diff --git a/msa_sdk/msa_api.py b/msa_sdk/msa_api.py
index 7101542..1b92c0d 100644
--- a/msa_sdk/msa_api.py
+++ b/msa_sdk/msa_api.py
@@ -4,15 +4,17 @@
 import os
 import random
 import sys
+from typing import Optional
 
 import requests
+from requests import Response
 
 from msa_sdk import constants
 from msa_sdk import context
 
 logger = logging.getLogger("msa-sdk")
 
-def host_port():
+def host_port() -> tuple[str, str]:
     """
     Hostname and port of the API.
 
@@ -37,11 +39,11 @@ class MSA_API():  # pylint: disable=invalid-name
 
     def __init__(self):
         """Initialize."""
-        self.url = 'http://{}:{}/ubi-api-rest'.format(*host_port())
-        self.path = ""
-        self.response = None
-        self.log_response = True
-        self._content = ""
+        self.url: str = 'http://{}:{}/ubi-api-rest'.format(*host_port())
+        self.path: str = ""
+        self.response: Optional[Response] = None
+        self.log_response: bool = True
+        self._content: str = ""
         self.action = self.__class__
 
     @classmethod
@@ -224,7 +226,7 @@ def check_response(self):
 
 
         """
-        if not self.response.ok:
+        if self.response is not None and not self.response.ok:
             json_response = self.response.json()
             self._content = self.process_content(self.FAILED, self.action,
                                                  json_response['message'])
@@ -329,7 +331,7 @@ def _call_delete(self) -> None:
         self._content = self.response.text
         self.check_response()
 
-    def add_trace_headers(self, headers):
+    def add_trace_headers(self, headers: dict[str, str]):
         """Add W3C trace headers."""
         if 'TRACEID' not in context:
             t, s = self.create_trace_id()
diff --git a/msa_sdk/profile.py b/msa_sdk/profile.py
index fcd357f..11d42e1 100644
--- a/msa_sdk/profile.py
+++ b/msa_sdk/profile.py
@@ -4,8 +4,7 @@
 The Profile class inherits from MSA_API and provides methods to check the existence
 of profiles and perform other profile-related operations.
 """
-
-import json
+from urllib.parse import urlencode
 
 from msa_sdk.msa_api import MSA_API
 
@@ -41,7 +40,13 @@ def exist(self, reference) -> bool:
             True if the profile exists, False otherwise.
         """
         self.action = 'Check Profile exist by reference'
-        self.path = '{}/v1/exist/{}'.format(self.api_path, reference)
-        self._call_post()
-        result = json.loads(self.content)
-        return result.get('exist', False)
\ No newline at end of file
+        url_encoded = urlencode({'extRef': reference})
+        self.path = '{}/ref?{}'.format(self.api_path, url_encoded)
+        self._call_get()
+        if self.response is None:
+            raise Exception("No response received from the server.")
+        if self.response.status_code == 404:
+            return False
+        if self.response.status_code == 200:
+            return True
+        raise Exception("Unexpected response code: {}".format(self.response.status_code))
\ No newline at end of file
diff --git a/tests/test_profie.py b/tests/test_profie.py
deleted file mode 100644
index ad0022f..0000000
--- a/tests/test_profie.py
+++ /dev/null
@@ -1,20 +0,0 @@
-"""
-Test Profile
-"""
-
-from unittest.mock import patch
-
-from util import profile_fixture
-
-
-def test_exist(profile_fixture):
-    """
-    Test exist profile by reference
-    """
-    with patch('msa_sdk.msa_api.MSA_API._call_post') as mock_call_post:
-        profile = profile_fixture
-        reference = "test1"
-        profile.exist(reference)
-
-        assert profile.path == "/profile/v1/exist/test1"
-        mock_call_post.assert_called_once()
\ No newline at end of file
diff --git a/tests/test_profile_exist.py b/tests/test_profile_exist.py
new file mode 100644
index 0000000..d83adc5
--- /dev/null
+++ b/tests/test_profile_exist.py
@@ -0,0 +1,45 @@
+import pytest
+
+from msa_sdk.profile import Profile
+
+
+class DummyResponse:
+    def __init__(self, status_code):
+        self.status_code = status_code
+
+class DummyProfile(Profile):
+    def _call_get(self):
+        # This will be set in the test
+        pass
+
+def test_exist_returns_true(monkeypatch):
+    profile = DummyProfile()
+    def fake_call_get():
+        profile.response = DummyResponse(200)
+    profile._call_get = fake_call_get
+    assert profile.exist('ref1') is True
+
+def test_exist_returns_false(monkeypatch):
+    profile = DummyProfile()
+    def fake_call_get():
+        profile.response = DummyResponse(404)
+    profile._call_get = fake_call_get
+    assert profile.exist('ref2') is False
+
+
+def test_exist_raises_no_response(monkeypatch):
+    profile = DummyProfile()
+    def fake_call_get():
+        profile.response = None
+    profile._call_get = fake_call_get
+    with pytest.raises(Exception, match="No response received from the server."):
+        profile.exist('ref3')
+
+
+def test_exist_raises_unexpected_code(monkeypatch):
+    profile = DummyProfile()
+    def fake_call_get():
+        profile.response = DummyResponse(500)
+    profile._call_get = fake_call_get
+    with pytest.raises(Exception, match="Unexpected response code: 500"):
+        profile.exist('ref4')