diff --git a/nhonga_api/client.py b/nhonga_api/client.py
index 710d526..29a00fe 100644
--- a/nhonga_api/client.py
+++ b/nhonga_api/client.py
@@ -3,6 +3,7 @@
 """
 
 import requests
+import hmac
 from typing import Optional, Callable, Union, Awaitable
 from .types import (
     NhongaConfig,
@@ -29,7 +30,7 @@ def __init__(self, config: NhongaConfig):
         """
         self.api_key = config["api_key"]
         self.secret_key = config.get("secret_key")
-        self.base_url = config.get("base_url", "https://vendorapay.com/api")
+        self.base_url = config.get("base_url", "https://nhonga.net/api")
         
         self.session = requests.Session()
         self.session.headers.update({
@@ -149,7 +150,7 @@ def validate_webhook(self, payload: WebhookPayload, received_secret_key: str) ->
         """
         if not self.secret_key:
             raise NhongaError("Secret key not configured for webhook validation")
-        return self.secret_key == received_secret_key
+        return hmac.compare_digest(self.secret_key, received_secret_key)
     
     def process_webhook(
         self, 
diff --git a/nhonga_api/examples.py b/nhonga_api/examples.py
index 3999988..3bf54ae 100644
--- a/nhonga_api/examples.py
+++ b/nhonga_api/examples.py
@@ -228,8 +228,9 @@ def processar_pagamento(webhook_data: WebhookPayload):
 def exemplo_context_manager():
     """Exemplo usando context manager"""
     
+    # ⚠️ IMPORTANTE: Substitua pelas suas credenciais reais ou use variáveis de ambiente
     with NhongaAPI({
-        "api_key": "SUA_CHAVE_API",
+        "api_key": "SUA_CHAVE_API",  # Substitua pela sua chave API real
         "secret_key": "SUA_CHAVE_SECRETA"
     }) as nhonga:
         
diff --git a/nhonga_api/types.py b/nhonga_api/types.py
index 9c4c8c3..12a2c47 100644
--- a/nhonga_api/types.py
+++ b/nhonga_api/types.py
@@ -45,7 +45,7 @@ class CreatePaymentRequest(TypedDict, total=False):
     callbackUrl: Optional[str]
     returnUrl: Optional[str]
     currency: Optional[Currency]
-    enviroment: Optional[Environment]
+    environment: Optional[Environment]
 
 
 class CreatePaymentResponse(TypedDict):