diff --git a/docs/entitlements.md b/docs/entitlements.md
new file mode 100644
index 000000000..5b47c5df6
--- /dev/null
+++ b/docs/entitlements.md
@@ -0,0 +1,140 @@
+# Entitlements System
+
+The entitlements system provides a pluggable backend architecture for checking user access rights and synchronizing mail domain admin permissions. It integrates with the DeployCenter (Espace Operateur) API in production and uses a local backend for development.
+
+## Architecture
+
+```text
+┌─────────────────────────────────────────────┐
+│   OIDC Authentication Backend               │
+│   _sync_entitlements() on every login       │
+└──────────────┬──────────────────────────────┘
+               │
+┌──────────────▼──────────────────────────────┐
+│   Service Layer                             │
+│   get_user_entitlements()                   │
+└──────────────┬──────────────────────────────┘
+               │
+┌──────────────▼──────────────────────────────┐
+│   Backend Factory (singleton)               │
+│   get_entitlements_backend()                │
+└──────────────┬──────────────────────────────┘
+               │
+       ┌───────┴───────┐
+       │               │
+┌──────▼─────┐  ┌──────▼───────────────┐
+│   Local    │  │   DeployCenter       │
+│  Backend   │  │   Backend            │
+│ (dev/test) │  │ (production, cached) │
+└────────────┘  └──────────────────────┘
+```
+
+### Components
+
+- **Service layer** (`core/entitlements/__init__.py`): Public `get_user_entitlements()` function and `EntitlementsUnavailableError` exception.
+- **Backend factory** (`core/entitlements/factory.py`): `@functools.cache` singleton that imports and instantiates the configured backend class.
+- **Abstract base** (`core/entitlements/backends/base.py`): Defines the `EntitlementsBackend` interface.
+- **Local backend** (`core/entitlements/backends/local.py`): Always grants access, returns `None` for `can_admin_maildomains` (disabling sync).
+- **DeployCenter backend** (`core/entitlements/backends/deploycenter.py`): Calls the DeployCenter API with internal Django cache.
+- **OIDC sync** (`core/authentication/backends.py`): Syncs `MailDomainAccess` ADMIN records on every login based on `can_admin_maildomains`.
+
+### Error Handling
+
+- **Login sync is fail-open**: if the entitlements service is unavailable during OIDC login, existing `MailDomainAccess` records are preserved and the user is allowed in.
+- The DeployCenter backend falls back to stale cached data when the API is unavailable.
+- `EntitlementsUnavailableError` is only raised when the API fails and no cache exists.
+
+## Configuration
+
+### Environment Variables
+
+| Variable | Default | Description |
+|---|---|---|
+| `ENTITLEMENTS_BACKEND` | `core.entitlements.backends.local.LocalEntitlementsBackend` | Python import path of the backend class |
+| `ENTITLEMENTS_BACKEND_PARAMETERS` | `{}` | JSON object of parameters passed to the backend constructor |
+| `ENTITLEMENTS_CACHE_TIMEOUT` | `300` | Cache TTL in seconds |
+
+### DeployCenter Backend Parameters
+
+When using `core.entitlements.backends.deploycenter.DeployCenterEntitlementsBackend`, provide these in `ENTITLEMENTS_BACKEND_PARAMETERS`:
+
+```json
+{
+  "base_url": "https://deploycenter.example.com/api/v1.0/entitlements/",
+  "service_id": "42",
+  "api_key": "your-api-key",
+  "timeout": 10,
+  "oidc_claims": ["siret"]
+}
+```
+
+| Parameter | Required | Description |
+|---|---|---|
+| `base_url` | Yes | Full URL of the DeployCenter entitlements endpoint |
+| `service_id` | Yes | Service identifier in DeployCenter |
+| `api_key` | Yes | API key for `X-Service-Auth` header |
+| `timeout` | No | HTTP timeout in seconds (default: 10) |
+| `oidc_claims` | No | List of OIDC claim names to extract from user_info and forward as query params (e.g. `["siret"]`) |
+
+### Example Production Configuration
+
+```bash
+ENTITLEMENTS_BACKEND=core.entitlements.backends.deploycenter.DeployCenterEntitlementsBackend
+ENTITLEMENTS_BACKEND_PARAMETERS='{"base_url":"https://deploycenter.example.com/api/v1.0/entitlements/","service_id":"42","api_key":"secret-key","timeout":10,"oidc_claims":["siret"]}'
+ENTITLEMENTS_CACHE_TIMEOUT=300
+```
+
+## Backend Interface
+
+Custom backends must extend `EntitlementsBackend` and implement:
+
+```python
+class MyBackend(EntitlementsBackend):
+    def __init__(self, **kwargs):
+        # Receive ENTITLEMENTS_BACKEND_PARAMETERS as kwargs
+        pass
+
+    def get_user_entitlements(self, user_sub, user_email, user_info=None, force_refresh=False):
+        # Return: {"can_access": bool, "can_admin_maildomains": list[str] | None}
+        # Return None for can_admin_maildomains to skip domain admin sync.
+        # Raise EntitlementsUnavailableError on failure.
+        pass
+```
+
+## DeployCenter API
+
+The DeployCenter backend calls:
+
+```text
+GET {base_url}?service_id=X&account_type=user&account_email=X&siret=X
+```
+
+Headers:
+- `X-Service-Auth: Bearer {api_key}`
+
+Query parameters include any configured `oidc_claims` extracted from the OIDC user_info response (e.g. `siret`).
+
+Response: `{"entitlements": {"can_access": bool, "can_admin_maildomains": [str], ...}}`
+
+## OIDC Login Integration
+
+During OIDC login (`post_get_or_create_user`), the system:
+
+1. Calls `get_user_entitlements` with `force_refresh=True` (resets cache)
+2. Syncs `MailDomainAccess` ADMIN records based on `can_admin_maildomains`:
+   - Compares entitled domains with existing records (optimistic early return if in sync)
+   - Creates missing admin accesses for entitled domains (using `update_or_create`)
+   - Removes admin accesses for domains not in the entitled list
+3. If `can_admin_maildomains` is `None` (e.g. local backend), sync is skipped entirely
+4. If the entitlements service is unavailable, existing accesses are preserved (fail-open)
+
+### Caching Behavior
+
+- The DeployCenter backend caches entitlements in Django's cache framework (TTL: `ENTITLEMENTS_CACHE_TIMEOUT`).
+- On login, `force_refresh=True` bypasses the cache to fetch fresh data.
+- If the API fails during a forced refresh, stale cached data is returned as fallback.
+- Logging out and back in triggers a fresh fetch, effectively resetting the cache for that user.
+
+### Deployment Consideration
+
+Before enabling the DeployCenter backend in production, ensure that existing domain admin assignments are present in DeployCenter. The entitlements sync will **remove** admin accesses that are not in the DeployCenter response.
diff --git a/src/backend/core/api/openapi.json b/src/backend/core/api/openapi.json
index 06338c4ee..97bcc8e84 100644
--- a/src/backend/core/api/openapi.json
+++ b/src/backend/core/api/openapi.json
@@ -245,6 +245,14 @@
                                             "description": "Whether external images should be proxied",
                                             "readOnly": true
                                         },
+                                        "FEATURE_MAILDOMAIN_CREATE": {
+                                            "type": "boolean",
+                                            "readOnly": true
+                                        },
+                                        "FEATURE_MAILDOMAIN_MANAGE_ACCESSES": {
+                                            "type": "boolean",
+                                            "readOnly": true
+                                        },
                                         "MESSAGES_MANUAL_RETRY_MAX_AGE": {
                                             "type": "integer",
                                             "description": "Maximum age in seconds for a message to be eligible for manual retry of failed deliveries",
@@ -267,6 +275,8 @@
                                         "MAX_RECIPIENTS_PER_MESSAGE",
                                         "MAX_TEMPLATE_IMAGE_SIZE",
                                         "IMAGE_PROXY_ENABLED",
+                                        "FEATURE_MAILDOMAIN_CREATE",
+                                        "FEATURE_MAILDOMAIN_MANAGE_ACCESSES",
                                         "MESSAGES_MANUAL_RETRY_MAX_AGE"
                                     ]
                                 }
diff --git a/src/backend/core/api/permissions.py b/src/backend/core/api/permissions.py
index 5bb2b5410..b017a5508 100644
--- a/src/backend/core/api/permissions.py
+++ b/src/backend/core/api/permissions.py
@@ -15,6 +15,13 @@
 }
 
 
+class DenyAll(permissions.BasePermission):
+    """Always denies access. Used to disable endpoints via feature flags."""
+
+    def has_permission(self, request, view):
+        return False
+
+
 class IsAuthenticated(permissions.BasePermission):
     """
     Allows access only to authenticated users. Alternative method checking the presence
@@ -423,6 +430,18 @@ def has_permission(self, request, view):
         )
 
 
+class HasProvisioningApiKey(permissions.BasePermission):
+    """Allows access only to requests bearing the provisioning API key."""
+
+    def has_permission(self, request, view):
+        if not settings.PROVISIONING_API_KEY:
+            return False
+        return compare_digest(
+            request.headers.get("Authorization") or "",
+            f"Bearer {settings.PROVISIONING_API_KEY}",
+        )
+
+
 class HasAccessToMailbox(IsAuthenticated):
     """Allows access only to users with the access to the mailbox."""
 
diff --git a/src/backend/core/api/serializers.py b/src/backend/core/api/serializers.py
index 9647f73db..7cfeb9103 100644
--- a/src/backend/core/api/serializers.py
+++ b/src/backend/core/api/serializers.py
@@ -1759,3 +1759,34 @@ def create(self, validated_data):
 
     def update(self, instance, validated_data):
         """This serializer is only used to validate the data, not to create or update."""
+
+
+class DomainsField(serializers.Field):
+    """Accepts either a JSON list of strings or a comma-separated string."""
+
+    def to_internal_value(self, data):
+        if isinstance(data, str):
+            data = [d.strip() for d in data.split(",") if d.strip()]
+        if not isinstance(data, list):
+            raise serializers.ValidationError(
+                "Expected a list of domains or a comma-separated string."
+            )
+        if not data:
+            raise serializers.ValidationError("At least one domain is required.")
+        return data
+
+    def to_representation(self, value):
+        return value
+
+
+class ProvisioningMailDomainSerializer(serializers.Serializer):
+    """Serializer for the provisioning endpoint that creates mail domains."""
+
+    domains = DomainsField()
+    custom_attributes = serializers.JSONField(required=False, default=dict)
+
+    def create(self, validated_data):
+        """This serializer is only used to validate the data, not to create or update."""
+
+    def update(self, instance, validated_data):
+        """This serializer is only used to validate the data, not to create or update."""
diff --git a/src/backend/core/api/viewsets/config.py b/src/backend/core/api/viewsets/config.py
index 3493931ea..d3787a8f4 100644
--- a/src/backend/core/api/viewsets/config.py
+++ b/src/backend/core/api/viewsets/config.py
@@ -111,6 +111,14 @@ class ConfigView(drf.views.APIView):
                             "description": "Whether external images should be proxied",
                             "readOnly": True,
                         },
+                        "FEATURE_MAILDOMAIN_CREATE": {
+                            "type": "boolean",
+                            "readOnly": True,
+                        },
+                        "FEATURE_MAILDOMAIN_MANAGE_ACCESSES": {
+                            "type": "boolean",
+                            "readOnly": True,
+                        },
                         "MESSAGES_MANUAL_RETRY_MAX_AGE": {
                             "type": "integer",
                             "description": (
@@ -136,6 +144,8 @@ class ConfigView(drf.views.APIView):
                         "MAX_RECIPIENTS_PER_MESSAGE",
                         "MAX_TEMPLATE_IMAGE_SIZE",
                         "IMAGE_PROXY_ENABLED",
+                        "FEATURE_MAILDOMAIN_CREATE",
+                        "FEATURE_MAILDOMAIN_MANAGE_ACCESSES",
                         "MESSAGES_MANUAL_RETRY_MAX_AGE",
                     ],
                 },
@@ -158,6 +168,8 @@ def get(self, request):
             "IMAGE_PROXY_ENABLED",
             "MESSAGES_MANUAL_RETRY_MAX_AGE",
             "FEATURE_MAILBOX_ADMIN_CHANNELS",
+            "FEATURE_MAILDOMAIN_CREATE",
+            "FEATURE_MAILDOMAIN_MANAGE_ACCESSES",
             "MAX_OUTGOING_ATTACHMENT_SIZE",
             "MAX_OUTGOING_BODY_SIZE",
             "MAX_INCOMING_EMAIL_SIZE",
diff --git a/src/backend/core/api/viewsets/maildomain.py b/src/backend/core/api/viewsets/maildomain.py
index f4682aa01..5bcc730fc 100644
--- a/src/backend/core/api/viewsets/maildomain.py
+++ b/src/backend/core/api/viewsets/maildomain.py
@@ -56,6 +56,8 @@ class AdminMailDomainViewSet(
 
     def get_permissions(self):
         if self.action == "create":
+            if not settings.FEATURE_MAILDOMAIN_CREATE:
+                return [core_permissions.DenyAll()]
             return [core_permissions.IsSuperUser()]
         return super().get_permissions()
 
diff --git a/src/backend/core/api/viewsets/maildomain_access.py b/src/backend/core/api/viewsets/maildomain_access.py
index 2b5ffb228..2db286a2f 100644
--- a/src/backend/core/api/viewsets/maildomain_access.py
+++ b/src/backend/core/api/viewsets/maildomain_access.py
@@ -1,5 +1,6 @@
 """API ViewSet for MaildomainAccess model."""
 
+from django.conf import settings
 from django.shortcuts import get_object_or_404
 
 from drf_spectacular.utils import extend_schema
@@ -31,6 +32,12 @@ class MaildomainAccessViewSet(
     lookup_field = "pk"
     pagination_class = None
 
+    def get_permissions(self):
+        if self.action in ("create", "destroy"):
+            if not settings.FEATURE_MAILDOMAIN_MANAGE_ACCESSES:
+                return [core_permissions.DenyAll()]
+        return super().get_permissions()
+
     def get_serializer_class(self):
         """Select serializer based on action."""
         if self.action in ["create", "update", "partial_update"]:
diff --git a/src/backend/core/api/viewsets/provisioning.py b/src/backend/core/api/viewsets/provisioning.py
new file mode 100644
index 000000000..b1924e212
--- /dev/null
+++ b/src/backend/core/api/viewsets/provisioning.py
@@ -0,0 +1,74 @@
+"""API view for provisioning mail domains from DeployCenter."""
+
+import logging
+
+from django.core.exceptions import ValidationError
+from django.db import IntegrityError
+
+from drf_spectacular.utils import extend_schema
+from rest_framework import status
+from rest_framework.response import Response
+from rest_framework.views import APIView
+from sentry_sdk import capture_exception
+
+from core.api.permissions import HasProvisioningApiKey
+from core.api.serializers import ProvisioningMailDomainSerializer
+from core.models import MailDomain
+
+logger = logging.getLogger(__name__)
+
+
+class ProvisioningMailDomainView(APIView):
+    """Provision mail domains from DeployCenter webhooks."""
+
+    permission_classes = [HasProvisioningApiKey]
+    authentication_classes = []
+
+    @extend_schema(exclude=True)
+    def post(self, request):
+        """Provision mail domains from a list of domain names."""
+        serializer = ProvisioningMailDomainSerializer(data=request.data)
+        serializer.is_valid(raise_exception=True)
+
+        domains = serializer.validated_data["domains"]
+        custom_attributes = serializer.validated_data.get("custom_attributes", {})
+
+        created = []
+        existing = []
+        errors = []
+
+        for domain_name in domains:
+            try:
+                domain, was_created = MailDomain.objects.get_or_create(
+                    name=domain_name,
+                    defaults={"custom_attributes": custom_attributes},
+                )
+                if was_created:
+                    created.append(domain_name)
+                else:
+                    if domain.custom_attributes != custom_attributes:
+                        domain.custom_attributes = custom_attributes
+                        domain.save()
+                    existing.append(domain_name)
+            except ValidationError as e:
+                errors.append({"domain": domain_name, "error": str(e)})
+            except IntegrityError as exc:
+                capture_exception(exc)
+                logger.exception(
+                    "IntegrityError while provisioning domain %s", domain_name
+                )
+                errors.append(
+                    {
+                        "domain": domain_name,
+                        "error": "Failed to provision domain.",
+                    }
+                )
+
+        return Response(
+            {
+                "created": created,
+                "existing": existing,
+                "errors": errors,
+            },
+            status=status.HTTP_200_OK,
+        )
diff --git a/src/backend/core/authentication/backends.py b/src/backend/core/authentication/backends.py
index 795f8874b..d1e948f6b 100644
--- a/src/backend/core/authentication/backends.py
+++ b/src/backend/core/authentication/backends.py
@@ -10,13 +10,15 @@
     OIDCAuthenticationBackend as LaSuiteOIDCAuthenticationBackend,
 )
 
-from core.enums import MailboxRoleChoices
+from core.entitlements import EntitlementsUnavailableError, get_user_entitlements
+from core.enums import MailboxRoleChoices, MailDomainAccessRoleChoices
 from core.models import (
     Contact,
     DuplicateEmailError,
     Mailbox,
     MailboxAccess,
     MailDomain,
+    MailDomainAccess,
     User,
 )
 
@@ -48,6 +50,7 @@ def get_or_create_user(self, access_token, id_token, payload):
         """
         _user_created = False
         user_info = self.get_userinfo(access_token, id_token, payload)
+        self._user_info = user_info  # pylint: disable=attribute-defined-outside-init
 
         if not self.verify_claims(user_info):
             msg = "Claims verification failed"
@@ -87,6 +90,69 @@ def post_get_or_create_user(self, user, claims, _user_created):
         """Post-get or create user."""
         if user:
             self.autojoin_mailbox(user)
+            self._sync_entitlements(user)
+
+    def _sync_entitlements(self, user):
+        """Fetch user entitlements and sync MailDomainAccess ADMIN records.
+
+        Called on every login. Uses force_refresh=True to reset the cache.
+        If the entitlements backend is unavailable, existing accesses are preserved.
+        """
+        user_info = getattr(self, "_user_info", None)
+
+        try:
+            entitlements = get_user_entitlements(
+                user.sub, user.email, user_info=user_info, force_refresh=True
+            )
+        except EntitlementsUnavailableError:
+            logger.warning("Entitlements service unavailable during login")
+            return
+
+        admin_domains = entitlements.get("can_admin_maildomains")
+        if admin_domains is None:
+            # Backend doesn't support this field (e.g. dummy), skip sync
+            return
+
+        if not isinstance(admin_domains, (list, tuple, set)):
+            logger.warning(
+                "Invalid type for can_admin_maildomains: %s, skipping sync",
+                type(admin_domains).__name__,
+            )
+            return
+
+        # Resolve domain names to MailDomain objects that exist in DB
+        entitled_domains = list(MailDomain.objects.filter(name__in=admin_domains))
+        entitled_domain_ids = {d.id for d in entitled_domains}
+
+        # Get current ADMIN accesses for this user
+        existing_accesses = MailDomainAccess.objects.filter(
+            user=user, role=MailDomainAccessRoleChoices.ADMIN
+        )
+        existing_domain_ids = set(
+            existing_accesses.values_list("maildomain_id", flat=True)
+        )
+
+        # Optimistic path: if already in sync, skip all writes
+        if entitled_domain_ids == existing_domain_ids:
+            return
+
+        # Add new accesses
+        for domain in entitled_domains:
+            if domain.id not in existing_domain_ids:
+                MailDomainAccess.objects.update_or_create(
+                    user=user,
+                    maildomain=domain,
+                    defaults={"role": MailDomainAccessRoleChoices.ADMIN},
+                )
+
+        # Remove stale accesses (domains not in the entitled list)
+        stale_domain_ids = existing_domain_ids - entitled_domain_ids
+        if stale_domain_ids:
+            MailDomainAccess.objects.filter(
+                user=user,
+                maildomain_id__in=stale_domain_ids,
+                role=MailDomainAccessRoleChoices.ADMIN,
+            ).delete()
 
     def get_extra_claims(self, user_info):
         """Get extra claims."""
diff --git a/src/backend/core/entitlements/__init__.py b/src/backend/core/entitlements/__init__.py
new file mode 100644
index 000000000..1bc8841ba
--- /dev/null
+++ b/src/backend/core/entitlements/__init__.py
@@ -0,0 +1,28 @@
+"""Entitlements service layer."""
+
+from core.entitlements.factory import get_entitlements_backend
+
+
+class EntitlementsUnavailableError(Exception):
+    """Raised when the entitlements backend cannot be reached or returns an error."""
+
+
+def get_user_entitlements(user_sub, user_email, user_info=None, force_refresh=False):
+    """Get user entitlements, delegating to the configured backend.
+
+    Args:
+        user_sub: The user's OIDC subject identifier.
+        user_email: The user's email address.
+        user_info: The full OIDC user_info dict (forwarded to backend).
+        force_refresh: If True, bypass backend cache and fetch fresh data.
+
+    Returns:
+        dict: {"can_access": bool, "can_admin_maildomains": list[str] | None}
+
+    Raises:
+        EntitlementsUnavailableError: If the backend cannot be reached and no cache exists.
+    """
+    backend = get_entitlements_backend()
+    return backend.get_user_entitlements(
+        user_sub, user_email, user_info=user_info, force_refresh=force_refresh
+    )
diff --git a/src/backend/core/entitlements/backends/__init__.py b/src/backend/core/entitlements/backends/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/src/backend/core/entitlements/backends/base.py b/src/backend/core/entitlements/backends/base.py
new file mode 100644
index 000000000..be85ae4ad
--- /dev/null
+++ b/src/backend/core/entitlements/backends/base.py
@@ -0,0 +1,29 @@
+"""Abstract base class for entitlements backends."""
+
+from abc import ABC, abstractmethod
+
+
+class EntitlementsBackend(ABC):
+    """Abstract base class that defines the interface for entitlements backends."""
+
+    @abstractmethod
+    def get_user_entitlements(
+        self, user_sub, user_email, user_info=None, force_refresh=False
+    ):
+        """Fetch user entitlements.
+
+        Args:
+            user_sub: The user's OIDC subject identifier.
+            user_email: The user's email address.
+            user_info: The full OIDC user_info dict (backends may extract claims from it).
+            force_refresh: If True, bypass any cache and fetch fresh data.
+
+        Returns:
+            dict: {
+                "can_access": bool,
+                "can_admin_maildomains": list[str] | None,
+            }
+
+        Raises:
+            EntitlementsUnavailableError: If the backend cannot be reached.
+        """
diff --git a/src/backend/core/entitlements/backends/deploycenter.py b/src/backend/core/entitlements/backends/deploycenter.py
new file mode 100644
index 000000000..8dd56303f
--- /dev/null
+++ b/src/backend/core/entitlements/backends/deploycenter.py
@@ -0,0 +1,113 @@
+"""DeployCenter (Espace Operateur) entitlements backend."""
+
+import logging
+
+from django.conf import settings
+from django.core.cache import cache
+
+import requests
+
+from core.entitlements import EntitlementsUnavailableError
+from core.entitlements.backends.base import EntitlementsBackend
+
+logger = logging.getLogger(__name__)
+
+
+class DeployCenterEntitlementsBackend(EntitlementsBackend):
+    """Backend that fetches entitlements from the DeployCenter API.
+
+    Args:
+        base_url: Full URL of the entitlements endpoint
+            (e.g. "https://dc.example.com/api/v1.0/entitlements/").
+        service_id: The service identifier in DeployCenter.
+        api_key: API key for X-Service-Auth header.
+        timeout: HTTP request timeout in seconds.
+        oidc_claims: List of OIDC claim names to extract from user_info
+            and forward as query params (e.g. ["siret"]).
+    """
+
+    def __init__(
+        self, base_url, service_id, api_key, timeout=10, oidc_claims=None, **kwargs
+    ):
+        super().__init__(**kwargs)
+        self.base_url = base_url
+        self.service_id = service_id
+        self.api_key = api_key
+        self.timeout = timeout
+        self.oidc_claims = oidc_claims or []
+
+    def _cache_key(self, user_sub):
+        return f"entitlements:user:{user_sub}"
+
+    def _make_request(self, user_email, user_info=None):
+        """Make a request to the DeployCenter entitlements API.
+
+        Returns:
+            dict | None: The response data, or None on failure.
+        """
+        params = {
+            "service_id": self.service_id,
+            "account_type": "user",
+            "account_email": user_email,
+        }
+
+        # Forward configured OIDC claims as query params
+        if user_info:
+            for claim in self.oidc_claims:
+                if claim in user_info:
+                    params[claim] = user_info[claim]
+
+        headers = {
+            "X-Service-Auth": f"Bearer {self.api_key}",
+        }
+
+        try:
+            response = requests.get(
+                self.base_url, params=params, headers=headers, timeout=self.timeout
+            )
+            response.raise_for_status()
+            return response.json()
+        except (requests.RequestException, ValueError):
+            email_domain = user_email.split("@")[-1] if "@" in user_email else "?"
+            logger.warning(
+                "DeployCenter entitlements request failed for user@%s",
+                email_domain,
+                exc_info=True,
+            )
+            return None
+
+    def get_user_entitlements(
+        self, user_sub, user_email, user_info=None, force_refresh=False
+    ):
+        """Fetch user entitlements from DeployCenter with caching.
+
+        On cache miss or force_refresh: fetches from the API.
+        On API failure: falls back to stale cache if available,
+        otherwise raises EntitlementsUnavailableError.
+        """
+        cache_key = self._cache_key(user_sub)
+
+        if not force_refresh:
+            cached = cache.get(cache_key)
+            if cached is not None:
+                return cached
+
+        data = self._make_request(user_email, user_info=user_info)
+
+        if data is None:
+            # API failed — try stale cache as fallback
+            cached = cache.get(cache_key)
+            if cached is not None:
+                return cached
+            raise EntitlementsUnavailableError(
+                "Failed to fetch user entitlements from DeployCenter"
+            )
+
+        entitlements = data.get("entitlements", {})
+        result = {
+            "can_access": entitlements.get("can_access", False),
+            "can_admin_maildomains": entitlements.get("can_admin_maildomains"),
+        }
+
+        cache.set(cache_key, result, settings.ENTITLEMENTS_CACHE_TIMEOUT)
+        return result
diff --git a/src/backend/core/entitlements/backends/local.py b/src/backend/core/entitlements/backends/local.py
new file mode 100644
index 000000000..3485be45a
--- /dev/null
+++ b/src/backend/core/entitlements/backends/local.py
@@ -0,0 +1,16 @@
+"""Local entitlements backend for development and testing."""
+
+from core.entitlements.backends.base import EntitlementsBackend
+
+
+class LocalEntitlementsBackend(EntitlementsBackend):
+    """Local backend that always grants access. Returns None for
+    can_admin_maildomains to signal that domain admin sync is not supported."""
+
+    def get_user_entitlements(
+        self, user_sub, user_email, user_info=None, force_refresh=False
+    ):
+        return {
+            "can_access": True,
+            "can_admin_maildomains": None,
+        }
diff --git a/src/backend/core/entitlements/factory.py b/src/backend/core/entitlements/factory.py
new file mode 100644
index 000000000..c5564f7c7
--- /dev/null
+++ b/src/backend/core/entitlements/factory.py
@@ -0,0 +1,13 @@
+"""Factory for creating entitlements backend instances."""
+
+import functools
+
+from django.conf import settings
+from django.utils.module_loading import import_string
+
+
+@functools.cache
+def get_entitlements_backend():
+    """Return a singleton instance of the configured entitlements backend."""
+    backend_class = import_string(settings.ENTITLEMENTS_BACKEND)
+    return backend_class(**settings.ENTITLEMENTS_BACKEND_PARAMETERS)
diff --git a/src/backend/core/tests/api/test_admin_maildomains_create.py b/src/backend/core/tests/api/test_admin_maildomains_create.py
index 9561e5fa8..1ae231f65 100644
--- a/src/backend/core/tests/api/test_admin_maildomains_create.py
+++ b/src/backend/core/tests/api/test_admin_maildomains_create.py
@@ -1,6 +1,7 @@
 """Tests for the MailDomain Admin API endpoints."""
 # pylint: disable=redefined-outer-name, unused-argument
 
+from django.test import override_settings
 from django.urls import reverse
 
 import pytest
@@ -92,3 +93,14 @@ def test_create_mail_domain_duplicate_name(self, api_client, domain_superuser_us
             self.CREATE_DOMAIN_URL, {"name": "dup.com"}, format="json"
         )
         assert response.status_code == status.HTTP_400_BAD_REQUEST
+
+    @override_settings(FEATURE_MAILDOMAIN_CREATE=False)
+    def test_create_mail_domain_feature_flag_disabled(
+        self, api_client, domain_superuser_user
+    ):
+        """Superuser should get 403 when FEATURE_MAILDOMAIN_CREATE is False."""
+        api_client.force_authenticate(user=domain_superuser_user)
+        data = {"name": "blocked-domain.com"}
+        response = api_client.post(self.CREATE_DOMAIN_URL, data, format="json")
+        assert response.status_code == status.HTTP_403_FORBIDDEN
+        assert not models.MailDomain.objects.filter(name="blocked-domain.com").exists()
diff --git a/src/backend/core/tests/api/test_config.py b/src/backend/core/tests/api/test_config.py
index e73d97d34..313c4215d 100644
--- a/src/backend/core/tests/api/test_config.py
+++ b/src/backend/core/tests/api/test_config.py
@@ -24,6 +24,8 @@
     FEATURE_AI_SUMMARY=False,
     FEATURE_AI_AUTOLABELS=False,
     FEATURE_MAILBOX_ADMIN_CHANNELS=[],
+    FEATURE_MAILDOMAIN_CREATE=True,
+    FEATURE_MAILDOMAIN_MANAGE_ACCESSES=True,
     DRIVE_CONFIG={"base_url": None, "app_name": "Drive"},
     MAX_OUTGOING_ATTACHMENT_SIZE=20971520,  # 20MB
     MAX_OUTGOING_BODY_SIZE=5242880,  # 5MB
@@ -52,6 +54,8 @@ def test_api_config(is_authenticated):
         "FEATURE_AI_SUMMARY": False,
         "FEATURE_AI_AUTOLABELS": False,
         "FEATURE_MAILBOX_ADMIN_CHANNELS": [],
+        "FEATURE_MAILDOMAIN_CREATE": True,
+        "FEATURE_MAILDOMAIN_MANAGE_ACCESSES": True,
         "SCHEMA_CUSTOM_ATTRIBUTES_USER": {},
         "SCHEMA_CUSTOM_ATTRIBUTES_MAILDOMAIN": {},
         "MAX_INCOMING_EMAIL_SIZE": 10485760,
diff --git a/src/backend/core/tests/api/test_maildomain_access.py b/src/backend/core/tests/api/test_maildomain_access.py
index 24d8adb2c..f32964713 100644
--- a/src/backend/core/tests/api/test_maildomain_access.py
+++ b/src/backend/core/tests/api/test_maildomain_access.py
@@ -2,6 +2,7 @@
 # pylint: disable=unused-argument
 
 from django.contrib.auth.models import AnonymousUser
+from django.test import override_settings
 from django.urls import reverse
 
 import pytest
@@ -409,3 +410,50 @@ def test_admin_api_maildomain_accesses_excludes_abilities_with_superuser(
             assert "id" in user_details
             assert "email" in user_details
             assert "full_name" in user_details
+
+    # --- FEATURE FLAG Tests ---
+    @override_settings(FEATURE_MAILDOMAIN_MANAGE_ACCESSES=False)
+    def test_admin_api_maildomain_accesses_create_feature_flag_disabled(
+        self,
+        api_client,
+        super_user,
+        maildomain_1,
+        md1_access,
+        md2_admin_user,
+    ):
+        """Creating access should return 403 when FEATURE_MAILDOMAIN_MANAGE_ACCESSES is False."""
+        api_client.force_authenticate(user=super_user)
+        data = {"user": str(md2_admin_user.pk), "role": "admin"}
+        response = api_client.post(
+            self.list_create_url(maildomain_pk=maildomain_1.pk), data
+        )
+        assert response.status_code == status.HTTP_403_FORBIDDEN
+
+    @override_settings(FEATURE_MAILDOMAIN_MANAGE_ACCESSES=False)
+    def test_admin_api_maildomain_accesses_delete_feature_flag_disabled(
+        self,
+        api_client,
+        super_user,
+        maildomain_1,
+        md1_access,
+    ):
+        """Deleting access should return 403 when FEATURE_MAILDOMAIN_MANAGE_ACCESSES is False."""
+        api_client.force_authenticate(user=super_user)
+        response = api_client.delete(
+            self.detail_url(maildomain_pk=maildomain_1.pk, pk=md1_access.pk)
+        )
+        assert response.status_code == status.HTTP_403_FORBIDDEN
+        assert models.MailDomainAccess.objects.filter(pk=md1_access.pk).exists()
+
+    @override_settings(FEATURE_MAILDOMAIN_MANAGE_ACCESSES=False)
+    def test_admin_api_maildomain_accesses_list_feature_flag_disabled(
+        self,
+        api_client,
+        super_user,
+        maildomain_1,
+        md1_access,
+    ):
+        """Listing accesses should still return 200 when feature flag is disabled (read-only is fine)."""
+        api_client.force_authenticate(user=super_user)
+        response = api_client.get(self.list_create_url(maildomain_pk=maildomain_1.pk))
+        assert response.status_code == status.HTTP_200_OK
diff --git a/src/backend/core/tests/api/test_provisioning_maildomains.py b/src/backend/core/tests/api/test_provisioning_maildomains.py
new file mode 100644
index 000000000..6fc2ed2f7
--- /dev/null
+++ b/src/backend/core/tests/api/test_provisioning_maildomains.py
@@ -0,0 +1,218 @@
+"""Tests for the provisioning maildomains endpoint."""
+# pylint: disable=redefined-outer-name
+
+from django.urls import reverse
+
+import pytest
+
+from core.factories import MailDomainFactory
+from core.models import MailDomain
+
+
+@pytest.fixture
+def url():
+    """Returns the URL for the provisioning maildomains endpoint."""
+    return reverse("provisioning-maildomains")
+
+
+@pytest.fixture
+def auth_header(settings):
+    """Returns the authentication header for the provisioning endpoint."""
+    settings.PROVISIONING_API_KEY = "test-provisioning-key"
+    return {"HTTP_AUTHORIZATION": "Bearer test-provisioning-key"}
+
+
+# -- Authentication tests --
+
+
+@pytest.mark.django_db
+def test_provisioning_no_auth_returns_403(client, url):
+    """Request without Authorization header returns 403."""
+    response = client.post(
+        url, data={"domains": ["test.fr"]}, content_type="application/json"
+    )
+    assert response.status_code == 403
+
+
+@pytest.mark.django_db
+def test_provisioning_wrong_token_returns_403(client, url, settings):
+    """Request with wrong token returns 403."""
+    settings.PROVISIONING_API_KEY = "correct-key"
+    response = client.post(
+        url,
+        data={"domains": ["test.fr"]},
+        content_type="application/json",
+        HTTP_AUTHORIZATION="Bearer wrong-key",
+    )
+    assert response.status_code == 403
+
+
+@pytest.mark.django_db
+def test_provisioning_no_key_configured_returns_403(client, url, settings):
+    """When PROVISIONING_API_KEY is not configured, returns 403."""
+    settings.PROVISIONING_API_KEY = None
+    response = client.post(
+        url,
+        data={"domains": ["test.fr"]},
+        content_type="application/json",
+        HTTP_AUTHORIZATION="Bearer some-key",
+    )
+    assert response.status_code == 403
+
+
+# -- Create tests --
+
+
+@pytest.mark.django_db
+def test_provisioning_creates_domains(client, url, auth_header):
+    """New domains are created with correct custom_attributes."""
+    response = client.post(
+        url,
+        data={
+            "domains": ["domaine.fr", "autre.fr"],
+            "custom_attributes": {"siret": "12345678901234"},
+        },
+        content_type="application/json",
+        **auth_header,
+    )
+    assert response.status_code == 200
+    data = response.json()
+    assert sorted(data["created"]) == ["autre.fr", "domaine.fr"]
+    assert data["existing"] == []
+    assert data["errors"] == []
+
+    for name in ["domaine.fr", "autre.fr"]:
+        domain = MailDomain.objects.get(name=name)
+        assert domain.custom_attributes == {"siret": "12345678901234"}
+
+
+@pytest.mark.django_db
+def test_provisioning_creates_domains_without_custom_attributes(
+    client, url, auth_header
+):
+    """Domains can be created without custom_attributes."""
+    response = client.post(
+        url,
+        data={"domains": ["simple.fr"]},
+        content_type="application/json",
+        **auth_header,
+    )
+    assert response.status_code == 200
+    data = response.json()
+    assert data["created"] == ["simple.fr"]
+
+    domain = MailDomain.objects.get(name="simple.fr")
+    assert domain.custom_attributes == {}
+
+
+# -- Idempotency tests --
+
+
+@pytest.mark.django_db
+def test_provisioning_idempotent_existing_domains(client, url, auth_header):
+    """Existing domains are not duplicated."""
+    MailDomainFactory(name="existing.fr", custom_attributes={"siret": "111"})
+
+    response = client.post(
+        url,
+        data={
+            "domains": ["existing.fr", "new.fr"],
+            "custom_attributes": {"siret": "111"},
+        },
+        content_type="application/json",
+        **auth_header,
+    )
+    assert response.status_code == 200
+    data = response.json()
+    assert data["created"] == ["new.fr"]
+    assert data["existing"] == ["existing.fr"]
+    assert data["errors"] == []
+    assert MailDomain.objects.filter(name="existing.fr").count() == 1
+
+
+@pytest.mark.django_db
+def test_provisioning_updates_custom_attributes_on_existing(client, url, auth_header):
+    """custom_attributes are updated on existing domains when they differ."""
+    MailDomainFactory(name="existing.fr", custom_attributes={"siret": "old"})
+
+    response = client.post(
+        url,
+        data={
+            "domains": ["existing.fr"],
+            "custom_attributes": {"siret": "new"},
+        },
+        content_type="application/json",
+        **auth_header,
+    )
+    assert response.status_code == 200
+    data = response.json()
+    assert data["existing"] == ["existing.fr"]
+
+    domain = MailDomain.objects.get(name="existing.fr")
+    assert domain.custom_attributes == {"siret": "new"}
+
+
+# -- Comma-separated string format --
+
+
+@pytest.mark.django_db
+def test_provisioning_accepts_comma_separated_string(client, url, auth_header):
+    """The endpoint accepts a comma-separated string of domains."""
+    response = client.post(
+        url,
+        data={
+            "domains": "alpha.fr,beta.fr",
+            "custom_attributes": {"siret": "123"},
+        },
+        content_type="application/json",
+        **auth_header,
+    )
+    assert response.status_code == 200
+    data = response.json()
+    assert sorted(data["created"]) == ["alpha.fr", "beta.fr"]
+
+
+# -- Validation tests --
+
+
+@pytest.mark.django_db
+def test_provisioning_invalid_domain_returns_error(client, url, auth_header):
+    """Invalid domain names return structured errors, not 500."""
+    response = client.post(
+        url,
+        data={
+            "domains": ["valid.fr", "INVALID DOMAIN!"],
+            "custom_attributes": {"siret": "123"},
+        },
+        content_type="application/json",
+        **auth_header,
+    )
+    assert response.status_code == 200
+    data = response.json()
+    assert data["created"] == ["valid.fr"]
+    assert len(data["errors"]) == 1
+    assert data["errors"][0]["domain"] == "INVALID DOMAIN!"
+
+
+@pytest.mark.django_db
+def test_provisioning_empty_domains_returns_400(client, url, auth_header):
+    """Empty domains list returns 400."""
+    response = client.post(
+        url,
+        data={"domains": [], "custom_attributes": {"siret": "123"}},
+        content_type="application/json",
+        **auth_header,
+    )
+    assert response.status_code == 400
+
+
+@pytest.mark.django_db
+def test_provisioning_missing_domains_returns_400(client, url, auth_header):
+    """Missing domains field returns 400."""
+    response = client.post(
+        url,
+        data={"custom_attributes": {"siret": "123"}},
+        content_type="application/json",
+        **auth_header,
+    )
+    assert response.status_code == 400
diff --git a/src/backend/core/tests/entitlements/__init__.py b/src/backend/core/tests/entitlements/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/src/backend/core/tests/entitlements/test_backends.py b/src/backend/core/tests/entitlements/test_backends.py
new file mode 100644
index 000000000..605bf4af0
--- /dev/null
+++ b/src/backend/core/tests/entitlements/test_backends.py
@@ -0,0 +1,334 @@
+"""Unit tests for entitlements backends."""
+
+from django.core.cache import cache
+from django.test import override_settings
+
+import pytest
+import requests
+import responses
+
+from core.entitlements import EntitlementsUnavailableError
+from core.entitlements.backends.deploycenter import DeployCenterEntitlementsBackend
+from core.entitlements.backends.local import LocalEntitlementsBackend
+
+
+@pytest.fixture(autouse=True)
+def _clear_cache():
+    cache.clear()
+    yield
+    cache.clear()
+
+
+class TestLocalBackend:
+    """Tests for the LocalEntitlementsBackend."""
+
+    def test_get_user_entitlements(self):
+        """Local backend grants access and returns None for admin domains."""
+        backend = LocalEntitlementsBackend()
+        result = backend.get_user_entitlements("user-sub", "user@example.com")
+        assert result == {
+            "can_access": True,
+            "can_admin_maildomains": None,
+        }
+
+    def test_force_refresh_has_no_effect(self):
+        """force_refresh is accepted but has no effect on local backend."""
+        backend = LocalEntitlementsBackend()
+        result = backend.get_user_entitlements(
+            "user-sub", "user@example.com", force_refresh=True
+        )
+        assert result["can_access"] is True
+
+
+BASE_URL = "https://deploycenter.example.com/api/v1.0/entitlements"
+
+
+class TestDeployCenterBackend:
+    """Tests for the DeployCenterEntitlementsBackend."""
+
+    def _get_backend(self, **kwargs):
+        defaults = {
+            "base_url": BASE_URL,
+            "service_id": "test-service",
+            "api_key": "test-api-key",
+            "timeout": 5,
+        }
+        defaults.update(kwargs)
+        return DeployCenterEntitlementsBackend(**defaults)
+
+    @responses.activate
+    def test_get_user_entitlements_success(self):
+        """Successful API call returns parsed entitlements."""
+        responses.add(
+            responses.GET,
+            BASE_URL,
+            json={
+                "entitlements": {
+                    "can_access": True,
+                    "can_admin_maildomains": ["example.com", "test.org"],
+                },
+            },
+            status=200,
+        )
+
+        backend = self._get_backend()
+        result = backend.get_user_entitlements("user-sub", "user@example.com")
+
+        assert result == {
+            "can_access": True,
+            "can_admin_maildomains": ["example.com", "test.org"],
+        }
+
+    @responses.activate
+    def test_request_params_and_headers(self):
+        """Request includes correct query params and auth header."""
+        responses.add(
+            responses.GET,
+            BASE_URL,
+            json={"entitlements": {"can_access": True}},
+            status=200,
+        )
+
+        backend = self._get_backend()
+        backend.get_user_entitlements("user-sub", "user@example.com")
+
+        request = responses.calls[0].request
+        assert "service_id=test-service" in request.url
+        assert "account_type=user" in request.url
+        assert "account_email=user%40example.com" in request.url
+        assert request.headers["X-Service-Auth"] == "Bearer test-api-key"
+
+    @responses.activate
+    def test_forwards_oidc_claims_as_query_params(self):
+        """Configured OIDC claims from user_info are sent as query params."""
+        responses.add(
+            responses.GET,
+            BASE_URL,
+            json={"entitlements": {"can_access": True}},
+            status=200,
+        )
+
+        backend = self._get_backend(oidc_claims=["siret", "other_claim"])
+        user_info = {"siret": "12345678901234", "other_claim": "value", "ignored": "x"}
+        backend.get_user_entitlements(
+            "user-sub", "user@example.com", user_info=user_info
+        )
+
+        request = responses.calls[0].request
+        assert "siret=12345678901234" in request.url
+        assert "other_claim=value" in request.url
+        assert "ignored" not in request.url
+
+    @responses.activate
+    def test_missing_oidc_claim_not_sent(self):
+        """If a configured claim is absent from user_info, it's just not sent."""
+        responses.add(
+            responses.GET,
+            BASE_URL,
+            json={"entitlements": {"can_access": True}},
+            status=200,
+        )
+
+        backend = self._get_backend(oidc_claims=["siret"])
+        backend.get_user_entitlements(
+            "user-sub", "user@example.com", user_info={"email": "x@y.com"}
+        )
+
+        request = responses.calls[0].request
+        assert "siret" not in request.url
+
+    @responses.activate
+    def test_server_error_raises(self):
+        """Server error raises EntitlementsUnavailableError."""
+        responses.add(responses.GET, BASE_URL, status=500)
+
+        backend = self._get_backend()
+        with pytest.raises(EntitlementsUnavailableError):
+            backend.get_user_entitlements("user-sub", "user@example.com")
+
+    @responses.activate
+    def test_connection_timeout_raises(self):
+        """Connection timeout raises EntitlementsUnavailableError."""
+        responses.add(
+            responses.GET,
+            BASE_URL,
+            body=requests.exceptions.ConnectionError("Connection timed out"),
+        )
+
+        backend = self._get_backend()
+        with pytest.raises(EntitlementsUnavailableError):
+            backend.get_user_entitlements("user-sub", "user@example.com")
+
+    @responses.activate
+    @override_settings(ENTITLEMENTS_CACHE_TIMEOUT=300)
+    def test_cache_hit_returns_cached_without_http(self):
+        """Second call uses cache, no HTTP request made."""
+        responses.add(
+            responses.GET,
+            BASE_URL,
+            json={
+                "entitlements": {
+                    "can_access": True,
+                    "can_admin_maildomains": ["example.com"],
+                },
+            },
+            status=200,
+        )
+
+        backend = self._get_backend()
+        # First call populates cache
+        result1 = backend.get_user_entitlements("user-sub", "user@example.com")
+        # Second call should use cache — no HTTP
+        result2 = backend.get_user_entitlements("user-sub", "user@example.com")
+
+        assert result1 == result2
+        assert len(responses.calls) == 1
+
+    @responses.activate
+    @override_settings(ENTITLEMENTS_CACHE_TIMEOUT=300)
+    def test_force_refresh_bypasses_cache(self):
+        """force_refresh=True makes a new HTTP call even with cached data."""
+        responses.add(
+            responses.GET,
+            BASE_URL,
+            json={"entitlements": {"can_access": True, "can_admin_maildomains": []}},
+            status=200,
+        )
+        responses.add(
+            responses.GET,
+            BASE_URL,
+            json={
+                "entitlements": {
+                    "can_access": True,
+                    "can_admin_maildomains": ["new.com"],
+                },
+            },
+            status=200,
+        )
+
+        backend = self._get_backend()
+        result1 = backend.get_user_entitlements("user-sub", "user@example.com")
+        result2 = backend.get_user_entitlements(
+            "user-sub", "user@example.com", force_refresh=True
+        )
+
+        assert len(responses.calls) == 2
+        assert result1["can_admin_maildomains"] == []
+        assert result2["can_admin_maildomains"] == ["new.com"]
+
+    @responses.activate
+    @override_settings(ENTITLEMENTS_CACHE_TIMEOUT=300)
+    def test_failure_with_stale_cache_returns_cached(self):
+        """When force_refresh fails but stale cache exists, return cached data."""
+        responses.add(
+            responses.GET,
+            BASE_URL,
+            json={
+                "entitlements": {
+                    "can_access": True,
+                    "can_admin_maildomains": ["cached.com"],
+                },
+            },
+            status=200,
+        )
+        # Second call will fail
+        responses.add(responses.GET, BASE_URL, status=500)
+
+        backend = self._get_backend()
+        # Populate cache
+        backend.get_user_entitlements("user-sub", "user@example.com")
+        # Force refresh fails, should fall back to cache
+        result = backend.get_user_entitlements(
+            "user-sub", "user@example.com", force_refresh=True
+        )
+
+        assert result["can_admin_maildomains"] == ["cached.com"]
+        assert len(responses.calls) == 2
+
+    @responses.activate
+    def test_failure_without_cache_raises(self):
+        """API failure with no cache raises EntitlementsUnavailableError."""
+        responses.add(responses.GET, BASE_URL, status=500)
+
+        backend = self._get_backend()
+        with pytest.raises(EntitlementsUnavailableError):
+            backend.get_user_entitlements("user-sub", "user@example.com")
+
+    @responses.activate
+    def test_missing_fields_defaults(self):
+        """Backend should provide sensible defaults for missing response fields."""
+        responses.add(
+            responses.GET,
+            BASE_URL,
+            json={"entitlements": {}},
+            status=200,
+        )
+
+        backend = self._get_backend()
+        result = backend.get_user_entitlements("user-sub", "user@example.com")
+        assert result == {
+            "can_access": False,
+            "can_admin_maildomains": None,
+        }
+
+    @responses.activate
+    def test_missing_entitlements_key(self):
+        """Response with no entitlements key returns safe defaults."""
+        responses.add(responses.GET, BASE_URL, json={}, status=200)
+
+        backend = self._get_backend()
+        result = backend.get_user_entitlements("user-sub", "user@example.com")
+        assert result == {
+            "can_access": False,
+            "can_admin_maildomains": None,
+        }
+
+    @responses.activate
+    @override_settings(ENTITLEMENTS_CACHE_TIMEOUT=300)
+    def test_different_users_have_different_cache_keys(self):
+        """Each user_sub gets its own cache entry."""
+        responses.add(
+            responses.GET,
+            BASE_URL,
+            json={
+                "entitlements": {
+                    "can_access": True,
+                    "can_admin_maildomains": ["a.com"],
+                },
+            },
+            status=200,
+        )
+        responses.add(
+            responses.GET,
+            BASE_URL,
+            json={
+                "entitlements": {
+                    "can_access": False,
+                    "can_admin_maildomains": ["b.com"],
+                },
+            },
+            status=200,
+        )
+
+        backend = self._get_backend()
+        result1 = backend.get_user_entitlements("user1", "user1@example.com")
+        result2 = backend.get_user_entitlements("user2", "user2@example.com")
+
+        assert result1["can_admin_maildomains"] == ["a.com"]
+        assert result2["can_admin_maildomains"] == ["b.com"]
+        assert len(responses.calls) == 2
+
+    @responses.activate
+    def test_invalid_json_response_raises(self):
+        """ValueError from response.json() should be handled."""
+        responses.add(
+            responses.GET,
+            BASE_URL,
+            body="not json",
+            status=200,
+            content_type="text/plain",
+        )
+
+        backend = self._get_backend()
+        with pytest.raises(EntitlementsUnavailableError):
+            backend.get_user_entitlements("user-sub", "user@example.com")
diff --git a/src/backend/core/tests/entitlements/test_oidc_sync.py b/src/backend/core/tests/entitlements/test_oidc_sync.py
new file mode 100644
index 000000000..d5b26abfd
--- /dev/null
+++ b/src/backend/core/tests/entitlements/test_oidc_sync.py
@@ -0,0 +1,290 @@
+"""Tests for entitlements sync during OIDC login."""
+
+from unittest import mock
+
+from django.core.cache import cache
+from django.db import connection
+from django.test.utils import CaptureQueriesContext
+
+import pytest
+
+from core import factories
+from core.authentication.backends import OIDCAuthenticationBackend
+from core.entitlements import EntitlementsUnavailableError
+from core.enums import MailDomainAccessRoleChoices
+from core.models import MailDomainAccess
+
+pytestmark = pytest.mark.django_db
+
+
+@pytest.fixture(autouse=True)
+def _clear_cache():
+    cache.clear()
+    yield
+    cache.clear()
+
+
+class TestSyncEntitlements:  # pylint: disable=protected-access
+    """Tests for _sync_entitlements called during OIDC login."""
+
+    @mock.patch("core.authentication.backends.get_user_entitlements")
+    def test_creates_admin_access_for_entitled_domains(self, mock_get):
+        """Admin access is created for each entitled domain."""
+        user = factories.UserFactory()
+        domain1 = factories.MailDomainFactory(name="domain1.com")
+        domain2 = factories.MailDomainFactory(name="domain2.com")
+
+        mock_get.return_value = {
+            "can_access": True,
+            "can_admin_maildomains": ["domain1.com", "domain2.com"],
+        }
+
+        backend = OIDCAuthenticationBackend()
+        backend._sync_entitlements(user)
+
+        assert MailDomainAccess.objects.filter(
+            user=user, maildomain=domain1, role=MailDomainAccessRoleChoices.ADMIN
+        ).exists()
+        assert MailDomainAccess.objects.filter(
+            user=user, maildomain=domain2, role=MailDomainAccessRoleChoices.ADMIN
+        ).exists()
+
+    @mock.patch("core.authentication.backends.get_user_entitlements")
+    def test_removes_stale_admin_access(self, mock_get):
+        """Admin access for domains no longer entitled is removed."""
+        user = factories.UserFactory()
+        domain1 = factories.MailDomainFactory(name="domain1.com")
+        domain2 = factories.MailDomainFactory(name="domain2.com")
+
+        # User currently has admin access to both domains
+        factories.MailDomainAccessFactory(
+            user=user, maildomain=domain1, role=MailDomainAccessRoleChoices.ADMIN
+        )
+        factories.MailDomainAccessFactory(
+            user=user, maildomain=domain2, role=MailDomainAccessRoleChoices.ADMIN
+        )
+
+        # Entitlements now only include domain1
+        mock_get.return_value = {
+            "can_access": True,
+            "can_admin_maildomains": ["domain1.com"],
+        }
+
+        backend = OIDCAuthenticationBackend()
+        backend._sync_entitlements(user)
+
+        assert MailDomainAccess.objects.filter(user=user, maildomain=domain1).exists()
+        assert not MailDomainAccess.objects.filter(
+            user=user, maildomain=domain2
+        ).exists()
+
+    @mock.patch("core.authentication.backends.get_user_entitlements")
+    def test_skips_sync_when_can_admin_maildomains_is_none(self, mock_get):
+        """If can_admin_maildomains is None (e.g. local backend), skip sync entirely."""
+        user = factories.UserFactory()
+        domain = factories.MailDomainFactory(name="domain.com")
+        factories.MailDomainAccessFactory(
+            user=user, maildomain=domain, role=MailDomainAccessRoleChoices.ADMIN
+        )
+
+        mock_get.return_value = {
+            "can_access": True,
+            "can_admin_maildomains": None,
+        }
+
+        backend = OIDCAuthenticationBackend()
+        backend._sync_entitlements(user)
+
+        # Existing access should still be there
+        assert MailDomainAccess.objects.filter(user=user, maildomain=domain).exists()
+
+    @mock.patch("core.authentication.backends.get_user_entitlements")
+    def test_empty_list_removes_all_admin_accesses(self, mock_get):
+        """An empty list means the user has no admin access to any domain."""
+        user = factories.UserFactory()
+        domain = factories.MailDomainFactory(name="domain.com")
+        factories.MailDomainAccessFactory(
+            user=user, maildomain=domain, role=MailDomainAccessRoleChoices.ADMIN
+        )
+
+        mock_get.return_value = {
+            "can_access": True,
+            "can_admin_maildomains": [],
+        }
+
+        backend = OIDCAuthenticationBackend()
+        backend._sync_entitlements(user)
+
+        assert MailDomainAccess.objects.filter(user=user).count() == 0
+
+    @mock.patch("core.authentication.backends.get_user_entitlements")
+    def test_handles_unavailable_error(self, mock_get):
+        """On EntitlementsUnavailableError, existing accesses are preserved."""
+        user = factories.UserFactory()
+        domain = factories.MailDomainFactory(name="domain.com")
+        factories.MailDomainAccessFactory(
+            user=user, maildomain=domain, role=MailDomainAccessRoleChoices.ADMIN
+        )
+
+        mock_get.side_effect = EntitlementsUnavailableError("Backend down")
+
+        backend = OIDCAuthenticationBackend()
+        backend._sync_entitlements(user)
+
+        # Existing access should NOT be removed
+        assert MailDomainAccess.objects.filter(user=user, maildomain=domain).exists()
+
+    @mock.patch("core.authentication.backends.get_user_entitlements")
+    def test_handles_timeout(self, mock_get):
+        """On timeout (also EntitlementsUnavailableError), existing accesses preserved."""
+        user = factories.UserFactory()
+        domain = factories.MailDomainFactory(name="domain.com")
+        factories.MailDomainAccessFactory(
+            user=user, maildomain=domain, role=MailDomainAccessRoleChoices.ADMIN
+        )
+
+        mock_get.side_effect = EntitlementsUnavailableError("Connection timed out")
+
+        backend = OIDCAuthenticationBackend()
+        backend._sync_entitlements(user)
+
+        assert MailDomainAccess.objects.filter(user=user, maildomain=domain).exists()
+
+    @mock.patch("core.authentication.backends.get_user_entitlements")
+    def test_skips_nonexistent_domains(self, mock_get):
+        """Domains not present in the DB are silently skipped."""
+        user = factories.UserFactory()
+
+        mock_get.return_value = {
+            "can_access": True,
+            "can_admin_maildomains": ["nonexistent.com"],
+        }
+
+        backend = OIDCAuthenticationBackend()
+        backend._sync_entitlements(user)
+
+        assert MailDomainAccess.objects.filter(user=user).count() == 0
+
+    @mock.patch("core.authentication.backends.get_user_entitlements")
+    def test_does_not_duplicate_existing_access(self, mock_get):
+        """Should not create duplicate MailDomainAccess records."""
+        user = factories.UserFactory()
+        domain = factories.MailDomainFactory(name="domain.com")
+        factories.MailDomainAccessFactory(
+            user=user, maildomain=domain, role=MailDomainAccessRoleChoices.ADMIN
+        )
+
+        mock_get.return_value = {
+            "can_access": True,
+            "can_admin_maildomains": ["domain.com"],
+        }
+
+        backend = OIDCAuthenticationBackend()
+        backend._sync_entitlements(user)
+
+        assert (
+            MailDomainAccess.objects.filter(user=user, maildomain=domain).count() == 1
+        )
+
+    @mock.patch("core.authentication.backends.get_user_entitlements")
+    def test_force_refresh_is_used(self, mock_get):
+        """Should call get_user_entitlements with force_refresh=True."""
+        user = factories.UserFactory()
+
+        mock_get.return_value = {
+            "can_access": True,
+            "can_admin_maildomains": [],
+        }
+
+        backend = OIDCAuthenticationBackend()
+        backend._sync_entitlements(user)
+
+        mock_get.assert_called_once_with(
+            user.sub, user.email, user_info=None, force_refresh=True
+        )
+
+    @mock.patch("core.authentication.backends.get_user_entitlements")
+    def test_passes_user_info_from_oidc(self, mock_get):
+        """Should forward the stored OIDC user_info to get_user_entitlements."""
+        user = factories.UserFactory()
+        user_info = {"sub": user.sub, "email": user.email, "siret": "12345678901234"}
+
+        mock_get.return_value = {
+            "can_access": True,
+            "can_admin_maildomains": [],
+        }
+
+        backend = OIDCAuthenticationBackend()
+        backend._user_info = user_info
+        backend._sync_entitlements(user)
+
+        mock_get.assert_called_once_with(
+            user.sub, user.email, user_info=user_info, force_refresh=True
+        )
+
+    @mock.patch("core.authentication.backends.get_user_entitlements")
+    def test_optimistic_path_no_db_writes_when_in_sync(self, mock_get):
+        """When entitled domains match existing accesses, no DB writes should occur."""
+        user = factories.UserFactory()
+        domain = factories.MailDomainFactory(name="domain.com")
+        factories.MailDomainAccessFactory(
+            user=user, maildomain=domain, role=MailDomainAccessRoleChoices.ADMIN
+        )
+
+        mock_get.return_value = {
+            "can_access": True,
+            "can_admin_maildomains": ["domain.com"],
+        }
+
+        backend = OIDCAuthenticationBackend()
+
+        with CaptureQueriesContext(connection) as ctx:
+            backend._sync_entitlements(user)
+
+        # Only SELECT queries (no INSERT, UPDATE, DELETE)
+        write_queries = [
+            q
+            for q in ctx.captured_queries
+            if q["sql"].startswith(("INSERT", "UPDATE", "DELETE"))
+        ]
+        assert write_queries == []
+        assert (
+            MailDomainAccess.objects.filter(user=user, maildomain=domain).count() == 1
+        )
+
+    @mock.patch("core.authentication.backends.get_user_entitlements")
+    def test_login_resets_cache(self, mock_get):
+        """Logging in should call with force_refresh=True, resetting cached data."""
+        user = factories.UserFactory()
+
+        # Simulate first login with domains
+        mock_get.return_value = {
+            "can_access": True,
+            "can_admin_maildomains": ["first.com"],
+        }
+        factories.MailDomainFactory(name="first.com")
+
+        backend = OIDCAuthenticationBackend()
+        backend._sync_entitlements(user)
+
+        # Simulate second login with different domains
+        mock_get.return_value = {
+            "can_access": True,
+            "can_admin_maildomains": ["second.com"],
+        }
+        factories.MailDomainFactory(name="second.com")
+
+        backend._sync_entitlements(user)
+
+        # Both calls should have force_refresh=True
+        assert mock_get.call_count == 2
+        for call in mock_get.call_args_list:
+            assert call.kwargs.get("force_refresh") is True
+
+        # Only second.com should remain
+        assert not MailDomainAccess.objects.filter(
+            user=user, maildomain__name="first.com"
+        ).exists()
+        assert MailDomainAccess.objects.filter(
+            user=user, maildomain__name="second.com"
+        ).exists()
diff --git a/src/backend/core/urls.py b/src/backend/core/urls.py
index b7fb5bf56..cb482f4d4 100644
--- a/src/backend/core/urls.py
+++ b/src/backend/core/urls.py
@@ -37,6 +37,7 @@
     MailDomainUsersMetricsApiView,
 )
 from core.api.viewsets.placeholder import DraftPlaceholderView, PlaceholderView
+from core.api.viewsets.provisioning import ProvisioningMailDomainView
 from core.api.viewsets.send import SendMessageView
 from core.api.viewsets.task import TaskDetailView
 from core.api.viewsets.thread import ThreadViewSet
@@ -241,6 +242,11 @@
         MailboxUsageMetricsApiView.as_view(),
         name="mailbox-usage-metrics",
     ),
+    path(
+        f"api/{settings.API_VERSION}/provisioning/maildomains/",
+        ProvisioningMailDomainView.as_view(),
+        name="provisioning-maildomains",
+    ),
     # Alias for MTA check endpoint
     path(
         f"api/{settings.API_VERSION}/mta/check-recipients/",
diff --git a/src/backend/messages/settings.py b/src/backend/messages/settings.py
index 66c9cad34..83cf9da02 100755
--- a/src/backend/messages/settings.py
+++ b/src/backend/messages/settings.py
@@ -789,6 +789,10 @@ class Base(Configuration):
         None, environ_name="METRICS_API_KEY", environ_prefix=None
     )
 
+    PROVISIONING_API_KEY = values.Value(
+        None, environ_name="PROVISIONING_API_KEY", environ_prefix=None
+    )
+
     METRICS_STORAGE_USED_OVERHEAD_BY_MESSAGE = values.PositiveIntegerValue(
         1024,
         environ_name="METRICS_STORAGE_USED_OVERHEAD_BY_MESSAGE",
@@ -800,6 +804,19 @@ class Base(Configuration):
     AI_BASE_URL = values.Value(None, environ_name="AI_BASE_URL", environ_prefix=None)
     AI_MODEL = values.Value(None, environ_name="AI_MODEL", environ_prefix=None)
 
+    # Entitlements
+    ENTITLEMENTS_BACKEND = values.Value(
+        "core.entitlements.backends.local.LocalEntitlementsBackend",
+        environ_name="ENTITLEMENTS_BACKEND",
+        environ_prefix=None,
+    )
+    ENTITLEMENTS_BACKEND_PARAMETERS = JSONValue(
+        {}, environ_name="ENTITLEMENTS_BACKEND_PARAMETERS", environ_prefix=None
+    )
+    ENTITLEMENTS_CACHE_TIMEOUT = values.PositiveIntegerValue(
+        300, environ_name="ENTITLEMENTS_CACHE_TIMEOUT", environ_prefix=None
+    )
+
     # Feature flags
     FEATURE_AI_SUMMARY = values.BooleanValue(
         default=False, environ_name="FEATURE_AI_SUMMARY", environ_prefix=None
@@ -816,6 +833,14 @@ class Base(Configuration):
     FEATURE_MAILBOX_ADMIN_CHANNELS = values.ListValue(
         default=[], environ_name="FEATURE_MAILBOX_ADMIN_CHANNELS", environ_prefix=None
     )
+    FEATURE_MAILDOMAIN_CREATE = values.BooleanValue(
+        default=True, environ_name="FEATURE_MAILDOMAIN_CREATE", environ_prefix=None
+    )
+    FEATURE_MAILDOMAIN_MANAGE_ACCESSES = values.BooleanValue(
+        default=True,
+        environ_name="FEATURE_MAILDOMAIN_MANAGE_ACCESSES",
+        environ_prefix=None,
+    )
 
     # Logging
     # We want to make it easy to log to console but by default we log production
diff --git a/src/frontend/src/features/api/gen/models/config_retrieve200.ts b/src/frontend/src/features/api/gen/models/config_retrieve200.ts
index 508e0595d..41d639be7 100644
--- a/src/frontend/src/features/api/gen/models/config_retrieve200.ts
+++ b/src/frontend/src/features/api/gen/models/config_retrieve200.ts
@@ -33,6 +33,8 @@ export type ConfigRetrieve200 = {
   readonly MAX_TEMPLATE_IMAGE_SIZE: number;
   /** Whether external images should be proxied */
   readonly IMAGE_PROXY_ENABLED: boolean;
+  readonly FEATURE_MAILDOMAIN_CREATE: boolean;
+  readonly FEATURE_MAILDOMAIN_MANAGE_ACCESSES: boolean;
   /** Maximum age in seconds for a message to be eligible for manual retry of failed deliveries */
   readonly MESSAGES_MANUAL_RETRY_MAX_AGE: number;
 };
diff --git a/src/frontend/src/features/layouts/components/admin/domains-view/create-domain-action.tsx b/src/frontend/src/features/layouts/components/admin/domains-view/create-domain-action.tsx
index 8cb4cc2f0..fe74afdad 100644
--- a/src/frontend/src/features/layouts/components/admin/domains-view/create-domain-action.tsx
+++ b/src/frontend/src/features/layouts/components/admin/domains-view/create-domain-action.tsx
@@ -1,6 +1,7 @@
 import { MailDomainAdminWrite } from "@/features/api/gen";
 import { ModalCreateDomain } from "@/features/layouts/components/admin/modal-create-domain";
 import useAbility, { Abilities } from "@/hooks/use-ability";
+import { FEATURE_KEYS, useFeatureFlag } from "@/hooks/use-feature";
 import { Button, useModal } from "@gouvfr-lasuite/cunningham-react";
 import { useTranslation } from "react-i18next";
 
@@ -16,8 +17,9 @@ export const CreateDomainAction = ({ onCreate }: CreateDomainActionProps) => {
     const modal = useModal();
     const { t } = useTranslation();
     const canCreateDomains = useAbility(Abilities.CAN_CREATE_MAILDOMAINS);
+    const isFeatureEnabled = useFeatureFlag(FEATURE_KEYS.MAILDOMAIN_CREATE);
 
-    if (!canCreateDomains) {
+    if (!canCreateDomains || !isFeatureEnabled) {
         return null;
     }
 
diff --git a/src/frontend/src/features/providers/config.tsx b/src/frontend/src/features/providers/config.tsx
index 242d2af3d..d8a7c3338 100644
--- a/src/frontend/src/features/providers/config.tsx
+++ b/src/frontend/src/features/providers/config.tsx
@@ -27,6 +27,8 @@ const DEFAULT_CONFIG: AppConfig = {
     MAX_RECIPIENTS_PER_MESSAGE: 0,
     MAX_TEMPLATE_IMAGE_SIZE: 0,
     IMAGE_PROXY_ENABLED: false,
+    FEATURE_MAILDOMAIN_CREATE: true,
+    FEATURE_MAILDOMAIN_MANAGE_ACCESSES: true,
     DRIVE: DEFAULT_DRIVE_CONFIG,
     MESSAGES_MANUAL_RETRY_MAX_AGE: 0,
 }
diff --git a/src/frontend/src/hooks/use-feature.ts b/src/frontend/src/hooks/use-feature.ts
index 8ed7ce5b4..125692875 100644
--- a/src/frontend/src/hooks/use-feature.ts
+++ b/src/frontend/src/hooks/use-feature.ts
@@ -5,6 +5,8 @@ export enum FEATURE_KEYS {
     AI_SUMMARY = 'ai_summary',
     AI_AUTOLABELS = 'ai_autolabels',
     MAILBOX_ADMIN_CHANNELS = 'mailbox_admin_channels',
+    MAILDOMAIN_CREATE = 'maildomain_create',
+    MAILDOMAIN_MANAGE_ACCESSES = 'maildomain_manage_accesses',
 }
 
 /**
@@ -26,6 +28,10 @@ export const useFeatureFlag = (featureKey: FEATURE_KEYS) => {
             return config.AI_ENABLED === true && config.FEATURE_AI_AUTOLABELS === true;
         case FEATURE_KEYS.MAILBOX_ADMIN_CHANNELS:
             return Array.isArray(config.FEATURE_MAILBOX_ADMIN_CHANNELS) && config.FEATURE_MAILBOX_ADMIN_CHANNELS.length > 0;
+        case FEATURE_KEYS.MAILDOMAIN_CREATE:
+            return config.FEATURE_MAILDOMAIN_CREATE === true;
+        case FEATURE_KEYS.MAILDOMAIN_MANAGE_ACCESSES:
+            return config.FEATURE_MAILDOMAIN_MANAGE_ACCESSES === true;
         default:
             throw new Error(`Unknown feature key: ${featureKey}`);
     }
diff --git a/src/frontend/src/pages/domain/index.tsx b/src/frontend/src/pages/domain/index.tsx
index 671ba4dc6..f8da85804 100644
--- a/src/frontend/src/pages/domain/index.tsx
+++ b/src/frontend/src/pages/domain/index.tsx
@@ -7,6 +7,7 @@ import { AdminLayout } from "@/features/layouts/components/admin/admin-layout";
 import { getMaildomainsListQueryOptions, MailDomainAdmin, MailDomainAdminWrite } from "@/features/api/gen";
 import { useAdminMailDomain } from "@/features/providers/admin-maildomain";
 import useAbility, { Abilities } from "@/hooks/use-ability";
+import { FEATURE_KEYS, useFeatureFlag } from "@/hooks/use-feature";
 import { Banner } from "@/features/ui/components/banner";
 import { CreateDomainAction } from "@/features/layouts/components/admin/domains-view/create-domain-action";
 import { useQueryClient } from "@tanstack/react-query";
@@ -25,7 +26,9 @@ enum MailDomainEditAction {
 function AdminDataGrid({ domains, pagination }: AdminDataGridProps) {
   const router = useRouter();
   const { t, i18n } = useTranslation();
-  const canManageMaildomainAccesses = useAbility(Abilities.CAN_MANAGE_SOME_MAILDOMAIN_ACCESSES);
+  const hasManageAbility = useAbility(Abilities.CAN_MANAGE_SOME_MAILDOMAIN_ACCESSES);
+  const isManageAccessesEnabled = useFeatureFlag(FEATURE_KEYS.MAILDOMAIN_MANAGE_ACCESSES);
+  const canManageMaildomainAccesses = hasManageAbility && isManageAccessesEnabled;
   const [editedDomain, setEditedDomain] = useState<MailDomainAdmin | null>(null);
   const [editAction, setEditAction] = useState<MailDomainEditAction | null>(null);
   const columns = [
@@ -95,7 +98,9 @@ const AdminPageContent = () => {
   const { t } = useTranslation();
   const { mailDomains, isLoading, error, pagination } = useAdminMailDomain();
   const canCreateMaildomain = useAbility(Abilities.CAN_CREATE_MAILDOMAINS);
-  const canManageMaildomainAccesses = useAbility(Abilities.CAN_MANAGE_SOME_MAILDOMAIN_ACCESSES);
+  const hasManageAbility = useAbility(Abilities.CAN_MANAGE_SOME_MAILDOMAIN_ACCESSES);
+  const isManageAccessesEnabled = useFeatureFlag(FEATURE_KEYS.MAILDOMAIN_MANAGE_ACCESSES);
+  const canManageMaildomainAccesses = hasManageAbility && isManageAccessesEnabled;
   const shouldRedirect = !canCreateMaildomain && !canManageMaildomainAccesses && !isLoading && mailDomains.length === 1;
 
   /**