diff --git a/bindings/python/Cargo.toml b/bindings/python/Cargo.toml
index 3b1b1bbf..b494e408 100644
--- a/bindings/python/Cargo.toml
+++ b/bindings/python/Cargo.toml
@@ -17,7 +17,6 @@ env_logger = "0.11"
 pyo3 = { version = "0.21" }
 numpy = "0.21"
 ndarray = "0.15"
-onig = { version = "6.4", default-features = false }
 itertools = "0.12"
 
 [dependencies.tokenizers]
diff --git a/bindings/python/src/utils/regex.rs b/bindings/python/src/utils/regex.rs
index 82893ca7..16f70682 100644
--- a/bindings/python/src/utils/regex.rs
+++ b/bindings/python/src/utils/regex.rs
@@ -1,11 +1,11 @@
-use onig::Regex;
 use pyo3::exceptions;
 use pyo3::prelude::*;
+use tk::utils::SysRegex;
 
 /// Instantiate a new Regex with the given pattern
 #[pyclass(module = "tokenizers", name = "Regex")]
 pub struct PyRegex {
-    pub inner: Regex,
+    pub inner: SysRegex,
     pub pattern: String,
 }
 
@@ -15,8 +15,8 @@ impl PyRegex {
     #[pyo3(text_signature = "(self, pattern)")]
     fn new(s: &str) -> PyResult<Self> {
         Ok(Self {
-            inner: Regex::new(s)
-                .map_err(|e| exceptions::PyException::new_err(e.description().to_owned()))?,
+            inner: SysRegex::new(s)
+                .map_err(|e| exceptions::PyException::new_err(e.to_string().to_owned()))?,
             pattern: s.to_owned(),
         })
     }
diff --git a/tokenizers/src/utils/fancy.rs b/tokenizers/src/utils/fancy.rs
index 9d94fd7a..9d44bc74 100644
--- a/tokenizers/src/utils/fancy.rs
+++ b/tokenizers/src/utils/fancy.rs
@@ -1,3 +1,5 @@
+use crate::tokenizer::pattern::Pattern;
+use crate::Offsets;
 use fancy_regex::Regex;
 use std::error::Error;
 
@@ -31,3 +33,31 @@ impl<'r, 't> Iterator for Matches<'r, 't> {
         }
     }
 }
+
+impl Pattern for &Regex {
+    fn find_matches(
+        &self,
+        inside: &str,
+    ) -> Result<Vec<(Offsets, bool)>, Box<dyn Error + Send + Sync + 'static>> {
+        if inside.is_empty() {
+            return Ok(vec![((0, 0), false)]);
+        }
+
+        let mut prev = 0;
+        let mut splits = Vec::with_capacity(inside.len());
+        for match_ in self.find_iter(inside) {
+            let match_ = match_?;
+            let start = match_.start();
+            let end = match_.end();
+            if prev != start {
+                splits.push(((prev, start), false));
+            }
+            splits.push(((start, end), true));
+            prev = end;
+        }
+        if prev != inside.len() {
+            splits.push(((prev, inside.len()), false))
+        }
+        Ok(splits)
+    }
+}