diff --git a/src/app.py b/src/app.py
index 09138734..c20b04ea 100644
--- a/src/app.py
+++ b/src/app.py
@@ -2316,9 +2316,8 @@ def validate_constraints():
     if not request.is_json:
         bad_request_error("A json body and appropriate Content-Type header are required")
     json_entry = request.get_json()
-    is_valid = constraints_json_is_valid(json_entry)
-    if is_valid is not True:
-        bad_request_error(is_valid)
+    if not isinstance(json_entry, list):
+        return "JSON body expects a list."
     is_match = request.values.get('match')
     order = request.values.get('order')
 
@@ -2329,9 +2328,7 @@ def validate_constraints():
         'name': "ok"
     }
 
-    index = 0
     for constraint in json_entry:
-        index += 1
         if order == 'descendants':
             result = get_constraints(constraint, 'descendants', 'ancestors', is_match)
         else:
@@ -4599,35 +4596,6 @@ def internal_server_error(err_msg):
     abort(500, description = err_msg)
 
 
-"""
-Validates the incoming json for the endpoint /constraints. 
-Returns true if the json matches the required format. If 
-invalid, returns a string explaining why.
-"""
-def constraints_json_is_valid(json_entry):
-    if not isinstance(json_entry, list):
-        return "JSON body expects a list."
-    
-    for constraint in json_entry:
-        if not isinstance(constraint, dict):
-            return "Each constraint in the list must be a JSON object."
-
-        for key in constraint:
-            if key not in ["ancestors", "descendants"]:
-                return f"Invalid key '{key}'. Allowed keys are 'ancestors' and 'descendants'."
-            
-            value = constraint[key]
-            if isinstance(value, dict):
-                continue
-            elif isinstance(value, list):
-                for item in value:
-                    if not isinstance(item, dict):
-                        return f"The value for '{key}' must be represented as a JSON object or as a list of objects"
-            else:
-                return f"The value for '{key}' must be a JSON object or a list of JSON objects."
-    return True
-
-
 """
 Parse the token from Authorization header
 
diff --git a/src/metadata_constraints.py b/src/metadata_constraints.py
index 5300aebe..4d949ca3 100644
--- a/src/metadata_constraints.py
+++ b/src/metadata_constraints.py
@@ -1,4 +1,8 @@
 from deepdiff import DeepDiff
+from flask import abort
+
+def bad_request_error(err_msg):
+    abort(400, description = err_msg)
 
 def build_constraint(ancestor: dict, descendants: list[dict]) -> dict:
     return {
@@ -151,9 +155,37 @@ def validate_exclusions(entry, constraint, key) -> bool:
             return True
     else:
         return False
+    
+    
+"""
+Validates the incoming json for the endpoint /constraints. 
+Returns true if the json matches the required format. If 
+invalid, returns a string explaining why.
+"""
+def constraints_json_is_valid(entry):
+    if not isinstance(entry, dict):
+        return "Each constraint in the list must be a JSON object."
+
+    for key in entry:
+        if key not in ["ancestors", "descendants"]:
+            return f"Invalid key '{key}'. Allowed keys are 'ancestors' and 'descendants'."
+        
+        value = entry[key]
+        if isinstance(value, dict):
+            continue
+        elif isinstance(value, list):
+            for item in value:
+                if not isinstance(item, dict):
+                    return f"The value for '{key}' must be represented as a JSON object or as a list of objects"
+        else:
+            return f"The value for '{key}' must be a JSON object or a list of JSON objects."
+    return True
 
 
 def get_constraints(entry, key1, key2, is_match=False) -> dict:
+    is_valid = constraints_json_is_valid(entry)
+    if is_valid is not True:
+        bad_request_error(is_valid)
     entry_key1 = get_constraint_unit(entry.get(key1))
     msg = f"Missing `{key1}` in request. Use orders=ancestors|descendants request param to specify. Default: ancestors"
     result = {'code': 400, 'name': "Bad Request"} if is_match else {'code': 200, 'name': 'OK', 'description': 'Nothing to validate.'}