diff --git a/React/Base/RCTConvert.m b/React/Base/RCTConvert.m
index 7bae9fbc5..fcb8ec167 100644
--- a/React/Base/RCTConvert.m
+++ b/React/Base/RCTConvert.m
@@ -89,7 +89,14 @@ RCT_CUSTOM_CONVERTER(NSData *, NSData, [json dataUsingEncoding:NSUTF8StringEncod
 
     // Check if it has a scheme
     if ([path rangeOfString:@":"].location != NSNotFound) {
-      path = [path stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
+      NSMutableCharacterSet *urlAllowedCharacterSet = [NSMutableCharacterSet new];
+      [urlAllowedCharacterSet formUnionWithCharacterSet:[NSCharacterSet URLUserAllowedCharacterSet]];
+      [urlAllowedCharacterSet formUnionWithCharacterSet:[NSCharacterSet URLPasswordAllowedCharacterSet]];
+      [urlAllowedCharacterSet formUnionWithCharacterSet:[NSCharacterSet URLHostAllowedCharacterSet]];
+      [urlAllowedCharacterSet formUnionWithCharacterSet:[NSCharacterSet URLPathAllowedCharacterSet]];
+      [urlAllowedCharacterSet formUnionWithCharacterSet:[NSCharacterSet URLQueryAllowedCharacterSet]];
+      [urlAllowedCharacterSet formUnionWithCharacterSet:[NSCharacterSet URLFragmentAllowedCharacterSet]];
+      path = [path stringByAddingPercentEncodingWithAllowedCharacters:urlAllowedCharacterSet];
       URL = [NSURL URLWithString:path];
       if (URL) {
         return URL;
diff --git a/React/DevSupport/RCTInspectorDevServerHelper.mm b/React/DevSupport/RCTInspectorDevServerHelper.mm
index 2901b6833..e157ef5da 100644
--- a/React/DevSupport/RCTInspectorDevServerHelper.mm
+++ b/React/DevSupport/RCTInspectorDevServerHelper.mm
@@ -33,8 +33,8 @@ static NSString *getServerHost(NSURL *bundleURL, NSNumber *port)
 static NSURL *getInspectorDeviceUrl(NSURL *bundleURL)
 {
   NSNumber *inspectorProxyPort = @8082;
-  NSString *escapedDeviceName = [[[UIDevice currentDevice] name] stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
-  NSString *escapedAppName = [[[NSBundle mainBundle] bundleIdentifier] stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
+  NSString *escapedDeviceName = [[[UIDevice currentDevice] name] stringByAddingPercentEncodingWithAllowedCharacters:NSCharacterSet.URLQueryAllowedCharacterSet];
+  NSString *escapedAppName = [[[NSBundle mainBundle] bundleIdentifier] stringByAddingPercentEncodingWithAllowedCharacters:NSCharacterSet.URLQueryAllowedCharacterSet];
   return [NSURL URLWithString:[NSString stringWithFormat:@"http://%@/inspector/device?name=%@&app=%@",
                                                         getServerHost(bundleURL, inspectorProxyPort),
                                                         escapedDeviceName,
@@ -44,8 +44,8 @@ static NSURL *getInspectorDeviceUrl(NSURL *bundleURL)
 static NSURL *getAttachDeviceUrl(NSURL *bundleURL, NSString *title)
 {
   NSNumber *metroBundlerPort = @8081;
-  NSString *escapedDeviceName = [[[UIDevice currentDevice] name] stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
-  NSString *escapedAppName = [[[NSBundle mainBundle] bundleIdentifier] stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
+  NSString *escapedDeviceName = [[[UIDevice currentDevice] name] stringByAddingPercentEncodingWithAllowedCharacters:NSCharacterSet.URLHostAllowedCharacterSet];
+  NSString *escapedAppName = [[[NSBundle mainBundle] bundleIdentifier] stringByAddingPercentEncodingWithAllowedCharacters:NSCharacterSet.URLHostAllowedCharacterSet];
   return [NSURL URLWithString:[NSString stringWithFormat:@"http://%@/attach-debugger-nuclide?title=%@&device=%@&app=%@",
                                getServerHost(bundleURL, metroBundlerPort),
                                title,
diff --git a/React/Views/RCTWebView.m b/React/Views/RCTWebView.m
index a634efc3d..8f61e3804 100644
--- a/React/Views/RCTWebView.m
+++ b/React/Views/RCTWebView.m
@@ -247,7 +247,7 @@ RCT_NOT_IMPLEMENTED(- (instancetype)initWithCoder:(NSCoder *)aDecoder)
   if (isJSNavigation && [request.URL.host isEqualToString:kPostMessageHost]) {
     NSString *data = request.URL.query;
     data = [data stringByReplacingOccurrencesOfString:@"+" withString:@" "];
-    data = [data stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
+    data = [data stringByAddingPercentEncodingWithAllowedCharacters:NSCharacterSet.URLQueryAllowedCharacterSet];
 
     NSMutableDictionary<NSString *, id> *event = [self baseEvent];
     [event addEntriesFromDictionary: @{