diff --git a/client_encryption/api_encryption.py b/client_encryption/api_encryption.py
index 0c24db4..470900b 100644
--- a/client_encryption/api_encryption.py
+++ b/client_encryption/api_encryption.py
@@ -34,8 +34,10 @@ def field_encryption_call_api(self, func):
 
         @wraps(func)
         def call_api_function(*args, **kwargs):
-            check_type = inspect.signature(func.__self__.call_api).parameters.get("_check_type") is None
-            if check_type:
+            original_parameters = inspect.signature(func.__self__.call_api).parameters 
+            check_type_is_none = original_parameters.get("_check_type") is None
+            preload_content_is_not_none = original_parameters.get("_preload_content") is not None
+            if check_type_is_none and preload_content_is_not_none:
                 kwargs["_preload_content"] = False  # version 4.3.1
             return func(*args, **kwargs)
 
@@ -75,10 +77,17 @@ def _encrypt_payload(self, headers, body):
 
         conf = self._encryption_conf
 
-        if type(conf) is FieldLevelEncryptionConfig:
-            return self.encrypt_field_level_payload(headers, conf, body)
-        else:
-            return self.encrypt_jwe_payload(conf, body)
+        encrypted_payload = self.encrypt_field_level_payload(headers, conf, body) if type(
+            conf) is FieldLevelEncryptionConfig else self.encrypt_jwe_payload(conf, body)
+
+        # convert the encrypted_payload to the same data type as the input body
+        if isinstance(body, str):
+            return json.dumps(encrypted_payload)
+
+        if isinstance(body, bytes):
+            return json.dumps(encrypted_payload).encode("utf-8")
+
+        return encrypted_payload
 
     def _decrypt_payload(self, headers, body):
         """Encryption enforcement based on configuration - decrypt using session key params from header or body"""
diff --git a/client_encryption/version.py b/client_encryption/version.py
index 29c1469..bed4083 100644
--- a/client_encryption/version.py
+++ b/client_encryption/version.py
@@ -1,3 +1,3 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
-__version__ = "1.7.0"
+__version__ = "1.8.0"
diff --git a/tests/test_api_encryption.py b/tests/test_api_encryption.py
index 8860792..d786691 100644
--- a/tests/test_api_encryption.py
+++ b/tests/test_api_encryption.py
@@ -39,6 +39,28 @@ def test_ApiEncryption_with_config_as_dict(self, FieldLevelEncryptionConfig):
     def test_ApiEncryption_fail_with_config_as_string(self):
         self.assertRaises(FileNotFoundError, to_test.ApiEncryption, "this is not accepted")
 
+    def test_encrypt_payload_returns_same_data_type_as_input(self):
+        api_encryption = to_test.ApiEncryption(self._json_config)
+
+        test_headers = {"Content-Type": "application/json"}
+
+        body = {
+            "data": {
+                "secret1": "test",
+                "secret2": "secret"
+            },
+            "encryptedData": {}
+        }
+
+        encrypted = api_encryption._encrypt_payload(body=body, headers=test_headers)
+        self.assertIsInstance(encrypted, dict)
+
+        encrypted = api_encryption._encrypt_payload(body=json.dumps(body), headers=test_headers)
+        self.assertIsInstance(encrypted, str)
+
+        encrypted = api_encryption._encrypt_payload(body=json.dumps(body).encode("utf-8"), headers=test_headers)
+        self.assertIsInstance(encrypted, bytes)
+
     def test_encrypt_payload_with_params_in_body(self):
         api_encryption = to_test.ApiEncryption(self._json_config)