diff --git a/server/__pycache__/flask_app.cpython-313.pyc b/server/__pycache__/flask_app.cpython-313.pyc
index 0b8392e..ab35a93 100644
Binary files a/server/__pycache__/flask_app.cpython-313.pyc and b/server/__pycache__/flask_app.cpython-313.pyc differ
diff --git a/server/core/config.py b/server/core/config.py
index 3b62e57..60742ad 100644
--- a/server/core/config.py
+++ b/server/core/config.py
@@ -28,3 +28,8 @@ ELEVATION_PROBE_TTL_SEC = float(
 ELEVATION_CONNECT_TIMEOUT = float(
     os.environ.get("LORATESTER_ELEVATION_TIMEOUT", "8")
 )
+RF_API_URL = os.environ.get(
+    "LORATESTER_RF_API_URL",
+    "http://127.0.0.1:5603",
+).rstrip("/")
+RF_API_TIMEOUT = float(os.environ.get("LORATESTER_RF_API_TIMEOUT", "30"))
diff --git a/server/flask_app.py b/server/flask_app.py
index dba4bfb..17926a9 100644
--- a/server/flask_app.py
+++ b/server/flask_app.py
@@ -3,11 +3,12 @@
 import time
 from pathlib import Path
 
-from flask import Flask, jsonify, request, send_from_directory
+import httpx
+from flask import Flask, Response, jsonify, request, send_from_directory
 from flask_cors import CORS
 
 from core.auth import ANDROID_CLIENT_HEADER, is_android_client
-from core.config import HOST, PORT
+from core.config import HOST, PORT, RF_API_TIMEOUT, RF_API_URL
 from core.models import ChatIn, TelemetryIn
 from core import storage
 from core.telemetry_body import telemetry_from_body
@@ -27,6 +28,38 @@ def index():
     return resp
 
 
+@app.route("/api/rf/<path:rf_path>", methods=["GET", "POST"])
+def rf_api_proxy(rf_path: str):
+    target = f"{RF_API_URL}/{rf_path.lstrip('/')}"
+    if request.query_string:
+        target = f"{target}?{request.query_string.decode('utf-8', errors='ignore')}"
+    try:
+        with httpx.Client(timeout=RF_API_TIMEOUT) as client:
+            upstream = client.request(
+                request.method,
+                target,
+                content=request.get_data() if request.method != "GET" else None,
+                headers={
+                    "Accept": request.headers.get("Accept", "application/json"),
+                    "Content-Type": request.headers.get(
+                        "Content-Type", "application/json"
+                    ),
+                },
+            )
+    except httpx.RequestError as e:
+        return jsonify({
+            "error": "RF API unavailable",
+            "detail": str(e),
+            "target": target,
+        }), 502
+
+    return Response(
+        upstream.content,
+        status=upstream.status_code,
+        content_type=upstream.headers.get("content-type", "application/json"),
+    )
+
+
 @app.post("/api/telemetry")
 def post_telemetry():
     if not is_android_client(request.headers):
diff --git a/server/static/index.html b/server/static/index.html
index ff3213c..1aca53d 100644
--- a/server/static/index.html
+++ b/server/static/index.html
@@ -2054,8 +2054,7 @@
     }
 
     function defaultApiDebugBase() {
-      const port = location.port === '5603' ? '' : ':5603';
-      return `${location.protocol}//${location.hostname}${port}`;
+      return '/api/rf';
     }
 
     function apiDebugNumber(id, fallback = null) {
@@ -2299,7 +2298,7 @@
       } catch (e) {
         apiDebugSetStatus(`Ошибка запроса: ${e.message || e}`, true);
         apiDebugSetOutput(e.response ||
-          'Проверьте API base URL, доступность порта и CORS. Для API на том же сервере обычно подходит порт 5603.');
+          'Проверьте API base URL. По умолчанию используется same-origin proxy /api/rf.');
         apiDebugSetSummary('Расчёт не выполнен.');
       }
     }
@@ -2407,7 +2406,7 @@
       } catch (e) {
         apiDebugSetStatus(`Ошибка расчёта линии: ${e.message || e}`, true);
         apiDebugSetOutput(e.response ||
-          'Проверьте API base URL, доступность порта и CORS. Для API на том же сервере обычно подходит порт 5603.');
+          'Проверьте API base URL. По умолчанию используется same-origin proxy /api/rf.');
         apiDebugSetSummary('Расчёт линии не выполнен.');
       }
     }