diff --git a/config.js b/config.js
index 350c804..d32fae5 100644
--- a/config.js
+++ b/config.js
@@ -62,6 +62,14 @@ window.CONFIG = {
     debug: 0,                     // 1 = debug panel + progress logs in the console
     // debug: 1
     credits: false,               // attribution line hidden
+
+    // Optional same-origin Overpass proxy probe. The public Overpass mirrors
+    // work directly from the browser; keep this false unless the background
+    // nginx proxy is known to be reachable and you want cached same-origin calls.
+    overpass: {
+        useProxy: false,          // true = probe /overpass/... and use it when available
+        // useProxy: true
+    },
     // credits: false
     units: { temperature: 'C' },  // 'F' for Fahrenheit
     // units: { temperature: 'F' }
diff --git a/vendor/clouds3d.js b/vendor/clouds3d.js
index d94a81f..f7982e0 100644
--- a/vendor/clouds3d.js
+++ b/vendor/clouds3d.js
@@ -3199,6 +3199,7 @@ function opProbeProxy() {
     if (_opProxyChecked) return;
     _opProxyChecked = true;
     if (location.protocol === 'file:') return;
+    if (!(window.CONFIG && window.CONFIG.overpass && window.CONFIG.overpass.useProxy)) return;
     fetch(OP_PROXY[0], {
         method: 'POST',
         headers: { 'Content-Type': 'application/x-www-form-urlencoded' },