diff --git a/main.go b/main.go
index e649b8e..f6077ad 100644
--- a/main.go
+++ b/main.go
@@ -89,14 +89,15 @@ func main() {
 		liveCfg := *app.server.appConfig // copy, not pointer
 		app.server.mu.RUnlock()
 
-		// Handle viewer server toggle.
-		if liveCfg.Auth.Viewer.Enabled && app.viewerSrv == nil {
+		// Handle viewer server toggle via viewer_port.
+		viewerOn := liveCfg.Server.ViewerPort != "" && liveCfg.Server.ViewerPort != ":0"
+		if viewerOn && app.viewerSrv == nil {
 			go func() {
 				v, err := app.server.StartViewerServer()
 				if err != nil { log.Printf("Viewer server: %v", err) }
 				app.viewerSrv = v
 			}()
-		} else if !liveCfg.Auth.Viewer.Enabled && app.viewerSrv != nil {
+		} else if !viewerOn && app.viewerSrv != nil {
 			log.Println("Stopping viewer server...")
 			app.viewerSrv.Close()
 			app.viewerSrv = nil
@@ -119,7 +120,7 @@ func main() {
 	}()
 
 	// Start viewer server only if enabled.
-	if cfg.Auth.Viewer.Enabled {
+	if cfg.Server.ViewerPort != "" && cfg.Server.ViewerPort != ":0" {
 		go func() {
 			v, err := app.server.StartViewerServer()
 			if err != nil {
@@ -128,7 +129,7 @@ func main() {
 			app.viewerSrv = v
 		}()
 	} else {
-		log.Println("Viewer server: disabled in config")
+		log.Println("Viewer server: disabled (viewer_port empty)")
 	}
 
 	select {
diff --git a/public/app.js b/public/app.js
index 51c6b4c..66a3dfb 100644
--- a/public/app.js
+++ b/public/app.js
@@ -277,7 +277,7 @@ async function renderCameraCards() {
                     <label>Username <input type="text" value="${escAttr(config?.auth?.viewer?.username || '')}" data-auth="viewer-user"></label>
                     <label>Password <input type="password" placeholder="new password" data-auth="viewer-pass"></label>
                     <div class="row" style="margin-top:8px">
-                        <label>Enable local view access <input type="checkbox" id="viewer-enable" ${config?.auth?.viewer?.enabled ? 'checked' : ''} style="width:auto"></label>
+                        <label>Enable local view access <input type="checkbox" id="viewer-enable" ${config?.server?.viewer_port ? 'checked' : ''} style="width:auto"></label>
                     </div>
                 </div>
             </div>
@@ -432,6 +432,7 @@ document.getElementById('btn-save').addEventListener('click', async () => {
         cfg.auth.master.username = masterUser;
         cfg.auth.viewer.username = viewerUser;
         cfg.auth.viewer.enabled = viewerEnabled || false;
+        cfg.server.viewer_port = viewerEnabled ? ":8090" : "";
         if (masterPass) { cfg.auth.master.password = masterPass; cfg.auth.master.enabled = true; }
         if (viewerPass) { cfg.auth.viewer.password = viewerPass; }