diff --git a/pyproject.toml b/pyproject.toml
index b43a84b3..18ec1760 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -39,6 +39,7 @@ dependencies = [
     "pandas>=1.0.0",
     "pyphen>=0.11.0,<0.15.0",
     "ftfy>=6.0.3,<6.1.0",
+    "pydantic<2.0.0",
 ]
 
 requires-python = ">=3.8"