diff --git a/TodoParser.py b/TodoParser.py
index 6101704..af4dc05 100644
--- a/TodoParser.py
+++ b/TodoParser.py
@@ -24,22 +24,30 @@ class TodoParser(object):
     ISSUE_URL_PATTERN = re.compile(r'(?<=Issue URL:\s).+', re.IGNORECASE)
     ISSUE_NUMBER_PATTERN = re.compile(r'/issues/(\d+)', re.IGNORECASE)
 
-    def __init__(self):
+    def __init__(self, options=dict()):
         # Determine if the issues should be escaped.
         self.should_escape = os.getenv('INPUT_ESCAPE', 'true') == 'true'
-        # Load any custom identifiers, otherwise use the default.
+        # Load any custom identifiers specified by the environment,
+        # falling back to any specified by the constructor argument,
+        # otherwise using the default.
         custom_identifiers = os.getenv('INPUT_IDENTIFIERS')
         self.identifiers = ['TODO']
         self.identifiers_dict = None
         if custom_identifiers:
             try:
                 custom_identifiers_dict = json.loads(custom_identifiers)
+            except json.JSONDecodeError:
+                print('Invalid identifiers dict, ignoring.')
+        else:
+            custom_identifiers_dict = options.get("identifiers", None)
+        if custom_identifiers_dict:
+            try:
                 for identifier_dict in custom_identifiers_dict:
                     if type(identifier_dict['name']) is not str or type(identifier_dict['labels']) is not list:
                         raise TypeError
                 self.identifiers = [identifier['name'] for identifier in custom_identifiers_dict]
                 self.identifiers_dict = custom_identifiers_dict
-            except (json.JSONDecodeError, KeyError, TypeError):
+            except (KeyError, TypeError):
                 print('Invalid identifiers dict, ignoring.')
 
         self.languages_dict = None