diff --git a/.gitignore b/.gitignore
index 2be0351..57bdb06 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 *.pyc
+.env
 /__pycache__/
diff --git a/README.md b/README.md
index 8643e7f..89e4288 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,7 @@ No Masters edition of Keycloak.
   - They are valid for 30 days by default (configurable via `INVITE_TIME_LIMIT`)
   - Anyone with an invite link can create an account on the Keycloak, so don't share publicly!
   - There is no access granularity on the account creation implemented yet, so the accounts are "global"
+    - **New**: it is possible to only allow "admins" to log in, see [feature flags](#feature-flags)
   - Once the user fills in their name, email, password they will receive an email verification mail
 
 If you want a feature implemented, please open an issue to discuss.
@@ -60,6 +61,32 @@ your technology stack.
 - Log in with your usual login details
 - Follow the instructions on the web page to perform administrative actions
 
+## Feature Flags
+
+### Only admins can log in
+
+#### Keycloak
+
+- Create a new group under `Groups` called `Administrators` (case sensistive!)
+- Create a new scope under `Client scopes`
+  - Name: `groups`
+  - Type: `Optional`
+  - Include in token scope: `yes`
+- Under the `Mappers` tab of this client scope, choose `Add mapper`
+  - Mapper type/Name: `Groups Membership`
+  - Token claim name: `groups`
+  - Add to ID token: `yes`
+  - Add to access token: `yes`
+  - Add to userinfo: `yes`
+- Add this client scope to your `admin-cli` client as `Optional`
+- Add a test user to this group under `Users`
+
+#### Keycloak Community Portal
+
+- Set `FEATURE_FLAG_ADMINS_ONLY=True` in your `.env`
+- You may want to customise `KEYCLOAK_GROUPS_KEY` / `KEYCLOAK_ADMINS_GROUP` if
+  you changed the value of `groups` / `Administrators` above
+
 ## Hacking
 
 It's a [FastAPI](https://fastapi.tiangolo.com/) application (if you know
diff --git a/keycloak_collective_portal/config.py b/keycloak_collective_portal/config.py
index 8cb53de..00afd85 100644
--- a/keycloak_collective_portal/config.py
+++ b/keycloak_collective_portal/config.py
@@ -12,7 +12,9 @@ KEYCLOAK_CLIENT_ID = environ.get("KEYCLOAK_CLIENT_ID")
 KEYCLOAK_CLIENT_SECRET = environ.get("KEYCLOAK_CLIENT_SECRET")
 KEYCLOAK_DOMAIN = environ.get("KEYCLOAK_DOMAIN")
 KEYCLOAK_REALM = environ.get("KEYCLOAK_REALM")
-KEYCLOAK_SCOPES = environ.get("KEYCLOAK_SCOPES", "openid profile email")
+KEYCLOAK_SCOPES = environ.get("KEYCLOAK_SCOPES", "openid profile email groups")
+KEYCLOAK_GROUPS_KEY = environ.get("KEYCLOAK_GROUPS_KEY", "groups")
+KEYCLOAK_ADMINS_GROUP = environ.get("KEYCLOAK_ADMINS_GROUP", "Administrators")
 KEYCLOAK_BASE_URL = f"https://{KEYCLOAK_DOMAIN}/realms/{KEYCLOAK_REALM}/protocol/openid-connect"  # noqa
 
 # Redis connection details, our main storage
@@ -39,5 +41,15 @@ elif LOG_LEVEL == "debug":
 else:
     APP_LOG_LEVEL = logging.INFO
 
+
+def to_bool(env_var):
+    """Parse a bool from the environment."""
+    return environ.get(env_var, "False").lower() in ("true", "1", "t")
+
+
 # Automatically log folks in or show the default log in page?
-AUTOMATICALLY_LOG_IN = environ.get("AUTOMATICALLY_LOG_IN", False)
+AUTOMATICALLY_LOG_IN = to_bool("AUTOMATICALLY_LOG_IN")
+
+# Feature flags
+# Only admins can log in to the interface
+FEATURE_FLAG_ADMINS_ONLY = to_bool("FEATURE_FLAG_ADMINS_ONLY")
diff --git a/keycloak_collective_portal/routes/root.py b/keycloak_collective_portal/routes/root.py
index eb2a806..1785fbc 100644
--- a/keycloak_collective_portal/routes/root.py
+++ b/keycloak_collective_portal/routes/root.py
@@ -15,7 +15,26 @@ router = APIRouter()
 async def home(
     request: Request, user=Depends(get_user), invites=Depends(get_invites)
 ):
+    from keycloak_collective_portal.config import (
+        FEATURE_FLAG_ADMINS_ONLY,
+        KEYCLOAK_ADMINS_GROUP,
+        KEYCLOAK_GROUPS_KEY,
+    )
+
     context = {"request": request, "user": user, "invites": invites}
+
+    if FEATURE_FLAG_ADMINS_ONLY:
+        context["message"] = "only admins can access this service"
+        if KEYCLOAK_GROUPS_KEY not in user:
+            return request.app.state.templates.TemplateResponse(
+                "invalid.html", context=context
+            )
+
+        if KEYCLOAK_ADMINS_GROUP not in user[KEYCLOAK_GROUPS_KEY]:
+            return request.app.state.templates.TemplateResponse(
+                "invalid.html", context=context
+            )
+
     return request.app.state.templates.TemplateResponse(
         "admin.html", context=context
     )