diff --git a/src/lib.rs b/src/lib.rs
index eef7b29cc0a34538da179d9b3b02d630d0839852_c3JjL2xpYi5ycw==..b3355f838c46195e3ac513d7d7726f40ba652800_c3JjL2xpYi5ycw== 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -20,7 +20,7 @@
 use std::os::raw::c_char;
 use std::ptr::NonNull;
 
-const DUMPS_DOC: &str = "dumps(obj, /, default, option)\n--\n\nSerialize Python objects to JSON.\0";
+const DUMPS_DOC: &str = "dumps(obj, /, default=None, option=None)\n--\n\nSerialize Python objects to JSON.\0";
 const LOADS_DOC: &str = "loads(obj, /)\n--\n\nDeserialize JSON to Python objects.\0";
 
 macro_rules! opt {
diff --git a/test/test_api.py b/test/test_api.py
index eef7b29cc0a34538da179d9b3b02d630d0839852_dGVzdC90ZXN0X2FwaS5weQ==..b3355f838c46195e3ac513d7d7726f40ba652800_dGVzdC90ZXN0X2FwaS5weQ== 100644
--- a/test/test_api.py
+++ b/test/test_api.py
@@ -166,5 +166,5 @@
         dumps() valid __text_signature__
         """
         self.assertEqual(
-            str(inspect.signature(orjson.dumps)), "(obj, /, default, option)"
+            str(inspect.signature(orjson.dumps)), "(obj, /, default=None, option=None)"
         )
@@ -170,7 +170,9 @@
         )
+        inspect.signature(orjson.dumps).bind("str")
+        inspect.signature(orjson.dumps).bind("str", default=default, option=1)
 
     def test_loads_signature(self):
         """
         loads() valid __text_signature__
         """
         self.assertEqual(str(inspect.signature(orjson.loads)), "(obj, /)")
@@ -171,9 +173,10 @@
 
     def test_loads_signature(self):
         """
         loads() valid __text_signature__
         """
         self.assertEqual(str(inspect.signature(orjson.loads)), "(obj, /)")
+        inspect.signature(orjson.loads).bind("[]")
 
     def test_bytes_buffer(self):
         """