diff --git a/fps_test.py b/fps_test.py
new file mode 100644
index 0000000..10e3f60
--- /dev/null
+++ b/fps_test.py
@@ -0,0 +1,114 @@
+#!/usr/bin/env python3
+"""
+fps_test.py - Misst Frame-Rate, Framegroesse und Durchsatz einer MJPEG-Quelle.
+
+Nuetzlich zum Diagnostizieren der ESP32-CAM (WLAN-/Bandbreiten-Engpass):
+ein flüssiger Stream + zuverlaessige Zaehlung braucht ausreichend FPS.
+
+Beispiele:
+    python3 fps_test.py                      # misst die App-Pipeline (/webcam_feed)
+    python3 fps_test.py --cam                 # misst die Kamera direkt (CAMERA_URL aus .env)
+    python3 fps_test.py http://192.168.10.99:81/stream
+    python3 fps_test.py --app -t 20           # App-Stream, 20 Sekunden messen
+"""
+import argparse
+import os
+import sys
+import time
+
+import requests
+
+try:
+    from dotenv import load_dotenv
+    load_dotenv()
+except ImportError:
+    pass
+
+APP_URL = "http://localhost:8080/webcam_feed"
+CAM_URL = os.environ.get("CAMERA_URL", "http://192.168.10.99:81/stream")
+
+SOI = b"\xff\xd8"   # JPEG Start-of-Image
+EOI = b"\xff\xd9"   # JPEG End-of-Image
+
+
+def measure(url: str, seconds: float) -> int:
+    print(f"Messe {seconds:.0f}s an: {url}\n", flush=True)
+    try:
+        resp = requests.get(url, stream=True, timeout=(5, 10))
+        resp.raise_for_status()
+    except requests.RequestException as exc:
+        print(f"FEHLER: {exc}")
+        return 1
+
+    buf = b""
+    frames = 0
+    total_bytes = 0
+    sizes = []
+    t0 = time.time()
+    try:
+        for chunk in resp.iter_content(chunk_size=16384):
+            buf += chunk
+            total_bytes += len(chunk)
+            while True:
+                s = buf.find(SOI)
+                e = buf.find(EOI, s + 2)
+                if s == -1 or e == -1:
+                    break
+                sizes.append(e + 2 - s)
+                buf = buf[e + 2:]
+                frames += 1
+            if time.time() - t0 >= seconds:
+                break
+    except requests.RequestException as exc:
+        print(f"Stream-Abbruch nach {frames} Frames: {exc}")
+    finally:
+        resp.close()
+
+    dt = time.time() - t0
+    if not frames:
+        print("Keine vollstaendigen Frames empfangen.")
+        return 1
+
+    fps = frames / dt
+    avg_kb = sum(sizes) / len(sizes) / 1024
+    min_kb = min(sizes) / 1024
+    max_kb = max(sizes) / 1024
+    kbs = total_bytes / dt / 1024
+    mbit = total_bytes * 8 / dt / 1e6
+
+    print(f"  Frames        : {frames} in {dt:.1f}s")
+    print(f"  FPS           : {fps:.1f}")
+    print(f"  Framegroesse  : Ø {avg_kb:.0f} KB  (min {min_kb:.0f} / max {max_kb:.0f})")
+    print(f"  Durchsatz     : {kbs:.0f} KB/s  ({mbit:.2f} Mbit/s)")
+
+    print("\n  Einschaetzung :", end=" ")
+    if fps >= 10:
+        print("fluessig - gut fuer Zaehlung. ✓")
+    elif fps >= 5:
+        print("brauchbar, aber schnelle Fahrzeuge koennen rutschen.")
+    else:
+        print("zu niedrig - WLAN-Signal/Framegroesse pruefen (kleinere Quality, naeher zum AP).")
+    if mbit < 2 and avg_kb > 40:
+        print("  Hinweis       : grosse Frames + wenig Bandbreite -> Quality-Zahl hoeher setzen ODER WLAN verbessern.")
+    return 0
+
+
+def main() -> int:
+    p = argparse.ArgumentParser(description="Misst FPS/Durchsatz einer MJPEG-Quelle.")
+    p.add_argument("url", nargs="?", help="MJPEG-URL (Default: App-Stream)")
+    p.add_argument("--app", action="store_true", help=f"App-Pipeline messen ({APP_URL})")
+    p.add_argument("--cam", action="store_true", help=f"Kamera direkt messen (CAMERA_URL: {CAM_URL})")
+    p.add_argument("-t", "--seconds", type=float, default=10, help="Messdauer in Sekunden (Default 10)")
+    args = p.parse_args()
+
+    if args.url:
+        url = args.url
+    elif args.cam:
+        url = CAM_URL
+    else:
+        url = APP_URL
+    return measure(url, args.seconds)
+
+
+if __name__ == "__main__":
+    sys.exit(main())