diff --git a/README.md b/README.md
index 3f119c6..1cc1ac2 100644
--- a/README.md
+++ b/README.md
@@ -9,10 +9,20 @@ Python lib for WEG solar energy platform, [SunWEG.net](https://sunweg.net/)
 
 ## Usage
 
+### Retrieve token
+You need to use devtools from your browser to retrieve the token. In most of them, you can open devtools by pressing F12.
+Inside the network tab, you need to check the preserve logs and then do a login.
+
+You can find the token in the request header of various XHR requests, for example:
+![Devtools with a request with a token](img/image.png)
+
+It will be available in the X-Auth-Token-Update header.
+
+### Code sample
 ``` python
 from sunweg.api import APIHelper
 
-api = APIHelper('username','password')
+api = APIHelper(token='your token here')
 plants = api.listPlants()
 for plant in plants:
     print(plant)
diff --git a/img/image.png b/img/image.png
new file mode 100644
index 0000000..d4851c1
Binary files /dev/null and b/img/image.png differ
diff --git a/sunweg/api.py b/sunweg/api.py
index 0331188..55a90e2 100644
--- a/sunweg/api.py
+++ b/sunweg/api.py
@@ -83,20 +83,36 @@ class APIHelper:
 
     SERVER_URI = SUNWEG_URL
 
-    def __init__(self, username: str, password: str) -> None:
+    def __init__(
+        self,
+        username: str | None = None,
+        password: str | None = None,
+        token: str | None = None,
+    ) -> None:
         """
         Initialize APIHelper for SunWEG platform.
 
         :param username: username for authentication
         :param password: password for authentication
+        :param token: token for authentication
         :type username: str
         :type password: str
+        :type token: str
         """
-        self._token = None
+        self._token = token
         self._username = username
         self._password = password
         self.session = session()
 
+    def set_token(self, token: str) -> None:
+        """
+        Set token.
+
+        :param token: token for authentication
+        :type token: str
+        """
+        self._token = token
+
     def _set_username(self, username: str) -> None:
         """
         Set username.
@@ -126,6 +142,9 @@ def authenticate(self) -> bool:
         :return: True on authentication success
         :rtype: bool
         """
+        if self._username is None or self._password is None:
+            return False
+
         user_data = json.dumps(
             {"usuario": self._username, "senha": self._password, "rememberMe": True},
             default=lambda o: o.__dict__,
diff --git a/tests/test_api.py b/tests/test_api.py
index d5aca0c..8032f9c 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -97,6 +97,17 @@ def test_error500(self) -> None:
                 api.authenticate()
             assert e_info.value.__str__() == "Request failed: <Response [500]>"
 
+    def test_initialize_token(self) -> None:
+        """Test initialize token."""
+        api = APIHelper(token="token")
+        assert api._token == "token"
+
+    def test_set_token(self) -> None:
+        """Test set token."""
+        api = APIHelper(token="token")
+        api.set_token("new_token")
+        assert api._token == "new_token"
+
     def test_authenticate_success(self) -> None:
         """Test authentication success."""
         with patch(
@@ -106,6 +117,11 @@ def test_authenticate_success(self) -> None:
             api = APIHelper("user@acme.com", "password")
             assert api.authenticate()
 
+    def test_authenticate_fail_empty_credentials(self) -> None:
+        """Test authentication failed."""
+        api = APIHelper(None, None)
+        assert not api.authenticate()
+
     def test_authenticate_failed(self) -> None:
         """Test authentication failed."""
         with patch(