diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/config/__init__.py b/spiffworkflow-backend/src/spiffworkflow_backend/config/__init__.py
index e519599c9..d300acd23 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/config/__init__.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/config/__init__.py
@@ -234,6 +234,7 @@ def setup_config(app: Flask) -> None:
                 "uri": app.config.get("SPIFFWORKFLOW_BACKEND_OPEN_ID_SERVER_URL"),
                 "client_id": app.config.get("SPIFFWORKFLOW_BACKEND_OPEN_ID_CLIENT_ID"),
                 "client_secret": app.config.get("SPIFFWORKFLOW_BACKEND_OPEN_ID_CLIENT_SECRET_KEY"),
+                "additional_valid_client_ids": app.config.get("SPIFFWORKFLOW_BACKEND_OPEN_ID_ADDITIONAL_VALID_CLIENT_IDS"),
             }
         ]
 
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/config/default.py b/spiffworkflow-backend/src/spiffworkflow_backend/config/default.py
index 019481632..91deaacaf 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/config/default.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/config/default.py
@@ -106,6 +106,15 @@ else:
         SPIFFWORKFLOW_BACKEND_OPEN_ID_SERVER_URL = url_config
         config_from_env("SPIFFWORKFLOW_BACKEND_OPEN_ID_CLIENT_ID", default="spiffworkflow-backend")
         config_from_env("SPIFFWORKFLOW_BACKEND_OPEN_ID_CLIENT_SECRET_KEY", default="JXeQExm0JhQPLumgHtIIqf52bDalHz0q")
+
+        # comma-separated list of client ids that can be successfully validated against.
+        # useful for api users that will login to a different client on the same realm but from something external to backend.
+        # Example:
+        #       client-A is configured as the main client id in backend
+        #       client-B is for api users who will authenticate directly with keycloak
+        #       if client-B is added to this list, then an api user can auth with keycloak
+        #           and use that token successfully with backend
+        config_from_env("SPIFFWORKFLOW_BACKEND_OPEN_ID_ADDITIONAL_VALID_CLIENT_IDS")
     else:
         SPIFFWORKFLOW_BACKEND_AUTH_CONFIGS = [
             {
@@ -114,6 +123,7 @@ else:
                 "uri": "http://localhost:7002/realms/spiffworkflow",
                 "client_id": "spiffworkflow-backend",
                 "client_secret": "JXeQExm0JhQPLumgHtIIqf52bDalHz0q",
+                "additional_valid_client_ids": None,
             }
         ]
 
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/services/authentication_service.py b/spiffworkflow-backend/src/spiffworkflow_backend/services/authentication_service.py
index 2f2423e0f..f12860983 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/services/authentication_service.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/services/authentication_service.py
@@ -1,11 +1,18 @@
 import base64
 import enum
 import json
+import sys
 import time
 from hashlib import sha256
 from hmac import HMAC
 from hmac import compare_digest
-from typing import TypedDict
+
+if sys.version_info < (3, 11):
+    from typing_extensions import NotRequired
+    from typing_extensions import TypedDict
+else:
+    from typing import NotRequired
+    from typing import TypedDict
 
 import jwt
 import requests
@@ -36,6 +43,7 @@ class AuthenticationOptionForApi(TypedDict):
     identifier: str
     label: str
     uri: str
+    additional_valid_client_ids: NotRequired[str]
 
 
 class AuthenticationOption(AuthenticationOptionForApi):
@@ -163,6 +171,24 @@ class AuthenticationService:
         auth_token_object: dict = json.loads(response.text)
         return auth_token_object
 
+    @classmethod
+    def is_valid_azp(cls, authentication_identifier: str, azp: str | None) -> bool:
+        # not all open id token include an azp so only check if present
+        if azp is None:
+            return True
+
+        valid_client_ids = [cls.client_id(authentication_identifier), "account"]
+        if (
+            "additional_valid_client_ids" in cls.authentication_option_for_identifier(authentication_identifier)
+            and cls.authentication_option_for_identifier(authentication_identifier)["additional_valid_client_ids"] is not None
+        ):
+            additional_valid_client_ids = cls.authentication_option_for_identifier(authentication_identifier)[
+                "additional_valid_client_ids"
+            ].split(",")
+            additional_valid_client_ids = [value.strip() for value in additional_valid_client_ids]
+            valid_client_ids = valid_client_ids + additional_valid_client_ids
+        return azp in valid_client_ids
+
     @classmethod
     def validate_id_or_access_token(cls, token: str, authentication_identifier: str) -> bool:
         """Https://openid.net/specs/openid-connect-core-1_0.html#IDTokenValidation."""
@@ -198,10 +224,7 @@ class AuthenticationService:
                 f"TOKEN INVALID because audience '{aud}' does not match client id '{cls.client_id(authentication_identifier)}'"
             )
             valid = False
-        elif azp and azp not in (
-            cls.client_id(authentication_identifier),
-            "account",
-        ):
+        elif not cls.is_valid_azp(authentication_identifier, azp):
             current_app.logger.error(
                 f"TOKEN INVALID because azp '{azp}' does not match client id '{cls.client_id(authentication_identifier)}'"
             )