diff --git a/oura_api_client/api/daily_activity.py b/oura_api_client/api/daily_activity.py
index 3923ddf..c01e17b 100644
--- a/oura_api_client/api/daily_activity.py
+++ b/oura_api_client/api/daily_activity.py
@@ -2,6 +2,7 @@
 from datetime import date
 from oura_api_client.api.base import BaseRouter
 from oura_api_client.models.daily_activity import DailyActivityResponse, DailyActivityModel
+from oura_api_client.utils import build_query_params
 
 
 class DailyActivity(BaseRouter):
@@ -22,16 +23,7 @@ def get_daily_activity_documents(
         Returns:
             DailyActivityResponse: Response containing daily activity data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         response = self.client._make_request(
             "/usercollection/daily_activity", params=params
         )
diff --git a/oura_api_client/api/daily_cardiovascular_age.py b/oura_api_client/api/daily_cardiovascular_age.py
index e238300..f7f360f 100644
--- a/oura_api_client/api/daily_cardiovascular_age.py
+++ b/oura_api_client/api/daily_cardiovascular_age.py
@@ -1,6 +1,7 @@
 from typing import Optional, Union
 from datetime import date
 from oura_api_client.api.base import BaseRouter
+from oura_api_client.utils import build_query_params
 from oura_api_client.models.daily_cardiovascular_age import (
     DailyCardiovascularAgeResponse,
     DailyCardiovascularAgeModel
@@ -26,16 +27,7 @@ def get_daily_cardiovascular_age_documents(
             DailyCardiovascularAgeResponse: Response containing daily
                 cardiovascular age data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         response = self.client._make_request(
             "/usercollection/daily_cardiovascular_age", params=params
         )
diff --git a/oura_api_client/api/daily_readiness.py b/oura_api_client/api/daily_readiness.py
index ab3611c..4494ff8 100644
--- a/oura_api_client/api/daily_readiness.py
+++ b/oura_api_client/api/daily_readiness.py
@@ -1,6 +1,7 @@
 from typing import Optional, Union
 from datetime import date
 from oura_api_client.api.base import BaseRouter
+from oura_api_client.utils import build_query_params
 from oura_api_client.models.daily_readiness import (
     DailyReadinessResponse,
     DailyReadinessModel
@@ -25,16 +26,7 @@ def get_daily_readiness_documents(
         Returns:
             DailyReadinessResponse: Response containing daily readiness data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         response = self.client._make_request(
             "/usercollection/daily_readiness", params=params
         )
diff --git a/oura_api_client/api/daily_resilience.py b/oura_api_client/api/daily_resilience.py
index 284b518..bdeb522 100644
--- a/oura_api_client/api/daily_resilience.py
+++ b/oura_api_client/api/daily_resilience.py
@@ -1,6 +1,7 @@
 from typing import Optional, Union
 from datetime import date
 from oura_api_client.api.base import BaseRouter
+from oura_api_client.utils import build_query_params
 from oura_api_client.models.daily_resilience import (
     DailyResilienceResponse,
     DailyResilienceModel
@@ -25,16 +26,7 @@ def get_daily_resilience_documents(
         Returns:
             DailyResilienceResponse: Response containing daily resilience data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         response = self.client._make_request(
             "/usercollection/daily_resilience", params=params
         )
diff --git a/oura_api_client/api/daily_sleep.py b/oura_api_client/api/daily_sleep.py
index c068c05..ce0c29c 100644
--- a/oura_api_client/api/daily_sleep.py
+++ b/oura_api_client/api/daily_sleep.py
@@ -1,6 +1,7 @@
 from typing import Optional, Union
 from datetime import date
 from oura_api_client.api.base import BaseRouter
+from oura_api_client.utils import build_query_params
 from oura_api_client.models.daily_sleep import (
     DailySleepResponse,
     DailySleepModel
@@ -25,16 +26,7 @@ def get_daily_sleep_documents(
         Returns:
             DailySleepResponse: Response containing daily sleep data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         response = self.client._make_request(
             "/usercollection/daily_sleep", params=params
         )
diff --git a/oura_api_client/api/daily_spo2.py b/oura_api_client/api/daily_spo2.py
index 9479be8..ea7eda1 100644
--- a/oura_api_client/api/daily_spo2.py
+++ b/oura_api_client/api/daily_spo2.py
@@ -1,6 +1,7 @@
 from typing import Optional, Union
 from datetime import date
 from oura_api_client.api.base import BaseRouter
+from oura_api_client.utils import build_query_params
 from oura_api_client.models.daily_spo2 import (
     DailySpO2Response,
     DailySpO2Model
@@ -25,16 +26,7 @@ def get_daily_spo2_documents(  # Renamed method
         Returns:
             DailySpO2Response: Response containing daily SpO2 data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         response = self.client._make_request(
             "/usercollection/daily_spo2", params=params
         )
diff --git a/oura_api_client/api/daily_stress.py b/oura_api_client/api/daily_stress.py
index 5951641..e8157e2 100644
--- a/oura_api_client/api/daily_stress.py
+++ b/oura_api_client/api/daily_stress.py
@@ -1,6 +1,7 @@
 from typing import Optional, Union
 from datetime import date
 from oura_api_client.api.base import BaseRouter
+from oura_api_client.utils import build_query_params
 from oura_api_client.models.daily_stress import (
     DailyStressResponse,
     DailyStressModel
@@ -25,16 +26,7 @@ def get_daily_stress_documents(
         Returns:
             DailyStressResponse: Response containing daily stress data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         response = self.client._make_request(
             "/usercollection/daily_stress", params=params
         )
diff --git a/oura_api_client/api/enhanced_tag.py b/oura_api_client/api/enhanced_tag.py
index a74146e..710eb6a 100644
--- a/oura_api_client/api/enhanced_tag.py
+++ b/oura_api_client/api/enhanced_tag.py
@@ -1,6 +1,7 @@
 from typing import Optional, Union
 from datetime import date  # Using date for start_date and end_date
 from oura_api_client.api.base import BaseRouter
+from oura_api_client.utils import build_query_params
 from oura_api_client.models.enhanced_tag import (
     EnhancedTagResponse,
     EnhancedTagModel
@@ -25,16 +26,7 @@ def get_enhanced_tag_documents(
         Returns:
             EnhancedTagResponse: Response containing enhanced_tag data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         response = self.client._make_request(
             "/usercollection/enhanced_tag", params=params
         )
diff --git a/oura_api_client/api/rest_mode_period.py b/oura_api_client/api/rest_mode_period.py
index e081848..78fd588 100644
--- a/oura_api_client/api/rest_mode_period.py
+++ b/oura_api_client/api/rest_mode_period.py
@@ -1,6 +1,7 @@
 from typing import Optional, Union
 from datetime import date
 from oura_api_client.api.base import BaseRouter
+from oura_api_client.utils import build_query_params
 from oura_api_client.models.rest_mode_period import (
     RestModePeriodResponse,
     RestModePeriodModel
@@ -25,16 +26,7 @@ def get_rest_mode_period_documents(
         Returns:
             RestModePeriodResponse: Response containing rest_mode_period data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         response = self.client._make_request(
             "/usercollection/rest_mode_period", params=params
         )
diff --git a/oura_api_client/api/ring_configuration.py b/oura_api_client/api/ring_configuration.py
index ce26457..ae767d2 100644
--- a/oura_api_client/api/ring_configuration.py
+++ b/oura_api_client/api/ring_configuration.py
@@ -1,6 +1,7 @@
 from typing import Optional, Union  # Union is not strictly needed here but kept for consistency
 from datetime import date  # date is not used by ring_configuration but kept for consistency
 from oura_api_client.api.base import BaseRouter
+from oura_api_client.utils import build_query_params
 from oura_api_client.models.ring_configuration import (
     RingConfigurationResponse,
     RingConfigurationModel
@@ -31,26 +32,11 @@ def get_ring_configuration_documents(
         Returns:
             RingConfigurationResponse: Response containing ring configuration data.
         """
-        params = {}
-        if start_date:
-            if isinstance(start_date, date):
-                params["start_date"] = start_date.isoformat()
-            else:
-                params["start_date"] = start_date
-        if end_date:
-            if isinstance(end_date, date):
-                params["end_date"] = end_date.isoformat()
-            else:
-                params["end_date"] = end_date
-        if next_token:
-            params["next_token"] = next_token
-
-        # Remove None params manually as empty dict evaluates to False
-        final_params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
 
         response = self.client._make_request(
             "/usercollection/ring_configuration",
-            params=final_params if final_params else None
+            params=params if params else None
         )
         return RingConfigurationResponse(**response)
 
diff --git a/oura_api_client/api/session.py b/oura_api_client/api/session.py
index 091b058..1083b65 100644
--- a/oura_api_client/api/session.py
+++ b/oura_api_client/api/session.py
@@ -3,6 +3,7 @@
 # as per other endpoints
 from oura_api_client.api.base import BaseRouter
 from oura_api_client.models.session import SessionResponse, SessionModel
+from oura_api_client.utils import build_query_params
 
 
 class Session(BaseRouter):
@@ -25,16 +26,7 @@ def get_session_documents(
         Returns:
             SessionResponse: Response containing session data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         response = self.client._make_request(
             "/usercollection/session", params=params
         )
diff --git a/oura_api_client/api/sleep.py b/oura_api_client/api/sleep.py
index b10f2a7..df29d52 100644
--- a/oura_api_client/api/sleep.py
+++ b/oura_api_client/api/sleep.py
@@ -1,6 +1,7 @@
 from typing import Optional, Union
 from datetime import date  # Keep date for start/end_date
 from oura_api_client.api.base import BaseRouter
+from oura_api_client.utils import build_query_params
 from oura_api_client.models.sleep import (
     SleepResponse,
     SleepModel  # Updated model import
@@ -27,16 +28,7 @@ def get_sleep_documents(  # Renamed method
         Returns:
             SleepResponse: Response containing sleep data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         # Corrected endpoint URL from daily_sleep to sleep
         response = self.client._make_request(
             "/usercollection/sleep", params=params
diff --git a/oura_api_client/api/sleep_time.py b/oura_api_client/api/sleep_time.py
index affe6d6..f8ac430 100644
--- a/oura_api_client/api/sleep_time.py
+++ b/oura_api_client/api/sleep_time.py
@@ -1,6 +1,7 @@
 from typing import Optional, Union
 from datetime import date
 from oura_api_client.api.base import BaseRouter
+from oura_api_client.utils import build_query_params
 from oura_api_client.models.sleep_time import (
     SleepTimeResponse,
     SleepTimeModel
@@ -25,16 +26,7 @@ def get_sleep_time_documents(
         Returns:
             SleepTimeResponse: Response containing sleep time data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         response = self.client._make_request(
             "/usercollection/sleep_time", params=params
         )
diff --git a/oura_api_client/api/tag.py b/oura_api_client/api/tag.py
index 30b228d..f1eeb2c 100644
--- a/oura_api_client/api/tag.py
+++ b/oura_api_client/api/tag.py
@@ -2,6 +2,7 @@
 from datetime import date  # Using date for start_date and end_date
 from oura_api_client.api.base import BaseRouter
 from oura_api_client.models.tag import TagResponse, TagModel
+from oura_api_client.utils import build_query_params
 
 
 class Tag(BaseRouter):
@@ -22,16 +23,7 @@ def get_tag_documents(
         Returns:
             TagResponse: Response containing tag data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         response = self.client._make_request(
             "/usercollection/tag", params=params
         )
diff --git a/oura_api_client/api/vo2_max.py b/oura_api_client/api/vo2_max.py
index cf316f1..e4ec3ac 100644
--- a/oura_api_client/api/vo2_max.py
+++ b/oura_api_client/api/vo2_max.py
@@ -2,6 +2,7 @@
 from datetime import date
 from oura_api_client.api.base import BaseRouter
 from oura_api_client.models.vo2_max import Vo2MaxResponse, Vo2MaxModel
+from oura_api_client.utils import build_query_params
 
 
 class Vo2Max(BaseRouter):
@@ -22,16 +23,7 @@ def get_vo2_max_documents(
         Returns:
             Vo2MaxResponse: Response containing VO2 max data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         response = self.client._make_request(
             "/usercollection/vO2_max", params=params
         )
diff --git a/oura_api_client/api/workout.py b/oura_api_client/api/workout.py
index dbee601..b6c559f 100644
--- a/oura_api_client/api/workout.py
+++ b/oura_api_client/api/workout.py
@@ -2,6 +2,7 @@
 from datetime import date  # Using date for start_date and end_date
 from oura_api_client.api.base import BaseRouter
 from oura_api_client.models.workout import WorkoutResponse, WorkoutModel
+from oura_api_client.utils import build_query_params
 
 
 class Workout(BaseRouter):
@@ -22,16 +23,7 @@ def get_workout_documents(
         Returns:
             WorkoutResponse: Response containing workout data.
         """
-        if isinstance(start_date, date):
-            start_date = start_date.isoformat()
-        if isinstance(end_date, date):
-            end_date = end_date.isoformat()
-        params = {
-            "start_date": start_date if start_date else None,
-            "end_date": end_date if end_date else None,
-            "next_token": next_token if next_token else None,
-        }
-        params = {k: v for k, v in params.items() if v is not None}
+        params = build_query_params(start_date, end_date, next_token)
         response = self.client._make_request(
             "/usercollection/workout", params=params
         )
diff --git a/oura_api_client/models/webhook.py b/oura_api_client/models/webhook.py
index ba7c4c9..c207241 100644
--- a/oura_api_client/models/webhook.py
+++ b/oura_api_client/models/webhook.py
@@ -1,5 +1,5 @@
 from pydantic import BaseModel, Field
-from typing import Optional, List
+from typing import Optional
 from datetime import datetime
 from enum import Enum
 
diff --git a/oura_api_client/utils/__init__.py b/oura_api_client/utils/__init__.py
index 92cbfff..30931eb 100644
--- a/oura_api_client/utils/__init__.py
+++ b/oura_api_client/utils/__init__.py
@@ -1 +1,5 @@
 """Utility functions for the Oura API client."""
+
+from .query_params import build_query_params, convert_date_to_string
+
+__all__ = ["build_query_params", "convert_date_to_string"]
diff --git a/oura_api_client/utils/query_params.py b/oura_api_client/utils/query_params.py
new file mode 100644
index 0000000..e09ac59
--- /dev/null
+++ b/oura_api_client/utils/query_params.py
@@ -0,0 +1,51 @@
+"""Utilities for building query parameters for Oura API requests."""
+
+from datetime import date
+from typing import Optional, Union, Dict, Any
+
+
+def convert_date_to_string(date_param: Optional[Union[str, date]]) -> Optional[str]:
+    """Convert a date parameter to ISO format string if it's a date object.
+    
+    Args:
+        date_param: Date parameter that can be a string, date object, or None
+        
+    Returns:
+        ISO format date string or None
+    """
+    if isinstance(date_param, date):
+        return date_param.isoformat()
+    return date_param
+
+
+def build_query_params(
+    start_date: Optional[Union[str, date]] = None,
+    end_date: Optional[Union[str, date]] = None,
+    next_token: Optional[str] = None,
+    **kwargs: Any
+) -> Dict[str, Any]:
+    """Build query parameters dictionary for API requests.
+    
+    This function handles common query parameter patterns:
+    - Converts date objects to ISO format strings
+    - Filters out None values
+    - Supports additional parameters via kwargs
+    
+    Args:
+        start_date: Start date for filtering (string or date object)
+        end_date: End date for filtering (string or date object)
+        next_token: Token for pagination
+        **kwargs: Additional query parameters
+        
+    Returns:
+        Dictionary of query parameters with None values filtered out
+    """
+    params = {
+        "start_date": convert_date_to_string(start_date),
+        "end_date": convert_date_to_string(end_date),
+        "next_token": next_token,
+        **kwargs
+    }
+    
+    # Filter out None values
+    return {k: v for k, v in params.items() if v is not None}