diff --git a/nan_callbacks_12_inl.h b/nan_callbacks_12_inl.h
index ff3b654d..835580dc 100644
--- a/nan_callbacks_12_inl.h
+++ b/nan_callbacks_12_inl.h
@@ -179,13 +179,30 @@ class PropertyCallbackInfo {
 };
 
 namespace imp {
+
+// Recent V8 versions (currently Chromium/Electron's V8 snapshot; not yet in
+// any released Node) gained an ExternalPointerTypeTag parameter on
+// v8::External::Value().  Detect that API via the V8_EXTERNAL_POINTER_TAG_COUNT
+// macro (defined in <v8-internal.h> alongside the new signature) rather than a
+// V8_MAJOR_VERSION cutoff, since Node and Chromium ship divergent V8
+// snapshots under the same major version.  Externals created by nan use
+// kExternalPointerTypeTagDefault (see imp::NewExternal in
+// nan_implementation_12_inl.h), so the same tag is used here on read.
+inline void* GetExternalPointer(v8::Local<v8::External> ext) {
+#ifdef V8_EXTERNAL_POINTER_TAG_COUNT
+  return ext->Value(v8::kExternalPointerTypeTagDefault);
+#else
+  return ext->Value();
+#endif
+}
+
 static
 void FunctionCallbackWrapper(const v8::FunctionCallbackInfo<v8::Value> &info) {
   v8::Local<v8::Object> obj = info.Data().As<v8::Object>();
   FunctionCallback callback = reinterpret_cast<FunctionCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kFunctionIndex)
-          .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kFunctionIndex)
+          .As<v8::Value>().As<v8::External>())));
   FunctionCallbackInfo<v8::Value>
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   callback(cbinfo);
@@ -203,8 +220,8 @@ void GetterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   GetterCallback callback = reinterpret_cast<GetterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kGetterIndex)
-          .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kGetterIndex)
+          .As<v8::Value>().As<v8::External>())));
   callback(property.As<v8::String>(), cbinfo);
 }
 
@@ -221,8 +238,8 @@ void SetterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   SetterCallback callback = reinterpret_cast<SetterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kSetterIndex)
-          .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kSetterIndex)
+          .As<v8::Value>().As<v8::External>())));
   callback(property.As<v8::String>(), value, cbinfo);
 }
 
@@ -240,8 +257,8 @@ void GetterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   GetterCallback callback = reinterpret_cast<GetterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kGetterIndex)
-          .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kGetterIndex)
+          .As<v8::Value>().As<v8::External>())));
   callback(property, cbinfo);
 }
 
@@ -258,8 +275,8 @@ void SetterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   SetterCallback callback = reinterpret_cast<SetterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kSetterIndex)
-          .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kSetterIndex)
+          .As<v8::Value>().As<v8::External>())));
   callback(property, value, cbinfo);
 }
 
@@ -282,8 +299,8 @@ v8::Intercepted PropertyGetterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   PropertyGetterCallback callback = reinterpret_cast<PropertyGetterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kPropertyGetterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kPropertyGetterIndex)
+              .As<v8::Value>().As<v8::External>())));
   return callback(property.As<v8::String>(), cbinfo);
 }
 
@@ -300,8 +317,8 @@ v8::Intercepted PropertySetterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   PropertySetterCallback callback = reinterpret_cast<PropertySetterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kPropertySetterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kPropertySetterIndex)
+              .As<v8::Value>().As<v8::External>())));
   return callback(property.As<v8::String>(), value, cbinfo);
 }
 
@@ -320,8 +337,8 @@ void PropertyGetterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   PropertyGetterCallback callback = reinterpret_cast<PropertyGetterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kPropertyGetterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kPropertyGetterIndex)
+              .As<v8::Value>().As<v8::External>())));
   callback(property.As<v8::String>(), cbinfo);
 }
 
@@ -338,8 +355,8 @@ void PropertySetterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   PropertySetterCallback callback = reinterpret_cast<PropertySetterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kPropertySetterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kPropertySetterIndex)
+              .As<v8::Value>().As<v8::External>())));
   callback(property.As<v8::String>(), value, cbinfo);
 }
 
@@ -357,8 +374,8 @@ void PropertyEnumeratorCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   PropertyEnumeratorCallback callback =
       reinterpret_cast<PropertyEnumeratorCallback>(reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kPropertyEnumeratorIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kPropertyEnumeratorIndex)
+              .As<v8::Value>().As<v8::External>())));
   callback(cbinfo);
 }
 
@@ -376,8 +393,8 @@ v8::Intercepted PropertyDeleterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   PropertyDeleterCallback callback = reinterpret_cast<PropertyDeleterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kPropertyDeleterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kPropertyDeleterIndex)
+              .As<v8::Value>().As<v8::External>())));
   return callback(property.As<v8::String>(), cbinfo);
 }
 
@@ -394,8 +411,8 @@ v8::Intercepted PropertyQueryCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   PropertyQueryCallback callback = reinterpret_cast<PropertyQueryCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kPropertyQueryIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kPropertyQueryIndex)
+              .As<v8::Value>().As<v8::External>())));
   return callback(property.As<v8::String>(), cbinfo);
 }
 
@@ -411,8 +428,8 @@ void PropertyDeleterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   PropertyDeleterCallback callback = reinterpret_cast<PropertyDeleterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kPropertyDeleterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kPropertyDeleterIndex)
+              .As<v8::Value>().As<v8::External>())));
   callback(property.As<v8::String>(), cbinfo);
 }
 
@@ -428,8 +445,8 @@ void PropertyQueryCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   PropertyQueryCallback callback = reinterpret_cast<PropertyQueryCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kPropertyQueryIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kPropertyQueryIndex)
+              .As<v8::Value>().As<v8::External>())));
   callback(property.As<v8::String>(), cbinfo);
 }
 
@@ -446,8 +463,8 @@ void PropertyGetterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   PropertyGetterCallback callback = reinterpret_cast<PropertyGetterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kPropertyGetterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kPropertyGetterIndex)
+              .As<v8::Value>().As<v8::External>())));
   callback(property, cbinfo);
 }
 
@@ -464,8 +481,8 @@ void PropertySetterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   PropertySetterCallback callback = reinterpret_cast<PropertySetterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kPropertySetterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kPropertySetterIndex)
+              .As<v8::Value>().As<v8::External>())));
   callback(property, value, cbinfo);
 }
 
@@ -482,8 +499,8 @@ void PropertyEnumeratorCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   PropertyEnumeratorCallback callback =
       reinterpret_cast<PropertyEnumeratorCallback>(reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kPropertyEnumeratorIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kPropertyEnumeratorIndex)
+              .As<v8::Value>().As<v8::External>())));
   callback(cbinfo);
 }
 
@@ -499,8 +516,8 @@ void PropertyDeleterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   PropertyDeleterCallback callback = reinterpret_cast<PropertyDeleterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kPropertyDeleterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kPropertyDeleterIndex)
+              .As<v8::Value>().As<v8::External>())));
   callback(property, cbinfo);
 }
 
@@ -516,8 +533,8 @@ void PropertyQueryCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   PropertyQueryCallback callback = reinterpret_cast<PropertyQueryCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kPropertyQueryIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kPropertyQueryIndex)
+              .As<v8::Value>().As<v8::External>())));
   callback(property, cbinfo);
 }
 
@@ -535,8 +552,8 @@ v8::Intercepted IndexGetterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   IndexGetterCallback callback = reinterpret_cast<IndexGetterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kIndexPropertyGetterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kIndexPropertyGetterIndex)
+              .As<v8::Value>().As<v8::External>())));
   return callback(index, cbinfo);
 }
 
@@ -553,8 +570,8 @@ v8::Intercepted IndexSetterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   IndexSetterCallback callback = reinterpret_cast<IndexSetterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kIndexPropertySetterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kIndexPropertySetterIndex)
+              .As<v8::Value>().As<v8::External>())));
   return callback(index, value, cbinfo);
 }
 
@@ -572,8 +589,8 @@ void IndexGetterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   IndexGetterCallback callback = reinterpret_cast<IndexGetterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kIndexPropertyGetterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kIndexPropertyGetterIndex)
+              .As<v8::Value>().As<v8::External>())));
   callback(index, cbinfo);
 }
 
@@ -589,8 +606,8 @@ void IndexSetterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   IndexSetterCallback callback = reinterpret_cast<IndexSetterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kIndexPropertySetterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kIndexPropertySetterIndex)
+              .As<v8::Value>().As<v8::External>())));
   callback(index, value, cbinfo);
 }
 
@@ -609,9 +626,9 @@ void IndexEnumeratorCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   IndexEnumeratorCallback callback = reinterpret_cast<IndexEnumeratorCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(
+          imp::GetExternalPointer(obj->GetInternalField(
               kIndexPropertyEnumeratorIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+              .As<v8::Value>().As<v8::External>())));
   callback(cbinfo);
 }
 
@@ -628,8 +645,8 @@ v8::Intercepted IndexDeleterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   IndexDeleterCallback callback = reinterpret_cast<IndexDeleterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kIndexPropertyDeleterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kIndexPropertyDeleterIndex)
+              .As<v8::Value>().As<v8::External>())));
   return callback(index, cbinfo);
 }
 
@@ -644,8 +661,8 @@ v8::Intercepted IndexQueryCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   IndexQueryCallback callback = reinterpret_cast<IndexQueryCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kIndexPropertyQueryIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kIndexPropertyQueryIndex)
+              .As<v8::Value>().As<v8::External>())));
   return callback(index, cbinfo);
 }
 
@@ -660,8 +677,8 @@ void IndexDeleterCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   IndexDeleterCallback callback = reinterpret_cast<IndexDeleterCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kIndexPropertyDeleterIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kIndexPropertyDeleterIndex)
+              .As<v8::Value>().As<v8::External>())));
   callback(index, cbinfo);
 }
 
@@ -676,8 +693,8 @@ void IndexQueryCallbackWrapper(
       cbinfo(info, obj->GetInternalField(kDataIndex).As<v8::Value>());
   IndexQueryCallback callback = reinterpret_cast<IndexQueryCallback>(
       reinterpret_cast<intptr_t>(
-          obj->GetInternalField(kIndexPropertyQueryIndex)
-              .As<v8::Value>().As<v8::External>()->Value()));
+          imp::GetExternalPointer(obj->GetInternalField(kIndexPropertyQueryIndex)
+              .As<v8::Value>().As<v8::External>())));
   callback(index, cbinfo);
 }
 
diff --git a/nan_implementation_12_inl.h b/nan_implementation_12_inl.h
index 255293ac..79731c76 100644
--- a/nan_implementation_12_inl.h
+++ b/nan_implementation_12_inl.h
@@ -14,6 +14,22 @@
 
 namespace imp {
 
+// Recent V8 versions (currently Chromium/Electron's V8 snapshot; not yet in
+// any released Node) gained an ExternalPointerTypeTag parameter on
+// v8::External::New().  Detect that API via the V8_EXTERNAL_POINTER_TAG_COUNT
+// macro (defined in <v8-internal.h> alongside the new signature) rather than
+// a V8_MAJOR_VERSION cutoff, since Node and Chromium ship divergent V8
+// snapshots under the same major version.  Externals created via this helper
+// are read back through imp::GetExternalPointer in nan_callbacks_12_inl.h,
+// which uses the matching kExternalPointerTypeTagDefault tag.
+inline v8::Local<v8::External> NewExternal(v8::Isolate* isolate, void* value) {
+#ifdef V8_EXTERNAL_POINTER_TAG_COUNT
+  return v8::External::New(isolate, value, v8::kExternalPointerTypeTagDefault);
+#else
+  return v8::External::New(isolate, value);
+#endif
+}
+
 //=== Array ====================================================================
 
 Factory<v8::Array>::return_t
@@ -76,7 +92,7 @@ Factory<v8::Date>::New(double value) {
 
 Factory<v8::External>::return_t
 Factory<v8::External>::New(void * value) {
-  return v8::External::New(v8::Isolate::GetCurrent(), value);
+  return imp::NewExternal(v8::Isolate::GetCurrent(), value);
 }
 
 //=== Function =================================================================
@@ -92,7 +108,7 @@ Factory<v8::Function>::New( FunctionCallback callback
 
   obj->SetInternalField(
       imp::kFunctionIndex
-    , v8::External::New(isolate, reinterpret_cast<void *>(callback)));
+    , imp::NewExternal(isolate, reinterpret_cast<void *>(callback)));
 
   v8::Local<v8::Value> val = v8::Local<v8::Value>::New(isolate, data);
 
@@ -128,7 +144,7 @@ Factory<v8::FunctionTemplate>::New( FunctionCallback callback
 
     obj->SetInternalField(
         imp::kFunctionIndex
-      , v8::External::New(isolate, reinterpret_cast<void *>(callback)));
+      , imp::NewExternal(isolate, reinterpret_cast<void *>(callback)));
     v8::Local<v8::Value> val = v8::Local<v8::Value>::New(isolate, data);
 
     if (!val.IsEmpty()) {
diff --git a/test/cpp/nannew.cpp b/test/cpp/nannew.cpp
index e36ce4f8..267b6b21 100644
--- a/test/cpp/nannew.cpp
+++ b/test/cpp/nannew.cpp
@@ -136,7 +136,11 @@ NAN_METHOD(testExternal) {
 
   t.plan(2);
 
+#ifdef V8_EXTERNAL_POINTER_TAG_COUNT
+  t.ok(_(New<External>(&ttt)->Value(v8::kExternalPointerTypeTagDefault) == &ttt));
+#else
   t.ok(_(New<External>(&ttt)->Value() == &ttt));
+#endif
   t.ok(_( assertType<External>(New<External>(&ttt))));
 
   info.GetReturnValue().SetUndefined();
diff --git a/test/cpp/news.cpp b/test/cpp/news.cpp
index 3597f0fc..c966af37 100644
--- a/test/cpp/news.cpp
+++ b/test/cpp/news.cpp
@@ -93,7 +93,12 @@ NAN_METHOD(NewBooleanObject) {
 
 NAN_METHOD(NewExternal) {
   v8::Local<v8::External> ext = New<v8::External>(&magic);
+#ifdef V8_EXTERNAL_POINTER_TAG_COUNT
+  assert(*static_cast<int *>(
+      ext->Value(v8::kExternalPointerTypeTagDefault)) == 1337);
+#else
   assert(*static_cast<int *>(ext->Value()) == 1337);
+#endif
   info.GetReturnValue().Set(New("passed").ToLocalChecked());
 }