diff --git a/src/dolibarr_mcp/simple_client.py b/src/dolibarr_mcp/simple_client.py
new file mode 100644
index 0000000..80fb13c
--- /dev/null
+++ b/src/dolibarr_mcp/simple_client.py
@@ -0,0 +1,318 @@
+"""Ultra-simple Dolibarr API client - Windows compatible, zero compiled extensions."""
+
+import json
+import logging
+import os
+import sys
+from typing import Any, Dict, List, Optional, Union
+
+# Only use standard library + requests (pure Python)
+import requests
+from requests.adapters import HTTPAdapter
+from urllib3.util.retry import Retry
+
+# Minimal config handling without pydantic
+class SimpleConfig:
+    """Simple configuration without pydantic - no compiled extensions."""
+    
+    def __init__(self):
+        # Load .env manually
+        self.load_env()
+        
+        self.dolibarr_url = os.getenv("DOLIBARR_URL", "")
+        self.api_key = os.getenv("DOLIBARR_API_KEY", "")
+        self.log_level = os.getenv("LOG_LEVEL", "INFO")
+        
+        # Validate and fix URL
+        if not self.dolibarr_url or "your-dolibarr-instance" in self.dolibarr_url:
+            print("⚠️  DOLIBARR_URL not configured in .env file", file=sys.stderr)
+            self.dolibarr_url = "https://your-dolibarr-instance.com/api/index.php"
+        
+        if not self.api_key or "your_dolibarr_api_key" in self.api_key:
+            print("⚠️  DOLIBARR_API_KEY not configured in .env file", file=sys.stderr)
+            self.api_key = "placeholder_api_key"
+        
+        # Ensure URL format
+        if self.dolibarr_url and not self.dolibarr_url.endswith('/api/index.php'):
+            if '/api' not in self.dolibarr_url:
+                self.dolibarr_url = self.dolibarr_url.rstrip('/') + '/api/index.php'
+            elif not self.dolibarr_url.endswith('/index.php'):
+                self.dolibarr_url = self.dolibarr_url.rstrip('/') + '/index.php'
+    
+    def load_env(self):
+        """Load .env file manually - no python-dotenv needed."""
+        env_file = '.env'
+        if os.path.exists(env_file):
+            with open(env_file, 'r', encoding='utf-8') as f:
+                for line in f:
+                    line = line.strip()
+                    if line and not line.startswith('#') and '=' in line:
+                        key, value = line.split('=', 1)
+                        os.environ[key.strip()] = value.strip()
+
+
+class SimpleDolibarrAPIError(Exception):
+    """Simple API error exception."""
+    def __init__(self, message: str, status_code: Optional[int] = None):
+        self.message = message
+        self.status_code = status_code
+        super().__init__(self.message)
+
+
+class SimpleDolibarrClient:
+    """Ultra-simple Dolibarr client using only requests - no aiohttp, no compiled extensions."""
+    
+    def __init__(self, config: SimpleConfig):
+        self.config = config
+        self.base_url = config.dolibarr_url.rstrip('/')
+        self.api_key = config.api_key
+        
+        # Create requests session with retries
+        self.session = requests.Session()
+        
+        # Add retry strategy
+        retry_strategy = Retry(
+            total=3,
+            backoff_factor=1,
+            status_forcelist=[429, 500, 502, 503, 504],
+        )
+        
+        adapter = HTTPAdapter(max_retries=retry_strategy)
+        self.session.mount("http://", adapter)
+        self.session.mount("https://", adapter)
+        
+        # Set headers
+        self.session.headers.update({
+            "DOLAPIKEY": self.api_key,
+            "Content-Type": "application/json",
+            "Accept": "application/json",
+            "User-Agent": "Dolibarr-MCP-Client/1.0"
+        })
+        
+        self.logger = logging.getLogger(__name__)
+    
+    def _build_url(self, endpoint: str) -> str:
+        """Build full API URL."""
+        endpoint = endpoint.lstrip('/')
+        
+        # Special handling for status endpoint
+        if endpoint == "status":
+            base = self.base_url.replace('/index.php', '')
+            return f"{base}/status"
+        
+        return f"{self.base_url}/{endpoint}"
+    
+    def _make_request(
+        self, 
+        method: str, 
+        endpoint: str, 
+        params: Optional[Dict] = None,
+        data: Optional[Dict] = None
+    ) -> Dict[str, Any]:
+        """Make HTTP request to Dolibarr API."""
+        url = self._build_url(endpoint)
+        
+        try:
+            self.logger.debug(f"Making {method} request to {url}")
+            
+            kwargs = {
+                "params": params or {},
+                "timeout": 30
+            }
+            
+            if data and method.upper() in ["POST", "PUT"]:
+                kwargs["json"] = data
+            
+            response = self.session.request(method, url, **kwargs)
+            
+            # Log response for debugging
+            self.logger.debug(f"Response status: {response.status_code}")
+            
+            # Handle error responses
+            if response.status_code >= 400:
+                try:
+                    error_data = response.json()
+                    if isinstance(error_data, dict) and "error" in error_data:
+                        error_msg = str(error_data["error"])
+                    else:
+                        error_msg = f"HTTP {response.status_code}: {response.reason}"
+                except:
+                    error_msg = f"HTTP {response.status_code}: {response.reason}"
+                
+                raise SimpleDolibarrAPIError(error_msg, response.status_code)
+            
+            # Try to parse JSON response
+            try:
+                return response.json()
+            except:
+                # If not JSON, return as text
+                return {"raw_response": response.text}
+        
+        except requests.RequestException as e:
+            # For status endpoint, try alternative
+            if endpoint == "status":
+                try:
+                    alt_url = f"{self.base_url.replace('/api/index.php', '')}/setup/modules"
+                    alt_response = self.session.get(alt_url, timeout=10)
+                    if alt_response.status_code == 200:
+                        return {
+                            "success": 1,
+                            "dolibarr_version": "API Available",
+                            "api_version": "1.0"
+                        }
+                except:
+                    pass
+            
+            raise SimpleDolibarrAPIError(f"HTTP request failed: {str(e)}")
+        except Exception as e:
+            raise SimpleDolibarrAPIError(f"Unexpected error: {str(e)}")
+    
+    # ============================================================================
+    # SYSTEM ENDPOINTS
+    # ============================================================================
+    
+    def get_status(self) -> Dict[str, Any]:
+        """Get API status and version information."""
+        try:
+            return self._make_request("GET", "status")
+        except SimpleDolibarrAPIError:
+            # Try alternatives
+            try:
+                result = self._make_request("GET", "users?limit=1")
+                if result is not None:
+                    return {
+                        "success": 1,
+                        "dolibarr_version": "API Working",
+                        "api_version": "1.0"
+                    }
+            except:
+                pass
+            
+            raise SimpleDolibarrAPIError("Cannot connect to Dolibarr API. Please check your configuration.")
+    
+    # ============================================================================
+    # USER MANAGEMENT
+    # ============================================================================
+    
+    def get_users(self, limit: int = 100, page: int = 1) -> List[Dict[str, Any]]:
+        """Get list of users."""
+        params = {"limit": limit}
+        if page > 1:
+            params["page"] = page
+        
+        result = self._make_request("GET", "users", params=params)
+        return result if isinstance(result, list) else []
+    
+    def get_user_by_id(self, user_id: int) -> Dict[str, Any]:
+        """Get specific user by ID."""
+        return self._make_request("GET", f"users/{user_id}")
+    
+    def create_user(self, **kwargs) -> Dict[str, Any]:
+        """Create a new user."""
+        return self._make_request("POST", "users", data=kwargs)
+    
+    def update_user(self, user_id: int, **kwargs) -> Dict[str, Any]:
+        """Update an existing user."""
+        return self._make_request("PUT", f"users/{user_id}", data=kwargs)
+    
+    def delete_user(self, user_id: int) -> Dict[str, Any]:
+        """Delete a user."""
+        return self._make_request("DELETE", f"users/{user_id}")
+    
+    # ============================================================================
+    # CUSTOMER MANAGEMENT
+    # ============================================================================
+    
+    def get_customers(self, limit: int = 100, page: int = 1) -> List[Dict[str, Any]]:
+        """Get list of customers/third parties."""
+        params = {"limit": limit}
+        if page > 1:
+            params["page"] = page
+        
+        result = self._make_request("GET", "thirdparties", params=params)
+        return result if isinstance(result, list) else []
+    
+    def get_customer_by_id(self, customer_id: int) -> Dict[str, Any]:
+        """Get specific customer by ID."""
+        return self._make_request("GET", f"thirdparties/{customer_id}")
+    
+    def create_customer(self, name: str, **kwargs) -> Dict[str, Any]:
+        """Create a new customer."""
+        data = {
+            "name": name,
+            "status": kwargs.get("status", 1),
+            "client": 1 if kwargs.get("type", 1) in [1, 3] else 0,
+            "fournisseur": 1 if kwargs.get("type", 1) in [2, 3] else 0,
+            "country_id": kwargs.get("country_id", 1),
+        }
+        
+        # Add optional fields
+        for field in ["email", "phone", "address", "town", "zip"]:
+            if field in kwargs:
+                data[field] = kwargs[field]
+        
+        return self._make_request("POST", "thirdparties", data=data)
+    
+    def update_customer(self, customer_id: int, **kwargs) -> Dict[str, Any]:
+        """Update an existing customer."""
+        return self._make_request("PUT", f"thirdparties/{customer_id}", data=kwargs)
+    
+    def delete_customer(self, customer_id: int) -> Dict[str, Any]:
+        """Delete a customer."""
+        return self._make_request("DELETE", f"thirdparties/{customer_id}")
+    
+    # ============================================================================
+    # PRODUCT MANAGEMENT
+    # ============================================================================
+    
+    def get_products(self, limit: int = 100) -> List[Dict[str, Any]]:
+        """Get list of products."""
+        params = {"limit": limit}
+        result = self._make_request("GET", "products", params=params)
+        return result if isinstance(result, list) else []
+    
+    def get_product_by_id(self, product_id: int) -> Dict[str, Any]:
+        """Get specific product by ID."""
+        return self._make_request("GET", f"products/{product_id}")
+    
+    def create_product(self, label: str, price: float, **kwargs) -> Dict[str, Any]:
+        """Create a new product."""
+        import time
+        
+        # Generate ref if not provided
+        ref = kwargs.get("ref", f"PROD-{int(time.time())}")
+        
+        data = {
+            "ref": ref,
+            "label": label,
+            "price": price,
+            "price_ttc": price,
+        }
+        
+        # Add optional fields
+        for field in ["description", "stock"]:
+            if field in kwargs:
+                data[field] = kwargs[field]
+        
+        return self._make_request("POST", "products", data=data)
+    
+    def update_product(self, product_id: int, **kwargs) -> Dict[str, Any]:
+        """Update an existing product."""
+        return self._make_request("PUT", f"products/{product_id}", data=kwargs)
+    
+    def delete_product(self, product_id: int) -> Dict[str, Any]:
+        """Delete a product."""
+        return self._make_request("DELETE", f"products/{product_id}")
+    
+    # ============================================================================
+    # RAW API CALL
+    # ============================================================================
+    
+    def raw_api(self, method: str, endpoint: str, params: Optional[Dict] = None, data: Optional[Dict] = None) -> Dict[str, Any]:
+        """Make raw API call to any Dolibarr endpoint."""
+        return self._make_request(method, endpoint, params=params, data=data)
+    
+    def close(self):
+        """Close the session."""
+        if self.session:
+            self.session.close()