diff --git a/crypto/CMakeLists.txt b/crypto/CMakeLists.txt
index 0871d250..827c903b 100644
--- a/crypto/CMakeLists.txt
+++ b/crypto/CMakeLists.txt
@@ -401,6 +401,7 @@ if (USE_EMSCRIPTEN)
   target_link_options(funcfiftlib PRIVATE -sALLOW_MEMORY_GROWTH=1)
   target_link_options(funcfiftlib PRIVATE -sALLOW_TABLE_GROWTH=1)
   target_link_options(funcfiftlib PRIVATE --embed-file ${CMAKE_CURRENT_SOURCE_DIR}/fift/lib@/fiftlib)
+  target_link_options(funcfiftlib PRIVATE --pre-js ${CMAKE_CURRENT_SOURCE_DIR}/funcfiftlib/funcfiftlib-prejs.js)
   target_link_options(funcfiftlib PRIVATE -fexceptions)
   target_compile_options(funcfiftlib PRIVATE -fexceptions -fno-stack-protector)
 endif()
diff --git a/crypto/funcfiftlib/funcfiftlib-prejs.js b/crypto/funcfiftlib/funcfiftlib-prejs.js
new file mode 100644
index 00000000..38326c38
--- /dev/null
+++ b/crypto/funcfiftlib/funcfiftlib-prejs.js
@@ -0,0 +1 @@
+var crypto = { getRandomValues: function(array) { for (var i = 0; i < array.length; i++) array[i] = (Math.random()*256)|0 } };
\ No newline at end of file
diff --git a/crypto/funcfiftlib/funcfiftlib.cpp b/crypto/funcfiftlib/funcfiftlib.cpp
index c8bf4fc5..a041c25d 100644
--- a/crypto/funcfiftlib/funcfiftlib.cpp
+++ b/crypto/funcfiftlib/funcfiftlib.cpp
@@ -34,29 +34,6 @@
 #include <sstream>
 #include <iomanip>
 
-std::string escape_json(const std::string &s) {
-  std::ostringstream o;
-  for (auto c = s.cbegin(); c != s.cend(); c++) {
-    switch (*c) {
-      case '"': o << "\\\""; break;
-      case '\\': o << "\\\\"; break;
-      case '\b': o << "\\b"; break;
-      case '\f': o << "\\f"; break;
-      case '\n': o << "\\n"; break;
-      case '\r': o << "\\r"; break;
-      case '\t': o << "\\t"; break;
-      default:
-        if ('\x00' <= *c && *c <= '\x1f') {
-          o << "\\u"
-            << std::hex << std::setw(4) << std::setfill('0') << static_cast<int>(*c);
-        } else {
-          o << *c;
-        }
-    }
-  }
-  return o.str();
-}
-
 td::Result<std::string> compile_internal(char *config_json) {
   TRY_RESULT(input_json, td::json_decode(td::MutableSlice(config_json)))
   auto &obj = input_json.get_object();
@@ -91,7 +68,7 @@ td::Result<std::string> compile_internal(char *config_json) {
   auto result_obj = result_json.enter_object();
   result_obj("status", "ok");
   result_obj("codeBoc", td::base64_encode(boc));
-  result_obj("fiftCode", escape_json(outs.str()));
+  result_obj("fiftCode", outs.str());
   result_obj("codeHashHex", code_cell->get_hash().to_hex());
   result_obj.leave();
 
diff --git a/emulator/CMakeLists.txt b/emulator/CMakeLists.txt
index 969f9a88..7a4b7676 100644
--- a/emulator/CMakeLists.txt
+++ b/emulator/CMakeLists.txt
@@ -48,7 +48,7 @@ if (USE_EMSCRIPTEN)
   add_executable(emulator-emscripten ${EMULATOR_EMSCRIPTEN_SOURCE})
   target_link_libraries(emulator-emscripten PUBLIC emulator)
   target_link_options(emulator-emscripten PRIVATE -sEXPORTED_RUNTIME_METHODS=_malloc,free,UTF8ToString,stringToUTF8,allocate,ALLOC_NORMAL,lengthBytesUTF8)
-  target_link_options(emulator-emscripten PRIVATE -sEXPORTED_FUNCTIONS=_emulate,_free,_run_get_method)
+  target_link_options(emulator-emscripten PRIVATE -sEXPORTED_FUNCTIONS=_emulate,_free,_run_get_method,_create_emulator,_destroy_emulator,_emulate_with_emulator)
   target_link_options(emulator-emscripten PRIVATE -sEXPORT_NAME=EmulatorModule)
   target_link_options(emulator-emscripten PRIVATE -sERROR_ON_UNDEFINED_SYMBOLS=0)
   target_link_options(emulator-emscripten PRIVATE -Oz)
@@ -57,6 +57,7 @@ if (USE_EMSCRIPTEN)
   target_link_options(emulator-emscripten PRIVATE -sMODULARIZE=1)
   target_link_options(emulator-emscripten PRIVATE -sENVIRONMENT=web)
   target_link_options(emulator-emscripten PRIVATE -sFILESYSTEM=0)
+  target_link_options(emulator-emscripten PRIVATE -sALLOW_MEMORY_GROWTH=1)
   target_link_options(emulator-emscripten PRIVATE -fexceptions)
   if (USE_EMSCRIPTEN_NO_WASM)
     target_link_options(emulator-emscripten PRIVATE -sWASM=0)
diff --git a/emulator/emulator-emscripten.cpp b/emulator/emulator-emscripten.cpp
index dbd1c0d5..e76607c6 100644
--- a/emulator/emulator-emscripten.cpp
+++ b/emulator/emulator-emscripten.cpp
@@ -124,9 +124,39 @@ td::Result<GetMethodParams> decode_get_method_params(const char* json) {
   return params;
 }
 
+class NoopLog : public td::LogInterface {
+ public:
+  NoopLog() {
+  }
+
+  void append(td::CSlice new_slice, int log_level) override {
+  }
+
+  void rotate() override {
+  }
+};
+
 extern "C" {
 
-const char *emulate(const char *config, const char* libs, int verbosity, const char* account, const char* message, const char* params) {
+void* create_emulator(const char *config, int verbosity) {
+    NoopLog logger;
+
+    td::log_interface = &logger;
+
+    SET_VERBOSITY_LEVEL(verbosity_NEVER);
+    return transaction_emulator_create(config, verbosity);
+}
+
+void destroy_emulator(void* em) {
+    NoopLog logger;
+
+    td::log_interface = &logger;
+
+    SET_VERBOSITY_LEVEL(verbosity_NEVER);
+    transaction_emulator_destroy(em);
+}
+
+const char *emulate_with_emulator(void* em, const char* libs, const char* account, const char* message, const char* params) {
     StringLog logger;
 
     td::log_interface = &logger;
@@ -138,8 +168,6 @@ const char *emulate(const char *config, const char* libs, int verbosity, const c
     }
     auto decoded_params = decoded_params_res.move_as_ok();
 
-    auto em = transaction_emulator_create(config, verbosity);
-
     bool rand_seed_set = true;
     if (decoded_params.rand_seed_hex) {
       rand_seed_set = transaction_emulator_set_rand_seed(em, decoded_params.rand_seed_hex.unwrap().c_str());
@@ -162,8 +190,6 @@ const char *emulate(const char *config, const char* libs, int verbosity, const c
       result = transaction_emulator_emulate_transaction(em, account, message);
     }
 
-    transaction_emulator_destroy(em);
-
     const char* output = nullptr;
     {
         td::JsonBuilder jb;
@@ -178,6 +204,13 @@ const char *emulate(const char *config, const char* libs, int verbosity, const c
     return output;
 }
 
+const char *emulate(const char *config, const char* libs, int verbosity, const char* account, const char* message, const char* params) {
+    auto em = transaction_emulator_create(config, verbosity);
+    auto result = emulate_with_emulator(em, libs, account, message, params);
+    transaction_emulator_destroy(em);
+    return result;
+}
+
 const char *run_get_method(const char *params, const char* stack, const char* config) {
     StringLog logger;