diff --git a/bento_lib/config/pydantic.py b/bento_lib/config/pydantic.py
index bbf8988..6db56d6 100644
--- a/bento_lib/config/pydantic.py
+++ b/bento_lib/config/pydantic.py
@@ -4,7 +4,7 @@
 from bento_lib.service_info.constants import SERVICE_ORGANIZATION_C3G
 from bento_lib.service_info.types import GA4GHServiceOrganizationModel
 from pydantic.fields import FieldInfo
-from pydantic_settings import BaseSettings, EnvSettingsSource, PydanticBaseSettingsSource
+from pydantic_settings import BaseSettings, EnvSettingsSource, PydanticBaseSettingsSource, SettingsConfigDict
 from typing import Any
 
 __all__ = [
@@ -41,6 +41,9 @@ class BentoBaseConfig(BaseSettings):
 
     cors_origins: tuple[str, ...] = CORS_ORIGINS_DEFAULT
 
+    # Make Config instances hashable + immutable
+    model_config = SettingsConfigDict(frozen=True)
+
     @classmethod
     def settings_customise_sources(
         cls,