diff --git a/README.md b/README.md
index f8618c5..fe8d4e1 100644
--- a/README.md
+++ b/README.md
@@ -70,12 +70,16 @@ The server can be configured on start up using environment variables or at runti
 
 ### Environment variables
 
-Use the following environment variables to create a user on start up:
-
-| Name                  | Value           |
-|-----------------------|-----------------|
-| FLASK_OIDC_USER_ID    | OIDC user id    |
-| FLASK_OIDC_USER_EMAIL | OIDC user email |
+Use the following environment variables to create a user and register a client on start up:
+
+| Name                           | Value                    |
+|--------------------------------|--------------------------|
+| FLASK_OIDC_USER_ID             | OIDC user id             |
+| FLASK_OIDC_USER_EMAIL          | OIDC user email          |
+| FLASK_OIDC_CLIENT_ID           | OIDC client id           |
+| FLASK_OIDC_CLIENT_REDIRECT_URI | OIDC client redirect URI |
+| FLASK_OIDC_CLIENT_PUBLIC_KEY   | OIDC client public key   |
+| FLASK_OIDC_CLIENT_SCOPE        | OIDC client scope        |
 
 ### Web API
 
diff --git a/oidc_server/app.py b/oidc_server/app.py
index e1c5572..b2a01cd 100644
--- a/oidc_server/app.py
+++ b/oidc_server/app.py
@@ -99,6 +99,16 @@ def create_app(test_config: dict[str, Any] | None = None) -> OidcServerApp:
     if "OIDC_USER_ID" in app.config:
         app.add_user(StubUser(id=app.config["OIDC_USER_ID"], email=app.config["OIDC_USER_EMAIL"]))
 
+    if "OIDC_CLIENT_ID" in app.config:
+        app.add_client(
+            StubClient(
+                client_id=app.config["OIDC_CLIENT_ID"],
+                redirect_uri=app.config["OIDC_CLIENT_REDIRECT_URI"],
+                public_key=app.config["OIDC_CLIENT_PUBLIC_KEY"],
+                scope=app.config["OIDC_CLIENT_SCOPE"],
+            )
+        )
+
     key = RSAKey.generate_key(is_private=True)
     authorization_server = app.create_authorization_server(key)
     require_oauth = app.create_resource_protector()