diff --git a/libdeno/api.cc b/libdeno/api.cc
index c059bb534a..eac6bdb619 100644
--- a/libdeno/api.cc
+++ b/libdeno/api.cc
@@ -16,8 +16,7 @@ extern "C" {
 Deno* deno_new(deno_buf snapshot, deno_buf shared, deno_recv_cb cb) {
   deno::DenoIsolate* d = new deno::DenoIsolate(snapshot, cb, shared);
   v8::Isolate::CreateParams params;
-  params.array_buffer_allocator =
-      v8::ArrayBuffer::Allocator::NewDefaultAllocator();
+  params.array_buffer_allocator = d->array_buffer_allocator_;
   params.external_references = deno::external_references;
 
   if (snapshot.data_ptr) {
@@ -55,8 +54,9 @@ Deno* deno_new_snapshotter(deno_buf shared, deno_recv_cb cb,
   auto* d = new deno::DenoIsolate(deno::empty_buf, cb, shared);
   d->snapshot_creator_ = creator;
   d->AddIsolate(isolate);
-  v8::Isolate::Scope isolate_scope(isolate);
   {
+    v8::Locker locker(isolate);
+    v8::Isolate::Scope isolate_scope(isolate);
     v8::HandleScope handle_scope(isolate);
     auto context = v8::Context::New(isolate);
     creator->SetDefaultContext(context,
@@ -186,7 +186,6 @@ void deno_check_promise_errors(Deno* d_) {
 
 void deno_delete(Deno* d_) {
   deno::DenoIsolate* d = reinterpret_cast<deno::DenoIsolate*>(d_);
-  d->isolate_->Dispose();
   delete d;
 }
 
diff --git a/libdeno/deno.h b/libdeno/deno.h
index 96d1298c14..4941709a99 100644
--- a/libdeno/deno.h
+++ b/libdeno/deno.h
@@ -34,6 +34,8 @@ Deno* deno_new(deno_buf snapshot, deno_buf shared, deno_recv_cb cb);
 Deno* deno_new_snapshotter(deno_buf shared, deno_recv_cb cb,
                            const char* js_filename, const char* js_source,
                            const char* source_map);
+// Generate a snapshot. The resulting buf can be used with deno_new.
+// The caller must free the returned data by calling delete[] buf.data_ptr.
 deno_buf deno_get_snapshot(Deno* d);
 
 void deno_delete(Deno* d);
diff --git a/libdeno/internal.h b/libdeno/internal.h
index a996a00086..0113946d54 100644
--- a/libdeno/internal.h
+++ b/libdeno/internal.h
@@ -23,15 +23,26 @@ class DenoIsolate {
         cb_(cb),
         next_req_id_(0),
         user_data_(nullptr) {
+    array_buffer_allocator_ = v8::ArrayBuffer::Allocator::NewDefaultAllocator();
     if (snapshot.data_ptr) {
       snapshot_.data = reinterpret_cast<const char*>(snapshot.data_ptr);
       snapshot_.raw_size = static_cast<int>(snapshot.data_len);
     }
   }
 
+  ~DenoIsolate() {
+    if (snapshot_creator_) {
+      delete snapshot_creator_;
+    } else {
+      isolate_->Dispose();
+    }
+    delete array_buffer_allocator_;
+  }
+
   void AddIsolate(v8::Isolate* isolate);
 
   v8::Isolate* isolate_;
+  v8::ArrayBuffer::Allocator* array_buffer_allocator_;
   deno_buf shared_;
   const v8::FunctionCallbackInfo<v8::Value>* current_args_;
   v8::SnapshotCreator* snapshot_creator_;
diff --git a/libdeno/libdeno_test.cc b/libdeno/libdeno_test.cc
index 7e7cd966c3..3af51a5a98 100644
--- a/libdeno/libdeno_test.cc
+++ b/libdeno/libdeno_test.cc
@@ -14,15 +14,22 @@ TEST(LibDenoTest, InitializesCorrectlyWithoutSnapshot) {
   deno_delete(d);
 }
 
+TEST(LibDenoTest, SnapshotterInitializesCorrectly) {
+  Deno* d = deno_new_snapshotter(empty, nullptr, "a.js", "a = 1 + 2", nullptr);
+  deno_delete(d);
+}
+
 TEST(LibDenoTest, Snapshotter) {
   Deno* d1 = deno_new_snapshotter(empty, nullptr, "a.js", "a = 1 + 2", nullptr);
   deno_buf test_snapshot = deno_get_snapshot(d1);
-  // TODO(ry) deno_delete(d1);
+  deno_delete(d1);
 
   Deno* d2 = deno_new(test_snapshot, empty, nullptr);
   EXPECT_TRUE(
       deno_execute(d2, nullptr, "b.js", "if (a != 3) throw Error('x');"));
   deno_delete(d2);
+
+  delete[] test_snapshot.data_ptr;
 }
 
 TEST(LibDenoTest, CanCallFunction) {