diff --git a/dlx_rest/api/__init__.py b/dlx_rest/api/__init__.py
index 7663631f..03905a02 100644
--- a/dlx_rest/api/__init__.py
+++ b/dlx_rest/api/__init__.py
@@ -1640,8 +1640,8 @@ def get(self):
             abort(404, 'Maximum limit is 1000')
         
         if args.identifier:
-            if args.identifierType:
-                this_identifier = Identifier(args.identifierType, args.identifier)
+            if args.identifier_type:
+                this_identifier = Identifier(args.identifier_type, args.identifier)
 
                 if args.language:
                     # Get files for identifier by language
@@ -1650,9 +1650,9 @@ def get(self):
                     # Get all files for that identifier
                     data = [URL('api_file_record', record_id=f.id).to_str() for f in File.find_by_identifier(this_identifier)]
             else:
-                abort(404, 'Param "identifierType" required with param "identifier"')
-        elif args.identifierType and not args.identifier:
-            abort(404, 'Param "identifier" required with param "identifierType"')
+                abort(404, 'Param "identifier_type" required with param "identifier"')
+        elif args.identifier_type and not args.identifier:
+            abort(404, 'Param "identifier" required with param "identifier_type"')
         else:
             data = [URL('api_file_record', record_id=f.id).to_str() for f in File.find({}, skip=start - 1, limit=limit)]
         
diff --git a/dlx_rest/tests/test_api.py b/dlx_rest/tests/test_api.py
index 66ed4250..36fbb856 100644
--- a/dlx_rest/tests/test_api.py
+++ b/dlx_rest/tests/test_api.py
@@ -695,11 +695,11 @@ def test_api_files(client, files):
     data = check_response(res)
     assert f'{API}/files/f20d9f2072bbeb6691c0f9c5099b01f3' in data['data']
 
-    res = client.get(f'{API}/files?identifierType=isbn&identifier=x')
+    res = client.get(f'{API}/files?identifier_type=isbn&identifier=x')
     data = check_response(res)
     assert f'{API}/files/f20d9f2072bbeb6691c0f9c5099b01f3' in data['data']
 
-    res = client.get(f'{API}/files?identifierType=isbn&identifier=x&language=en')
+    res = client.get(f'{API}/files?identifier_type=isbn&identifier=x&language=en')
     data = check_response(res)
     assert f'{API}/files/f20d9f2072bbeb6691c0f9c5099b01f3' in data['data']