diff --git a/src/objc/ModalWebViewController.h b/src/objc/ModalWebViewController.h
index 0bb6d58..dc8002f 100644
--- a/src/objc/ModalWebViewController.h
+++ b/src/objc/ModalWebViewController.h
@@ -14,4 +14,5 @@
 - (void)openRequest:(NSMutableURLRequest *)request;
 - (NSDictionary *)getBrowserCookiesForCurrentUrl;
 - (NSDictionary *)getBrowserCookiesForDomain:(NSString *)domain;
+- (NSString *)evalJs:(NSString *)js timeout:(double)timeoutSeconds;
 @end
diff --git a/src/objc/ModalWebViewController.mm b/src/objc/ModalWebViewController.mm
index e63e36a..c4b0432 100644
--- a/src/objc/ModalWebViewController.mm
+++ b/src/objc/ModalWebViewController.mm
@@ -34,6 +34,8 @@ - (void)viewDidLoad {
   configuration.websiteDataStore = self.websiteDataStore;
 
   
+  WKUserContentController *contentController = [[WKUserContentController alloc] init];
+
   if (self.interceptRequests) {
     NSString *injectedJS =
     @"(function() {\n"
@@ -122,20 +124,15 @@ - (void)viewDidLoad {
     "    Error.prototype = OriginalError.prototype;\n"
     "    Object.setPrototypeOf(Error, OriginalError);\n"
     "})();\n";
-    
-    
+
     WKUserScript *userScript = [[WKUserScript alloc] initWithSource:injectedJS
                                                       injectionTime:WKUserScriptInjectionTimeAtDocumentStart
                                                    forMainFrameOnly:NO];
-    
-    WKUserContentController *contentController = [[WKUserContentController alloc] init];
     [contentController addUserScript:userScript];
-    configuration.userContentController = contentController;
     [contentController addScriptMessageHandler:self name:@"interceptedRequestHandler"];
-  } else {
-    WKUserContentController *contentController = [[WKUserContentController alloc] init];
-    configuration.userContentController = contentController;
   }
+
+  configuration.userContentController = contentController;
   
   // --- Now create the web view ---
   self.webView = [[WKWebView alloc] initWithFrame:self.view.bounds configuration:configuration];
@@ -324,6 +321,52 @@ - (NSDictionary *)getBrowserCookiesForCurrentUrl {
   return result;
 }
 
+- (NSString *)evalJs:(NSString *)js timeout:(double)timeoutSeconds {
+  dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
+  __block NSString *result = nil;
+
+  // callAsyncJavaScript treats `js` as the body of an async function, so
+  // `return`, `await`, and top-level Promises all work without any wrapping.
+  // WebKit natively awaits any returned thenable before calling the completion handler,
+  // so we don't need a message-handler bridge or a custom JS wrapper.
+  WKWebView *webView = self.webView;
+  void (^evalBlock)(void) = ^{
+    [webView callAsyncJavaScript:js
+                       arguments:@{}
+                         inFrame:nil
+                  inContentWorld:WKContentWorld.pageWorld
+               completionHandler:^(id _Nullable jsResult, NSError *_Nullable error) {
+      if (error != nil) {
+        NSDictionary *errorDict = @{@"error" : error.localizedDescription};
+        NSData *jsonData = [NSJSONSerialization dataWithJSONObject:errorDict options:0 error:nil];
+        result = jsonData ? [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding]
+                          : @"{\"error\":\"unknown error\"}";
+      } else {
+        id value = jsResult ?: [NSNull null];
+        NSDictionary *resultDict = @{@"result" : value};
+        NSData *jsonData = [NSJSONSerialization dataWithJSONObject:resultDict options:0 error:nil];
+        result = jsonData ? [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding]
+                          : @"{\"result\":null}";
+      }
+      dispatch_semaphore_signal(semaphore);
+    }];
+  };
+
+  if ([NSThread isMainThread]) {
+    evalBlock();
+  } else {
+    dispatch_async(dispatch_get_main_queue(), evalBlock);
+  }
+
+  // timeout == 0: fire-and-forget (DISPATCH_TIME_NOW = don't wait, script still runs)
+  dispatch_time_t deadline = timeoutSeconds == 0.0
+      ? DISPATCH_TIME_NOW
+      : dispatch_time(DISPATCH_TIME_NOW, (int64_t)(timeoutSeconds * NSEC_PER_SEC));
+
+  BOOL timedOut = dispatch_semaphore_wait(semaphore, deadline) != 0;
+  return timedOut ? @"{\"result\":null}" : (result ?: @"{\"result\":null}");
+}
+
 - (void)updateCapturedCookiesWithCompletion:(void (^)(void))completion {
   WKHTTPCookieStore *cookieStore =
       self.webView.configuration.websiteDataStore.httpCookieStore;
@@ -526,14 +569,14 @@ - (void)userContentController:(WKUserContentController *)userContentController
     NSDictionary *payload = message.body;
     NSString *requestType = payload[@"requestType"];
     NSDictionary *data = payload[@"data"];
-    
+
     NSDictionary *event = @{
       @"event" : @"intercepted_request",
       @"request_type" : requestType,
       @"data" : data,
       @"id" : [self nextId]
     };
-    
+
     NSError *error = nil;
     NSData *jsonData = [NSJSONSerialization dataWithJSONObject:event
                                                        options:0
diff --git a/src/objc/OpacityObjCWrapper.mm b/src/objc/OpacityObjCWrapper.mm
index 0b91ed9..f72f050 100644
--- a/src/objc/OpacityObjCWrapper.mm
+++ b/src/objc/OpacityObjCWrapper.mm
@@ -72,7 +72,7 @@ + (int)initialize:(NSString *)api_key
       is_location_services_enabled, is_wifi_connected, is_rooted,
       is_app_foregrounded, get_device_locale, get_screen_width,
       get_screen_height, get_screen_density, get_screen_dpi, get_device_cpu,
-      get_device_codename, ios_webview_change_url);
+      get_device_codename, ios_webview_change_url, ios_eval_js);
 
 
   char *err;
diff --git a/src/objc/helper_functions.h b/src/objc/helper_functions.h
index 7275e87..f57cc4e 100644
--- a/src/objc/helper_functions.h
+++ b/src/objc/helper_functions.h
@@ -12,6 +12,7 @@ extern "C"
     const char *ios_get_browser_cookies_for_domain(const char *domain);
     const char *ios_get_browser_cookies_for_current_url();
     void ios_webview_change_url(const char *url);
+    const char *ios_eval_js(const char *js, double timeout_in_seconds);
 
     // Device information functions
     double get_battery_level();
diff --git a/src/objc/helper_functions.mm b/src/objc/helper_functions.mm
index e3a49f4..1b424ce 100644
--- a/src/objc/helper_functions.mm
+++ b/src/objc/helper_functions.mm
@@ -140,6 +140,24 @@ void ios_webview_change_url(const char *url) {
   });
 }
 
+const char *ios_eval_js(const char *js, double timeout_in_seconds) {
+  if (modalWebVC == nil) {
+    return strdup("{\"error\":\"browser not open\"}");
+  }
+
+  NSString *jsString = [NSString stringWithUTF8String:js];
+  if (jsString == nil) {
+    return strdup("{\"error\":\"invalid js string\"}");
+  }
+
+  NSString *result = [modalWebVC evalJs:jsString timeout:timeout_in_seconds];
+  if (result == nil) {
+    return strdup("{\"error\":\"nil result\"}");
+  }
+
+  return strdup([result UTF8String]);
+}
+
 const char *ios_get_browser_cookies_for_domain(const char *domain) {
   if (modalWebVC == nil) {
     return nullptr;
diff --git a/src/objc/sdk.h b/src/objc/sdk.h
index 9cf4e50..1e9e14f 100644
--- a/src/objc/sdk.h
+++ b/src/objc/sdk.h
@@ -86,6 +86,8 @@ typedef const char *(*GetDeviceCodenameFn)(void);
 
 typedef void (*IosWebviewChangeUrlFn)(const char*);
 
+typedef const char *(*IosEvalJsFn)(const char*, double);
+
 
 
 
@@ -243,7 +245,8 @@ void register_ios_callbacks(IosPrepareRequestFn ios_prepare_request,
                             GetScreenDpiFn get_screen_dpi,
                             GetDeviceCpuFn get_device_cpu,
                             GetDeviceCodenameFn get_device_codename,
-                            IosWebviewChangeUrlFn ios_webview_change_url);
+                            IosWebviewChangeUrlFn ios_webview_change_url,
+                            IosEvalJsFn ios_eval_js);
 
 extern void secure_set(const char *key, const char *value);