diff --git a/maskbench/maskbench/outlines_engine.py b/maskbench/maskbench/outlines_engine.py
index beb2ea37..e3d9f198 100644
--- a/maskbench/maskbench/outlines_engine.py
+++ b/maskbench/maskbench/outlines_engine.py
@@ -2,6 +2,7 @@
 import json
 from outlines_core import Vocabulary, Guide, Index
 from outlines_core.json_schema import build_regex_from_schema
+from outlines_core.kernels.torch import allocate_token_bitmask, fill_next_token_bitmask
 
 
 class OutlinesEngine(Engine):
@@ -19,6 +20,7 @@ def get_name(self):
 
     def init(self):
         self.vocabulary = Vocabulary.from_pretrained(self.tokenizer.name_or_path)
+        self.mask = allocate_token_bitmask(len(self.vocabulary))
 
     def compile_grammar(self, schema: dict):
         rx = build_regex_from_schema(json.dumps(schema))
@@ -29,10 +31,10 @@ def reset(self):
         self.guide  = Guide(self.index)
 
     def compute_mask(self):
-        self.res = self.guide.get_tokens()
+        fill_next_token_bitmask(self.guide, self.mask)
 
     def commit_token(self, t: int) -> bool:
-        ok = t in self.res
+        ok = True
         if ok:
-            self.guide.advance(t)
+            self.guide.advance(t, False)
         return ok