diff --git a/aixplain/modules/model/__init__.py b/aixplain/modules/model/__init__.py
index 765960d4..126df503 100644
--- a/aixplain/modules/model/__init__.py
+++ b/aixplain/modules/model/__init__.py
@@ -188,7 +188,7 @@ def run(
         data: Union[Text, Dict],
         name: Text = "model_process",
         timeout: float = 300,
-        parameters: Optional[Dict] = {},
+        parameters: Optional[Dict] = None,
         wait_time: float = 0.5,
     ) -> Dict:
         """Runs a model call.
@@ -197,7 +197,7 @@ def run(
             data (Union[Text, Dict]): link to the input data
             name (Text, optional): ID given to a call. Defaults to "model_process".
             timeout (float, optional): total polling time. Defaults to 300.
-            parameters (Dict, optional): optional parameters to the model. Defaults to "{}".
+            parameters (Dict, optional): optional parameters to the model. Defaults to None.
             wait_time (float, optional): wait time in seconds between polling calls. Defaults to 0.5.
 
         Returns:
@@ -220,13 +220,13 @@ def run(
                 response = {"status": "FAILED", "error": msg, "elapsed_time": end - start}
         return response
 
-    def run_async(self, data: Union[Text, Dict], name: Text = "model_process", parameters: Optional[Dict] = {}) -> Dict:
+    def run_async(self, data: Union[Text, Dict], name: Text = "model_process", parameters: Optional[Dict] = None) -> Dict:
         """Runs asynchronously a model call.
 
         Args:
             data (Union[Text, Dict]): link to the input data
             name (Text, optional): ID given to a call. Defaults to "model_process".
-            parameters (Dict, optional): optional parameters to the model. Defaults to "{}".
+            parameters (Dict, optional): optional parameters to the model. Defaults to None.
 
         Returns:
             dict: polling URL in response
diff --git a/aixplain/modules/model/llm_model.py b/aixplain/modules/model/llm_model.py
index f48a3068..f0b4cef6 100644
--- a/aixplain/modules/model/llm_model.py
+++ b/aixplain/modules/model/llm_model.py
@@ -102,7 +102,7 @@ def run(
         top_p: float = 1.0,
         name: Text = "model_process",
         timeout: float = 300,
-        parameters: Optional[Dict] = {},
+        parameters: Optional[Dict] = None,
         wait_time: float = 0.5,
     ) -> Dict:
         """Synchronously running a Large Language Model (LLM) model.
@@ -117,21 +117,23 @@ def run(
             top_p (float, optional): Top P. Defaults to 1.0.
             name (Text, optional): ID given to a call. Defaults to "model_process".
             timeout (float, optional): total polling time. Defaults to 300.
-            parameters (Dict, optional): optional parameters to the model. Defaults to "{}".
+            parameters (Dict, optional): optional parameters to the model. Defaults to None.
             wait_time (float, optional): wait time in seconds between polling calls. Defaults to 0.5.
 
         Returns:
             Dict: parsed output from model
         """
         start = time.time()
+        if parameters is None:
+            parameters = {}
         parameters.update(
             {
-                "context": parameters["context"] if "context" in parameters else context,
-                "prompt": parameters["prompt"] if "prompt" in parameters else prompt,
-                "history": parameters["history"] if "history" in parameters else history,
-                "temperature": parameters["temperature"] if "temperature" in parameters else temperature,
-                "max_tokens": parameters["max_tokens"] if "max_tokens" in parameters else max_tokens,
-                "top_p": parameters["top_p"] if "top_p" in parameters else top_p,
+                "context": parameters.get("context", context),
+                "prompt": parameters.get("prompt", prompt),
+                "history": parameters.get("history", history),
+                "temperature": parameters.get("temperature", temperature),
+                "max_tokens": parameters.get("max_tokens", max_tokens),
+                "top_p": parameters.get("top_p", top_p),
             }
         )
         payload = build_payload(data=data, parameters=parameters)
@@ -160,7 +162,7 @@ def run_async(
         max_tokens: int = 128,
         top_p: float = 1.0,
         name: Text = "model_process",
-        parameters: Optional[Dict] = {},
+        parameters: Optional[Dict] = None,
     ) -> Dict:
         """Runs asynchronously a model call.
 
@@ -173,21 +175,23 @@ def run_async(
             max_tokens (int, optional): Maximum Generation Tokens. Defaults to 128.
             top_p (float, optional): Top P. Defaults to 1.0.
             name (Text, optional): ID given to a call. Defaults to "model_process".
-            parameters (Dict, optional): optional parameters to the model. Defaults to "{}".
+            parameters (Dict, optional): optional parameters to the model. Defaults to None.
 
         Returns:
             dict: polling URL in response
         """
         url = f"{self.url}/{self.id}"
         logging.debug(f"Model Run Async: Start service for {name} - {url}")
+        if parameters is None:
+            parameters = {}
         parameters.update(
             {
-                "context": parameters["context"] if "context" in parameters else context,
-                "prompt": parameters["prompt"] if "prompt" in parameters else prompt,
-                "history": parameters["history"] if "history" in parameters else history,
-                "temperature": parameters["temperature"] if "temperature" in parameters else temperature,
-                "max_tokens": parameters["max_tokens"] if "max_tokens" in parameters else max_tokens,
-                "top_p": parameters["top_p"] if "top_p" in parameters else top_p,
+                "context": parameters.get("context", context),
+                "prompt": parameters.get("prompt", prompt),
+                "history": parameters.get("history", history),
+                "temperature": parameters.get("temperature", temperature),
+                "max_tokens": parameters.get("max_tokens", max_tokens),
+                "top_p": parameters.get("top_p", top_p),
             }
         )
         payload = build_payload(data=data, parameters=parameters)
diff --git a/aixplain/modules/model/utils.py b/aixplain/modules/model/utils.py
index 2235b35a..13cc1f7c 100644
--- a/aixplain/modules/model/utils.py
+++ b/aixplain/modules/model/utils.py
@@ -3,12 +3,15 @@
 import json
 import logging
 from aixplain.utils.file_utils import _request_with_retry
-from typing import Dict, Text, Union
+from typing import Dict, Text, Union, Optional
 
 
-def build_payload(data: Union[Text, Dict], parameters: Dict = {}):
+def build_payload(data: Union[Text, Dict], parameters: Optional[Dict] = None):
     from aixplain.factories import FileFactory
 
+    if parameters is None:
+        parameters = {}
+
     data = FileFactory.to_link(data)
     if isinstance(data, dict):
         payload = data