diff --git a/src/imednet/endpoints/registry.py b/src/imednet/endpoints/registry.py
index 5f8e5beb..169fab0f 100644
--- a/src/imednet/endpoints/registry.py
+++ b/src/imednet/endpoints/registry.py
@@ -7,7 +7,8 @@
 
 from __future__ import annotations
 
-from typing import Dict, Type
+from types import MappingProxyType
+from typing import Mapping, Type
 
 from imednet.core.endpoint.base import GenericEndpoint
 from imednet.endpoints.codings import CodingsEndpoint
@@ -24,18 +25,20 @@
 from imednet.endpoints.variables import VariablesEndpoint
 from imednet.endpoints.visits import VisitsEndpoint
 
-ENDPOINT_REGISTRY: Dict[str, Type[GenericEndpoint]] = {
-    "codings": CodingsEndpoint,
-    "forms": FormsEndpoint,
-    "intervals": IntervalsEndpoint,
-    "jobs": JobsEndpoint,
-    "queries": QueriesEndpoint,
-    "record_revisions": RecordRevisionsEndpoint,
-    "records": RecordsEndpoint,
-    "sites": SitesEndpoint,
-    "studies": StudiesEndpoint,
-    "subjects": SubjectsEndpoint,
-    "users": UsersEndpoint,
-    "variables": VariablesEndpoint,
-    "visits": VisitsEndpoint,
-}
+ENDPOINT_REGISTRY: Mapping[str, Type[GenericEndpoint]] = MappingProxyType(
+    {
+        "codings": CodingsEndpoint,
+        "forms": FormsEndpoint,
+        "intervals": IntervalsEndpoint,
+        "jobs": JobsEndpoint,
+        "queries": QueriesEndpoint,
+        "record_revisions": RecordRevisionsEndpoint,
+        "records": RecordsEndpoint,
+        "sites": SitesEndpoint,
+        "studies": StudiesEndpoint,
+        "subjects": SubjectsEndpoint,
+        "users": UsersEndpoint,
+        "variables": VariablesEndpoint,
+        "visits": VisitsEndpoint,
+    }
+)