diff --git a/python/outlines_core/fsm/guide.py b/python/outlines_core/fsm/guide.py
index 18b4523c..bb7561a7 100644
--- a/python/outlines_core/fsm/guide.py
+++ b/python/outlines_core/fsm/guide.py
@@ -7,9 +7,10 @@
     create_fsm_index_tokenizer,
     make_byte_level_fsm,
     make_deterministic_fsm,
+    reduced_vocabulary,
 )
 
-from .outlines_core_rs import Index
+from .outlines_core_rs import Index, Vocabulary
 
 
 @dataclass(frozen=True)
@@ -137,8 +138,17 @@ def create_states_mapping(
     final_states:
         A set of final states in the FSM.
     """
-    regex_fsm = regex_parser(regex_string).to_fsm()
-    return create_states_mapping_from_fsm(regex_fsm, tokenizer, frozen_tokens)
+    # regex_fsm = regex_parser(regex_string).to_fsm()
+    # return create_states_mapping_from_fsm(regex_fsm, tokenizer, frozen_tokens)
+
+    # inlining logic of create_fsm_index_tokenizer
+    tokens_to_token_ids, empty_token_ids = reduced_vocabulary(tokenizer)
+    vocabulary = Vocabulary.from_dict_with_eos_token_id(
+        tokens_to_token_ids, tokenizer.eos_token_id
+    )
+    index = Index.from_regex(regex_string, vocabulary)
+
+    return index, empty_token_ids, set(index.final_states())
 
 
 def create_states_mapping_from_fsm(
diff --git a/python/outlines_core/fsm/outlines_core_rs.pyi b/python/outlines_core/fsm/outlines_core_rs.pyi
index 2bd6c82b..e43a595f 100644
--- a/python/outlines_core/fsm/outlines_core_rs.pyi
+++ b/python/outlines_core/fsm/outlines_core_rs.pyi
@@ -76,6 +76,14 @@ class Vocabulary:
         Creates a vocabulary from a dictionary of tokens to token IDs.
         """
         ...
+    @staticmethod
+    def from_dict_with_eos_token_id(
+        map: Dict[str, List[int]], eos_token_id: int
+    ) -> "Vocabulary":
+        """
+        Creates a vocabulary from a dictionary of tokens to token IDs and eos token id.
+        """
+        ...
     def __repr__(self) -> str:
         """
         Gets the debug string representation of the vocabulary.
@@ -88,6 +96,12 @@ class Vocabulary:
         ...
 
 class Index:
+    @staticmethod
+    def from_regex(regex: str, vocabulary: "Vocabulary") -> "Index":
+        """
+        Creates an index from a regex and vocabulary.
+        """
+        ...
     def get_allowed_tokens(self, state: int) -> Optional[List[int]]:
         """Returns allowed tokens in this state."""
         ...
@@ -97,6 +111,9 @@ class Index:
     def is_final_state(self, state: int) -> bool:
         """Determines whether the current state is a final state."""
         ...
+    def final_states(self) -> List[int]:
+        """Get all final states."""
+        ...
     def get_index_dict(self) -> Dict[int, Dict[int, int]]:
         """Returns the Index as a Python Dict object."""
         ...
diff --git a/src/python_bindings/mod.rs b/src/python_bindings/mod.rs
index 84b8746d..944ca150 100644
--- a/src/python_bindings/mod.rs
+++ b/src/python_bindings/mod.rs
@@ -93,6 +93,15 @@ impl PyIndex {
         })
     }
 
+    #[staticmethod]
+    fn from_regex(py: Python<'_>, regex: &str, vocabulary: &PyVocabulary) -> PyResult<Self> {
+        py.allow_threads(|| {
+            Index::from_regex(regex, &vocabulary.0)
+                .map(PyIndex)
+                .map_err(Into::into)
+        })
+    }
+
     fn __reduce__(&self) -> PyResult<(PyObject, (Vec<u8>,))> {
         Python::with_gil(|py| {
             let cls = PyModule::import_bound(py, "outlines_core.fsm.outlines_core_rs")?
@@ -126,6 +135,10 @@ impl PyIndex {
         self.0.is_final(state)
     }
 
+    fn final_states(&self) -> FxHashSet<State> {
+        self.0.final_states().clone()
+    }
+
     fn get_transitions(&self) -> FxHashMap<u32, FxHashMap<u32, u32>> {
         self.0.transitions().clone()
     }
@@ -291,6 +304,15 @@ impl PyVocabulary {
         PyVocabulary(Vocabulary::from(map))
     }
 
+    #[staticmethod]
+    fn from_dict_with_eos_token_id(
+        map: FxHashMap<Token, Vec<TokenId>>,
+        eos_token_id: TokenId,
+    ) -> PyVocabulary {
+        let v = Vocabulary::from(map).with_eos_token_id(Some(eos_token_id));
+        PyVocabulary(v)
+    }
+
     fn __repr__(&self) -> String {
         format!("{:#?}", self.0)
     }