diff --git a/app/main.py b/app/main.py
index 62dc885..5197418 100644
--- a/app/main.py
+++ b/app/main.py
@@ -1,11 +1,20 @@
 from flask import Flask, request, Response, jsonify
 from flask_cors import CORS
+import numpy as np
 
 # Local imports from app
 from app.routes import session as session_route
 from dotenv import load_dotenv
 load_dotenv()
 
+from app.services.quality_monitor import quality_monitor_instance
+import logging
+
+log = logging.getLogger('werkzeug')
+log.setLevel(logging.ERROR)
+
+realtime_request_count = 0
+
 # Initialize Flask app and enable CORS
 app = Flask(__name__)
 CORS(app)
@@ -78,3 +87,28 @@ def batch_predict():
     if request.method == 'POST':
         return session_route.batch_predict()
     return Response('Invalid request method for route', status=405, mimetype='application/json')
+
+@app.route('/api/realtime-validation', methods=['POST', 'OPTIONS'])
+def realtime_validation():
+    global realtime_request_count
+    
+    if request.method == 'OPTIONS':
+        return '', 200
+    try:
+        data = request.get_json()
+        prediction = data.get('prediction')
+
+        # Increment count to throttle logs from being spammed on terminal
+        realtime_request_count += 1
+        should_print = (realtime_request_count % 30 == 0)
+
+        # Delegate the actual processing logic and state management to the service
+        result = quality_monitor_instance.process_prediction(prediction, should_print=should_print)
+        
+        return jsonify(result)
+        
+    except Exception as e:
+        import traceback
+        print(f"Server Error: {e}")
+        traceback.print_exc()
+        return jsonify({'error': str(e)}), 500
diff --git a/app/services/gaze_tracker.py b/app/services/gaze_tracker.py
index 8baa74c..da238d5 100644
--- a/app/services/gaze_tracker.py
+++ b/app/services/gaze_tracker.py
@@ -116,7 +116,6 @@
     "mae": make_scorer(mean_absolute_error),
 }
 
-
 def squash(v, limit=1.0):
     """Squash não-linear estilo WebGazer"""
     return np.tanh(v / limit)
@@ -241,7 +240,6 @@ def predict(data, k, model_X, model_Y):
     # Calculate the average accuracy (eculidian distance)
     accuracy_xy = df_data.groupby("True XY").apply(func_total_accuracy)
     
-
     # Create a dictionary to store the data
     data = {}
     grouped = df_data.groupby("True XY")
@@ -269,7 +267,6 @@ def predict(data, k, model_X, model_Y):
     # Return the data
     return data
 
-
 def predict_new_data_simple(
     calib_csv_path,
     predict_csv_path,
@@ -414,10 +411,13 @@ def predict_new_data_simple(
     
     y_pred_y = y_pred_y * Y_GAIN
 
+
     # ============================
     # PREDICTION LOOP (WebGazer)
     # ============================
     predictions = []
+    window_size = 30
+
 
     for i in range(len(y_pred_x)):
         # baseline dinâmico
diff --git a/app/services/quality_monitor.py b/app/services/quality_monitor.py
new file mode 100644
index 0000000..cb49981
--- /dev/null
+++ b/app/services/quality_monitor.py
@@ -0,0 +1,81 @@
+import numpy as np
+import math
+
+class QualityMonitor:
+    def __init__(self, window_size=50, precision_cutoff_degrees=1.0, screen_dpi=110, user_distance_mm=600):
+        self.window_size = window_size
+        self.precision_cutoff_degrees = precision_cutoff_degrees
+        self.screen_dpi = screen_dpi
+        self.user_distance_mm = user_distance_mm
+        self.x_center_coords = []
+        self.y_center_coords = []
+
+    def pixels_to_degrees(self, pixels, ppi=96.0, distance_cm=60.0):
+        # pixels in one centimeter calculation
+        pixels_per_cm = ppi / 2.54
+
+        # Convert the pixel distance to physical size in centimeters
+        size_cm = pixels / pixels_per_cm
+
+        # Visual angle calculation
+        angle_rad = 2 * np.arctan(size_cm / (2 * distance_cm))
+        angle_deg = np.degrees(angle_rad)
+
+        return angle_deg
+
+    def calculate_rms_s2s_precision(self, x_coords, y_coords):
+        if len(x_coords) < 2:
+            return 0.0
+        
+        x = np.array(x_coords)
+        y = np.array(y_coords)
+
+        # Calculate dfferences between consecutive points
+        dx = np.diff(x)
+        dy = np.diff(y)
+
+        # Calculate squared distances between consecutive samples
+        distances = np.sqrt(dx**2 + dy**2)
+
+        # Root Mean Square calculation
+        rms_s2s_px = np.sqrt(np.mean(distances**2))
+        return rms_s2s_px
+
+    def process_prediction(self, prediction, should_print=True):
+
+        if not prediction or len(prediction) == 0:
+            return {"status": "no_prediction"}
+        
+        face = prediction[0]
+        annotations = face.get("annotations", {})
+        right_iris = annotations.get("rightEyeIris", [])
+
+        if not right_iris:
+            return {"status": "no_prediction"}
+        
+        right_iris_center = right_iris[0]
+        x_center = right_iris_center[0]
+        y_center = right_iris_center[1]
+
+        self.x_center_coords.append(x_center)
+        self.y_center_coords.append(y_center)
+
+        # Keep only the last N points
+        if len(self.x_center_coords) > self.window_size:
+            self.x_center_coords.pop(0)
+            self.y_center_coords.pop(0)
+
+        # RMS-S2S metric calculation
+        precision_px = self.calculate_rms_s2s_precision(self.x_center_coords, self.y_center_coords)
+        precision_deg = self.pixels_to_degrees(precision_px)
+
+        status = "good" if precision_deg < self.precision_cutoff_degrees else "poor"
+        points_collected = len(self.x_center_coords)
+
+        if should_print:
+            print(f"Coordinates: X={x_center:.2f}, Y={y_center:.2f} | Precision: {precision_deg:.2f}° (RMS-S2S) | Status: {status}")
+            
+        return {"status": status, "precision_degrees": float(precision_deg), "precision_pixels": float(precision_px), "points_collected": points_collected}
+
+# Initialize with standard 0.5 degrees cutoff
+quality_monitor_instance = QualityMonitor(window_size=50, precision_cutoff_degrees=0.5)