writer']),
+    update=extend_schema(tags=['Writer']),
+    partial_update=extend_schema(tags=['Writer']),
+    destroy=extend_schema(tags=['Writer']),
 )
 class ContentTaxonomyViewSet(SiteSectorModelViewSet):
     """
diff --git a/backend/igny8_core/settings.py b/backend/igny8_core/settings.py
index 21c764f8..755cfe3d 100644
--- a/backend/igny8_core/settings.py
+++ b/backend/igny8_core/settings.py
@@ -352,12 +352,32 @@ SPECTACULAR_SETTINGS = {
     # Tag configuration - prevent auto-generation and use explicit tags
     'TAGS': [
         {'name': 'Authentication', 'description': 'User authentication and registration'},
+        {'name': 'Account', 'description': 'Account settings, team, and usage analytics'},
+        {'name': 'Integration', 'description': 'Site integrations and sync'},
+        {'name': 'System', 'description': 'Settings, prompts, and integrations'},
+        {'name': 'Admin Billing', 'description': 'Admin-only billing management'},
+        {'name': 'Billing', 'description': 'Credits, usage, and transactions'},
         {'name': 'Planner', 'description': 'Keywords, clusters, and content ideas'},
         {'name': 'Writer', 'description': 'Tasks, content, and images'},
-        {'name': 'System', 'description': 'Settings, prompts, and integrations'},
-        {'name': 'Billing', 'description': 'Credits, usage, and transactions'},
+        {'name': 'Automation', 'description': 'Automation configuration and runs'},
+        {'name': 'Linker', 'description': 'Internal linking operations'},
+        {'name': 'Optimizer', 'description': 'Content optimization operations'},
+        {'name': 'Publisher', 'description': 'Publishing records and deployments'},
+    ],
+    'TAGS_ORDER': [
+        'Authentication',
+        'Account',
+        'Integration',
+        'System',
+        'Admin Billing',
+        'Billing',
+        'Planner',
+        'Writer',
+        'Automation',
+        'Linker',
+        'Optimizer',
+        'Publisher',
     ],
-    'TAGS_ORDER': ['Authentication', 'Planner', 'Writer', 'System', 'Billing'],
     # Postprocessing hook to filter out auto-generated tags
     'POSTPROCESSING_HOOKS': ['igny8_core.api.schema_extensions.postprocess_schema_filter_tags'],
     
diff --git a/docs/API/API-COMPLETE-REFERENCE.md b/docs/API/API-COMPLETE-REFERENCE.md
index 6ef0bc17..9c466e20 100644
--- a/docs/API/API-COMPLETE-REFERENCE.md
+++ b/docs/API/API-COMPLETE-REFERENCE.md
@@ -95,12 +95,35 @@ Development: http://localhost:8000/api/v1/
 ```
 /api/v1/
 ├── auth/          # Authentication and user management
+├── account/       # Account settings, team, and usage analytics
+├── integration/   # Site integrations and sync
+├── system/        # Settings, prompts, integrations
+├── admin/billing/ # Admin-only billing management
+├── billing/       # Credits, transactions, usage
 ├── planner/       # Keywords, clusters, content ideas
 ├── writer/        # Tasks, content, images
-├── system/        # Settings, prompts, integrations
-└── billing/       # Credits, transactions, usage
+├── automation/    # Automation configuration and runs
+├── linker/        # Internal linking operations
+├── optimizer/     # Content optimization operations
+└── publisher/     # Publishing records and deployments
 ```
 
+### Module → Tag Map (Swagger/ReDoc)
+- Authentication → `Authentication`
+- Account → `Account`
+- Integration → `Integration`
+- System → `System`
+- Admin Billing → `Admin Billing`
+- Billing → `Billing`
+- Planner → `Planner`
+- Writer → `Writer`
+- Automation → `Automation`
+- Linker → `Linker`
+- Optimizer → `Optimizer`
+- Publisher → `Publisher`
+
+Tag display order (docs): Authentication, Account, Integration, System, Admin Billing, Billing, Planner, Writer, Automation, Linker, Optimizer, Publisher
+
 ### Technology Stack
 
 - **Framework**: Django REST Framework (DRF)
@@ -985,6 +1008,30 @@ class KeywordViewSet(SiteSectorModelViewSet):
 - `GET /api/v1/system/ping/` - Health check endpoint (AllowAny)
 - `GET /api/v1/system/request-metrics/{request_id}/` - Get request metrics for debugging
 
+### Admin Billing & Credits (Admin-only, Unified)
+
+**Base Path**: `/api/v1/admin/billing/` (all admin billing/credits live here)
+
+- `GET /api/v1/admin/billing/stats/` - System billing stats (admin-only)
+- `GET /api/v1/admin/billing/invoices/` - Admin invoice listing (all accounts)
+- `GET /api/v1/admin/billing/payments/` - Admin payment listing (all accounts)
+- `GET /api/v1/admin/billing/pending_payments/` - Pending manual payments (admin review queue)
+- `POST /api/v1/admin/billing/{id}/approve_payment/` - Approve manual payment (admin-only)
+- `POST /api/v1/admin/billing/{id}/reject_payment/` - Reject manual payment (admin-only)
+- `GET /api/v1/admin/credit-costs/` - List credit cost configurations (admin-only)
+- `POST /api/v1/admin/credit-costs/` - Update credit cost configurations (admin-only)
+- `GET /api/v1/admin/users/` - List users/accounts with credit info (admin-only)
+- `POST /api/v1/admin/users/{user_id}/adjust-credits/` - Adjust user credits (admin-only)
+
+> Non-standard/legacy endpoints to deprecate and remove (do not use):
+> - `/api/v1/billing/admin/stats/`
+> - `/api/v1/billing/admin/invoices/`
+> - `/api/v1/billing/admin/payments/`
+> - `/api/v1/billing/admin/pending_payments/`
+> - `/api/v1/billing/admin/{id}/approve_payment/`
+> - `/api/v1/billing/admin/{id}/reject_payment/`
+
+
 ### Billing Module Endpoints
 
 **Base Path**: `/api/v1/billing/`
@@ -994,7 +1041,7 @@ class KeywordViewSet(SiteSectorModelViewSet):
 **Base Path**: `/api/v1/billing/credits/balance/`  
 **Permission**: IsAuthenticatedAndActive + HasTenantAccess
 
-- `GET /api/v1/billing/credits/balance/balance/` - Get credit balance
+- `GET /api/v1/billing/credits/balance/` - Get credit balance
 
 **Response:**
 ```json
@@ -1041,6 +1088,52 @@ class KeywordViewSet(SiteSectorModelViewSet):
 - `start_date` - Filter by start date
 - `end_date` - Filter by end date
 
+#### Credit Packages
+
+**Base Path**: `/api/v1/billing/credit-packages/`  
+**Permission**: IsAuthenticated
+
+- `GET /api/v1/billing/credit-packages/` - List available credit packages
+- `POST /api/v1/billing/credit-packages/{id}/purchase/` - Purchase a credit package
+
+#### Invoices
+
+**Base Path**: `/api/v1/billing/invoices/`  
+**Permission**: IsAuthenticated
+
+- `GET /api/v1/billing/invoices/` - List invoices
+- `GET /api/v1/billing/invoices/{id}/` - Get invoice detail
+- `GET /api/v1/billing/invoices/{id}/download_pdf/` - Download invoice PDF
+
+#### Payment Methods
+
+**Base Path**: `/api/v1/billing/payment-methods/`  
+**Permission**: IsAuthenticated
+
+- `GET /api/v1/billing/payment-methods/` - List payment methods
+- `POST /api/v1/billing/payment-methods/` - Create payment method
+- `GET /api/v1/billing/payment-methods/{id}/` - Get payment method
+- `PUT /api/v1/billing/payment-methods/{id}/` - Update payment method
+- `PATCH /api/v1/billing/payment-methods/{id}/` - Partial update payment method
+- `DELETE /api/v1/billing/payment-methods/{id}/` - Delete payment method
+- `POST /api/v1/billing/payment-methods/{id}/set_default/` - Set default payment method
+- `GET /api/v1/billing/payment-methods/available/` - List available payment methods (config-driven)
+
+#### Payments
+
+**Base Path**: `/api/v1/billing/payments/`  
+**Permission**: IsAuthenticated
+
+- `GET /api/v1/billing/payments/` - List payments
+- `POST /api/v1/billing/payments/manual/` - Submit manual payment for approval
+
+#### Transactions (alias-free)
+
+**Base Path**: `/api/v1/billing/transactions/`  
+**Permission**: IsAuthenticated
+
+- `GET /api/v1/billing/transactions/` - List transactions (with current balance included)
+
 ---
 
 ## Integration Examples
@@ -1348,6 +1441,28 @@ All API changes are documented in `CHANGELOG.md` with:
 - Affected areas
 - Migration notes (if applicable)
 
+### Endpoint Change & Documentation Checklist (Unified API)
+
+1) Design
+- Map to an existing module/tag; if new, add to Module Namespaces and Tag Map.
+- Choose path under the correct base (`/api/v1/{module}/...`); avoid new sub-namespaces unless justified.
+
+2) Implement
+- Use unified response helpers and proper permissions/rate limits.
+- Add `extend_schema` tags matching the module tag.
+
+3) Schema & Docs
+- Ensure swagger tag exists in `SPECTACULAR_SETTINGS` with the agreed order.
+- Regenerate/reload the API (server restart) so `/api/schema/` reflects changes.
+- Verify in Swagger UI (`/api/docs/`) and ReDoc (`/api/redoc/`) that the operation is under the right tag.
+
+4) Reference Updates
+- Update this reference file with the new endpoint(s) under the correct module section.
+- Update `CHANGELOG.md` (type, summary, impacted clients).
+
+5) Deprecation (if applicable)
+- Mark legacy routes, add timeline, and keep compatibility shims only temporarily.
+
 ---
 
 ## Summary
diff --git a/frontend/src/pages/Settings/ApiMonitor.tsx b/frontend/src/pages/Settings/ApiMonitor.tsx
index b05c22ef..976f73ab 100644
--- a/frontend/src/pages/Settings/ApiMonitor.tsx
+++ b/frontend/src/pages/Settings/ApiMonitor.tsx
@@ -109,6 +109,7 @@ const endpointGroups: EndpointGroup[] = [
       { path: "/v1/system/settings/account/", method: "GET", description: "Account settings" },
       { path: "/v1/billing/credits/balance/", method: "GET", description: "Credit balance" },
       { path: "/v1/billing/credits/usage/", method: "GET", description: "Usage logs" },
+      { path: "/v1/billing/credits/transactions/", method: "GET", description: "Transactions" },
       { path: "/v1/billing/credits/usage/summary/", method: "GET", description: "Usage summary" },
       { 
         path: "/v1/billing/credits/usage/limits/", 
@@ -126,6 +127,36 @@ const endpointGroups: EndpointGroup[] = [
       { path: "/v1/billing/credits/transactions/", method: "GET", description: "Transactions" },
     ],
   },
+  {
+    name: "Billing (Customer)",
+    endpoints: [
+      { path: "/v1/billing/credit-packages/", method: "GET", description: "List credit packages" },
+      { path: "/v1/billing/invoices/", method: "GET", description: "List invoices" },
+      { path: "/v1/billing/payments/", method: "GET", description: "List payments" },
+      { path: "/v1/billing/payment-methods/", method: "GET", description: "List payment methods" },
+      { path: "/v1/billing/payment-methods/available/", method: "GET", description: "Available payment methods" },
+      { path: "/v1/billing/payments/manual/", method: "POST", description: "Submit manual payment" },
+      { path: "/v1/billing/payments/available_methods/", method: "GET", description: "Payment methods (available_methods)" },
+      { path: "/v1/billing/payment-methods/1/set_default/", method: "POST", description: "Set default payment method (sample id)" },
+      { path: "/v1/billing/payment-methods/1/", method: "PATCH", description: "Update payment method (sample id)" },
+      { path: "/v1/billing/payment-methods/1/", method: "DELETE", description: "Delete payment method (sample id)" },
+    ],
+  },
+  {
+    name: "Admin Billing",
+    endpoints: [
+      { path: "/v1/admin/billing/stats/", method: "GET", description: "Admin billing stats" },
+      { path: "/v1/admin/billing/invoices/", method: "GET", description: "Admin invoices" },
+      { path: "/v1/admin/billing/payments/", method: "GET", description: "Admin payments" },
+      { path: "/v1/admin/billing/pending_payments/", method: "GET", description: "Pending manual payments" },
+      { path: "/v1/admin/billing/1/approve_payment/", method: "POST", description: "Approve manual payment (sample id)" },
+      { path: "/v1/admin/billing/1/reject_payment/", method: "POST", description: "Reject manual payment (sample id)" },
+      { path: "/v1/admin/credit-costs/", method: "GET", description: "Credit cost configs" },
+      { path: "/v1/admin/credit-costs/", method: "POST", description: "Update credit cost configs" },
+      { path: "/v1/admin/users/", method: "GET", description: "Admin users with credits" },
+      { path: "/v1/admin/users/1/adjust-credits/", method: "POST", description: "Adjust credits (sample id)" },
+    ],
+  },
   {
     name: "CRUD Operations - Planner",
     endpoints: [
diff --git a/frontend/src/services/billing.api.ts b/frontend/src/services/billing.api.ts
index b0e021bd..922d4226 100644
--- a/frontend/src/services/billing.api.ts
+++ b/frontend/src/services/billing.api.ts
@@ -193,7 +193,7 @@ export interface PendingPayment extends Payment {
 
 export async function getCreditBalance(): Promise<CreditBalance> {
   // Use business billing CreditTransactionViewSet.balance
-  return fetchAPI('/v1/billing/transactions/balance/');
+  return fetchAPI('/v1/billing/credits/balance/');
 }
 
 export async function getCreditTransactions(): Promise<{
@@ -268,7 +268,7 @@ export async function getCreditUsageLimits(): Promise<{
 export async function getAdminBillingStats(): Promise<AdminBillingStats> {
   // Admin billing dashboard metrics
   // Use business billing stats endpoint to include revenue, accounts, credits, and recent payments
-  return fetchAPI('/v1/billing/admin/stats/');
+  return fetchAPI('/v1/admin/billing/stats/');
 }
 
 export async function getAdminInvoices(params?: { status?: string; account_id?: number; search?: string }): Promise<{
@@ -280,7 +280,7 @@ export async function getAdminInvoices(params?: { status?: string; account_id?:
   if (params?.account_id) queryParams.append('account_id', String(params.account_id));
   if (params?.search) queryParams.append('search', params.search);
 
-  const url = `/v1/billing/admin/invoices/${queryParams.toString() ? '?' + queryParams.toString() : ''}`;
+  const url = `/v1/admin/billing/invoices/${queryParams.toString() ? '?' + queryParams.toString() : ''}`;
   return fetchAPI(url);
 }
 
@@ -293,7 +293,7 @@ export async function getAdminPayments(params?: { status?: string; account_id?:
   if (params?.account_id) queryParams.append('account_id', String(params.account_id));
   if (params?.payment_method) queryParams.append('payment_method', params.payment_method);
 
-  const url = `/v1/billing/admin/payments/${queryParams.toString() ? '?' + queryParams.toString() : ''}`;
+  const url = `/v1/admin/billing/payments/${queryParams.toString() ? '?' + queryParams.toString() : ''}`;
   return fetchAPI(url);
 }
 
@@ -624,7 +624,7 @@ export async function getPendingPayments(): Promise<{
   results: PendingPayment[];
   count: number;
 }> {
-  return fetchAPI('/v1/billing/admin/pending_payments/');
+  return fetchAPI('/v1/admin/billing/pending_payments/');
 }
 
 export async function approvePayment(paymentId: number, data?: {
@@ -633,7 +633,7 @@ export async function approvePayment(paymentId: number, data?: {
   message: string;
   payment: Payment;
 }> {
-  return fetchAPI(`/v1/billing/admin/${paymentId}/approve_payment/`, {
+  return fetchAPI(`/v1/admin/billing/${paymentId}/approve_payment/`, {
     method: 'POST',
     body: JSON.stringify(data || {}),
   });
@@ -646,7 +646,7 @@ export async function rejectPayment(paymentId: number, data: {
   message: string;
   payment: Payment;
 }> {
-  return fetchAPI(`/v1/billing/admin/${paymentId}/reject_payment/`, {
+  return fetchAPI(`/v1/admin/billing/${paymentId}/reject_payment/`, {
     method: 'POST',
     body: JSON.stringify(data),
   });