diff --git a/glassure/calc.py b/glassure/calc.py
index 387c3dc..d6536b5 100644
--- a/glassure/calc.py
+++ b/glassure/calc.py
@@ -26,6 +26,13 @@
     extrapolate_to_zero_spline,
 )
 
+# only export functions inside of this file
+__all__ = [
+    "create_calculate_pdf_configs",
+    "calculate_pdf",
+    "validate_input",
+]
+
 
 def create_calculate_pdf_configs(
     data: Pattern,