diff --git a/queue_separation/src/queue_separation/main.py b/queue_separation/src/queue_separation/main.py
new file mode 100644
index 0000000..b2edb8c
--- /dev/null
+++ b/queue_separation/src/queue_separation/main.py
@@ -0,0 +1,106 @@
+from __future__ import annotations
+import json
+import random
+import statistics
+import time
+from dataclasses import dataclass, asdict
+from typing import List, Dict, Any
+import logging
+import pandas as pd
+
+
+# Configure logging for CI readiness
+logging.basicConfig(
+    level=logging.INFO,
+    format='%(asctime)s [%(levelname)s] %(message)s'
+)
+logger = logging.getLogger(__name__)
+
+
+class SimulationError(Exception):
+    """Custom exception for simulation errors."""
+    pass
+
+
+@dataclass
+class PerformanceMetrics:
+    retry_tail_p99: float
+    bandwidth: float
+    hotspot_percentage: float
+
+    def to_dict(self) -> Dict[str, float]:
+        return asdict(self)
+
+
+def _validate_jobs(jobs: List[Dict[str, Any]], label: str) -> None:
+    if not isinstance(jobs, list):
+        raise ValueError(f"{label} must be a list of dicts, got {type(jobs)}")
+    for job in jobs:
+        if not isinstance(job, dict):
+            raise ValueError(f"Each job in {label} must be a dict, got {type(job)}")
+        if 'runtime' not in job:
+            raise ValueError(f"Each job in {label} must contain a 'runtime' key")
+        if not isinstance(job['runtime'], (int, float)):
+            raise ValueError(f"Job runtime in {label} must be numeric, got {type(job['runtime'])}")
+
+
+def simulate_queue_separation(
+    jobs: List[Dict[str, Any]],
+    hotspot_queue: List[Dict[str, Any]],
+    main_queue: List[Dict[str, Any]]
+) -> Dict[str, float]:
+    """Führt eine Simulation der Queue-Entkopplung durch und liefert Performance-Metriken.
+
+    Args:
+        jobs: Liste von Job-Objekten mit Metadaten zur Laufzeit und zum Queue-Typ.
+        hotspot_queue: Separate Queue für Hotspot-Jobs.
+        main_queue: Hauptqueue für reguläre Jobs.
+
+    Returns:
+        dict: JSON-kompatible Struktur mit Messwerten wie retry_tail_p99, bandwidth, hotspot_percentage.
+    """
+    start_ts = time.time()
+
+    try:
+        _validate_jobs(jobs, 'jobs')
+        _validate_jobs(hotspot_queue, 'hotspot_queue')
+        _validate_jobs(main_queue, 'main_queue')
+    except ValueError as e:
+        logger.error(f"Validation failed: {e}")
+        raise SimulationError(f"Input validation error: {e}") from e
+
+    if len(jobs) == 0:
+        raise SimulationError("No jobs provided for simulation.")
+
+    # Simulate variability in job latencies and queue effects
+    all_runtimes = [j['runtime'] for j in jobs]
+    retries = [r * random.uniform(0.9, 1.2) for r in all_runtimes]
+
+    retry_tail_p99 = statistics.quantiles(retries, n=100)[-1]
+
+    # Compute total bandwidth as inverse relation to total processing time
+    total_runtime = sum(all_runtimes)
+    bandwidth = len(jobs) / (total_runtime + 1e-6)
+
+    hotspot_percentage = (len(hotspot_queue) / len(jobs)) * 100.0
+
+    # Aggregate via pandas for future extensions
+    df = pd.DataFrame({
+        'runtime': all_runtimes,
+        'retry_runtime': retries
+    })
+    mean_runtime = df['runtime'].mean()
+    logger.info(f"Mean runtime: {mean_runtime:.3f}s | Tail P99: {retry_tail_p99:.3f}s | Bandwidth: {bandwidth:.3f} jobs/s")
+
+    metrics = PerformanceMetrics(
+        retry_tail_p99=retry_tail_p99,
+        bandwidth=bandwidth,
+        hotspot_percentage=hotspot_percentage
+    )
+
+    duration = time.time() - start_ts
+    logger.debug(f"Simulation duration: {duration:.2f}s")
+
+    assert all(v >= 0 for v in metrics.to_dict().values()), "Metrics must be non-negative"
+
+    return metrics.to_dict()