diff --git a/emulator/emulator-emscripten.cpp b/emulator/emulator-emscripten.cpp
index 881664bd..66e97f35 100644
--- a/emulator/emulator-emscripten.cpp
+++ b/emulator/emulator-emscripten.cpp
@@ -12,6 +12,8 @@ struct TransactionEmulationParams {
   uint64_t lt;
   td::optional<std::string> rand_seed_hex;
   bool ignore_chksig;
+  bool is_tick_tock;
+  bool is_tock;
   bool debug_enabled;
 };
 
@@ -41,6 +43,16 @@ td::Result<TransactionEmulationParams> decode_transaction_emulation_params(const
   TRY_RESULT(debug_enabled, td::get_json_object_bool_field(obj, "debug_enabled", false));
   params.debug_enabled = debug_enabled;
 
+  TRY_RESULT(is_tick_tock, td::get_json_object_bool_field(obj, "is_tick_tock", true, false));
+  params.is_tick_tock = is_tick_tock;
+
+  TRY_RESULT(is_tock, td::get_json_object_bool_field(obj, "is_tock", true, false));
+  params.is_tock = is_tock;
+
+  if (is_tock && !is_tick_tock) {
+    return td::Status::Error("Inconsistent parameters is_tick_tock=false, is_tock=true");
+  }
+
   return params;
 }
 
@@ -137,7 +149,12 @@ const char *emulate(const char *config, const char* libs, int verbosity, const c
         return strdup(R"({"fail":true,"message":"Can't set params"})");
     }
 
-    auto tx = transaction_emulator_emulate_transaction(em, account, message);
+    const char *result;
+    if (decoded_params.is_tick_tock) {
+      result = transaction_emulator_emulate_tick_tock_transaction(em, account, decoded_params.is_tock);
+    } else {
+      result = transaction_emulator_emulate_transaction(em, account, message);
+    }
 
     transaction_emulator_destroy(em);
 
@@ -145,12 +162,12 @@ const char *emulate(const char *config, const char* libs, int verbosity, const c
     {
         td::JsonBuilder jb;
         auto json_obj = jb.enter_object();
-        json_obj("output", td::JsonRaw(td::Slice(tx)));
+        json_obj("output", td::JsonRaw(td::Slice(result)));
         json_obj("logs", logger.get_string());
         json_obj.leave();
         output = strdup(jb.string_builder().as_cslice().c_str());
     }
-    free((void*) tx);
+    free((void*) result);
 
     return output;
 }
diff --git a/emulator/emulator-extern.cpp b/emulator/emulator-extern.cpp
index 31a7b649..c5717dcd 100644
--- a/emulator/emulator-extern.cpp
+++ b/emulator/emulator-extern.cpp
@@ -8,6 +8,7 @@
 #include "transaction-emulator.h"
 #include "tvm-emulator.hpp"
 #include "crypto/vm/stack.hpp"
+#include "crypto/vm/memo.h"
 
 td::Result<td::Ref<vm::Cell>> boc_b64_to_cell(const char *boc) {
   TRY_RESULT_PREFIX(boc_decoded, td::base64_decode(td::Slice(boc)), "Can't decode base64 boc: ");
@@ -42,6 +43,7 @@ const char *error_response(std::string&& error) {
   auto json_obj = jb.enter_object();
   json_obj("success", td::JsonFalse());
   json_obj("error", std::move(error));
+  json_obj("external_not_accepted", td::JsonFalse());
   json_obj.leave();
   return strdup(jb.string_builder().as_cslice().c_str());
 }
@@ -51,6 +53,7 @@ const char *external_not_accepted_response(std::string&& vm_log, int vm_exit_cod
   auto json_obj = jb.enter_object();
   json_obj("success", td::JsonFalse());
   json_obj("error", "External message not accepted by smart contract");
+  json_obj("external_not_accepted", td::JsonTrue());
   json_obj("vm_log", std::move(vm_log));
   json_obj("vm_exit_code", vm_exit_code);
   json_obj("elapsed_time", elapsed_time);
@@ -131,13 +134,16 @@ const char *transaction_emulator_emulate_transaction(void *transaction_emulator,
   }
 
   auto account = block::Account(wc, addr.bits());
-  ton::UnixTime now = (unsigned)std::time(nullptr);
+  ton::UnixTime now = emulator->get_unixtime();
+  if (!now) {
+    now = (unsigned)std::time(nullptr);
+  }
   bool is_special = wc == ton::masterchainId && emulator->get_config().is_special_smartcontract(addr);
   if (!account.unpack(vm::load_cell_slice_ref(shard_account_cell.move_as_ok()), td::Ref<vm::CellSlice>(), now, is_special)) {
     ERROR_RESPONSE(PSTRING() << "Can't unpack shard account");
   }
 
-  auto result = emulator->emulate_transaction(std::move(account), message_cell, 0, 0, block::transaction::Transaction::tr_ord);
+  auto result = emulator->emulate_transaction(std::move(account), message_cell, now, 0, block::transaction::Transaction::tr_ord);
   if (result.is_error()) {
     ERROR_RESPONSE(PSTRING() << "Emulate transaction failed: " << result.move_as_error());
   }
@@ -176,6 +182,79 @@ const char *transaction_emulator_emulate_transaction(void *transaction_emulator,
                           std::move(actions_boc_b64), emulation_success.elapsed_time);
 }
 
+const char *transaction_emulator_emulate_tick_tock_transaction(void *transaction_emulator, const char *shard_account_boc, bool is_tock) {
+  auto emulator = static_cast<emulator::TransactionEmulator *>(transaction_emulator);
+  
+  auto shard_account_cell = boc_b64_to_cell(shard_account_boc);
+  if (shard_account_cell.is_error()) {
+    ERROR_RESPONSE(PSTRING() << "Can't deserialize shard account boc: " << shard_account_cell.move_as_error());
+  }
+  auto shard_account_slice = vm::load_cell_slice(shard_account_cell.ok_ref());
+  block::gen::ShardAccount::Record shard_account;
+  if (!tlb::unpack(shard_account_slice, shard_account)) {
+    ERROR_RESPONSE(PSTRING() << "Can't unpack shard account cell");
+  }
+
+  td::Ref<vm::CellSlice> addr_slice;
+  auto account_slice = vm::load_cell_slice(shard_account.account);
+  if (block::gen::t_Account.get_tag(account_slice) == block::gen::Account::account_none) {
+    ERROR_RESPONSE(PSTRING() <<  "Can't run tick/tock transaction on account_none");
+  }
+  block::gen::Account::Record_account account_record;
+  if (!tlb::unpack(account_slice, account_record)) {
+    ERROR_RESPONSE(PSTRING() << "Can't unpack account cell");
+  }
+  addr_slice = std::move(account_record.addr);
+  ton::WorkchainId wc;
+  ton::StdSmcAddress addr;
+  if (!block::tlb::t_MsgAddressInt.extract_std_address(addr_slice, wc, addr)) {
+    ERROR_RESPONSE(PSTRING() << "Can't extract account address");
+  }
+
+  auto account = block::Account(wc, addr.bits());
+  ton::UnixTime now = emulator->get_unixtime();
+  if (!now) {
+    now = (unsigned)std::time(nullptr);
+  }
+  bool is_special = wc == ton::masterchainId && emulator->get_config().is_special_smartcontract(addr);
+  if (!account.unpack(vm::load_cell_slice_ref(shard_account_cell.move_as_ok()), td::Ref<vm::CellSlice>(), now, is_special)) {
+    ERROR_RESPONSE(PSTRING() << "Can't unpack shard account");
+  }
+
+  auto trans_type = is_tock ? block::transaction::Transaction::tr_tock : block::transaction::Transaction::tr_tick;
+  auto result = emulator->emulate_transaction(std::move(account), {}, now, 0, trans_type);
+  if (result.is_error()) {
+    ERROR_RESPONSE(PSTRING() << "Emulate transaction failed: " << result.move_as_error());
+  }
+  auto emulation_result = result.move_as_ok();
+
+  auto emulation_success = dynamic_cast<emulator::TransactionEmulator::EmulationSuccess&>(*emulation_result);
+  auto trans_boc_b64 = cell_to_boc_b64(std::move(emulation_success.transaction));
+  if (trans_boc_b64.is_error()) {
+    ERROR_RESPONSE(PSTRING() << "Can't serialize Transaction to boc " << trans_boc_b64.move_as_error());
+  }
+
+  auto new_shard_account_cell = vm::CellBuilder().store_ref(emulation_success.account.total_state)
+                               .store_bits(emulation_success.account.last_trans_hash_.as_bitslice())
+                               .store_long(emulation_success.account.last_trans_lt_).finalize();
+  auto new_shard_account_boc_b64 = cell_to_boc_b64(std::move(new_shard_account_cell));
+  if (new_shard_account_boc_b64.is_error()) {
+    ERROR_RESPONSE(PSTRING() << "Can't serialize ShardAccount to boc " << new_shard_account_boc_b64.move_as_error());
+  }
+
+  td::optional<td::string> actions_boc_b64;
+  if (emulation_success.actions.not_null()) {
+    auto actions_boc_b64_result = cell_to_boc_b64(std::move(emulation_success.actions));
+    if (actions_boc_b64_result.is_error()) {
+      ERROR_RESPONSE(PSTRING() << "Can't serialize actions list cell to boc " << actions_boc_b64_result.move_as_error());
+    }
+    actions_boc_b64 = actions_boc_b64_result.move_as_ok();
+  }
+
+  return success_response(trans_boc_b64.move_as_ok(), new_shard_account_boc_b64.move_as_ok(), std::move(emulation_success.vm_log), 
+                          std::move(actions_boc_b64), emulation_success.elapsed_time);
+}
+
 bool transaction_emulator_set_unixtime(void *transaction_emulator, uint32_t unixtime) {
   auto emulator = static_cast<emulator::TransactionEmulator *>(transaction_emulator);
 
@@ -309,16 +388,19 @@ bool tvm_emulator_set_c7(void *tvm_emulator, const char *address, uint32_t unixt
     return false;
   }
   
-  auto config_params_cell = boc_b64_to_cell(config_boc);
-  if (config_params_cell.is_error()) {
-    LOG(ERROR) << "Can't deserialize config params boc: " << config_params_cell.move_as_error();
-    return false;
-  }
-  auto global_config = std::make_shared<block::Config>(config_params_cell.move_as_ok(), td::Bits256::zero(), block::Config::needWorkchainInfo | block::Config::needSpecialSmc);
-  auto unpack_res = global_config->unpack();
-  if (unpack_res.is_error()) {
-    LOG(ERROR) << "Can't unpack config params";
-    return false;
+  std::shared_ptr<block::Config> global_config;
+  if (config_boc != nullptr) {
+    auto config_params_cell = boc_b64_to_cell(config_boc);
+    if (config_params_cell.is_error()) {
+      LOG(ERROR) << "Can't deserialize config params boc: " << config_params_cell.move_as_error();
+      return false;
+    }
+    global_config = std::make_shared<block::Config>(config_params_cell.move_as_ok(), td::Bits256::zero(), block::Config::needWorkchainInfo | block::Config::needSpecialSmc);
+    auto unpack_res = global_config->unpack();
+    if (unpack_res.is_error()) {
+      LOG(ERROR) << "Can't unpack config params";
+      return false;
+    }
   }
 
   auto rand_seed_hex_slice = td::Slice(rand_seed_hex);
@@ -365,6 +447,9 @@ const char *tvm_emulator_run_get_method(void *tvm_emulator, int method_id, const
   auto emulator = static_cast<emulator::TvmEmulator *>(tvm_emulator);
   auto result = emulator->run_get_method(method_id, stack);
   
+  vm::FakeVmStateLimits fstate(1000);  // limit recursive (de)serialization calls
+  vm::VmStateInterface::Guard guard(&fstate);
+  
   vm::CellBuilder stack_cb;
   if (!result.stack->serialize(stack_cb)) {
     ERROR_RESPONSE(PSTRING() << "Couldn't serialize stack");
diff --git a/emulator/emulator-extern.h b/emulator/emulator-extern.h
index db59a822..c2b0bf9a 100644
--- a/emulator/emulator-extern.h
+++ b/emulator/emulator-extern.h
@@ -80,8 +80,9 @@ EMULATOR_EXPORT bool transaction_emulator_set_debug_enabled(void *transaction_em
  * @return Json object with error:
  * { 
  *   "success": false, 
- *   "error": "Error description" 
- *   // and optional fields "vm_exit_code" and "vm_log" in case external message was not accepted.
+ *   "error": "Error description",
+ *   "external_not_accepted": false,
+ *   // and optional fields "vm_exit_code", "vm_log", "elapsed_time" in case external message was not accepted.
  * } 
  * Or success:
  * { 
@@ -89,11 +90,35 @@ EMULATOR_EXPORT bool transaction_emulator_set_debug_enabled(void *transaction_em
  *   "transaction": "Base64 encoded Transaction boc", 
  *   "shard_account": "Base64 encoded new ShardAccount boc", 
  *   "vm_log": "execute DUP...", 
- *   "actions": "Base64 encoded compute phase actions boc (OutList n)"
+ *   "actions": "Base64 encoded compute phase actions boc (OutList n)",
+ *   "elapsed_time": 0.02
  * }
  */
 EMULATOR_EXPORT const char *transaction_emulator_emulate_transaction(void *transaction_emulator, const char *shard_account_boc, const char *message_boc);
 
+/**
+ * @brief Emulate tick tock transaction
+ * @param transaction_emulator Pointer to TransactionEmulator object
+ * @param shard_account_boc Base64 encoded BoC serialized ShardAccount of special account
+ * @param is_tock True for tock transactions, false for tick
+ * @return Json object with error:
+ * { 
+ *   "success": false, 
+ *   "error": "Error description",
+ *   "external_not_accepted": false
+ * } 
+ * Or success:
+ * { 
+ *   "success": true, 
+ *   "transaction": "Base64 encoded Transaction boc", 
+ *   "shard_account": "Base64 encoded new ShardAccount boc", 
+ *   "vm_log": "execute DUP...", 
+ *   "actions": "Base64 encoded compute phase actions boc (OutList n)",
+ *   "elapsed_time": 0.02
+ * }
+ */
+EMULATOR_EXPORT const char *transaction_emulator_emulate_tick_tock_transaction(void *transaction_emulator, const char *shard_account_boc, bool is_tock);
+
 /**
  * @brief Destroy TransactionEmulator object
  * @param transaction_emulator Pointer to TransactionEmulator object
@@ -129,7 +154,7 @@ EMULATOR_EXPORT bool tvm_emulator_set_libraries(void *tvm_emulator, const char *
  * @param unixtime Unix timestamp
  * @param balance Smart contract balance
  * @param rand_seed_hex Random seed as hex string of length 64
- * @param config Base64 encoded BoC serialized Config dictionary (Hashmap 32 ^Cell)
+ * @param config Base64 encoded BoC serialized Config dictionary (Hashmap 32 ^Cell). Optional.
  * @return true in case of success, false in case of error 
  */
 EMULATOR_EXPORT bool tvm_emulator_set_c7(void *tvm_emulator, const char *address, uint32_t unixtime, uint64_t balance, const char *rand_seed_hex, const char *config);
diff --git a/emulator/emulator_export_list b/emulator/emulator_export_list
index 64d4ff59..950c57a0 100644
--- a/emulator/emulator_export_list
+++ b/emulator/emulator_export_list
@@ -7,6 +7,7 @@ _transaction_emulator_set_config
 _transaction_emulator_set_libs
 _transaction_emulator_set_debug_enabled
 _transaction_emulator_emulate_transaction
+_transaction_emulator_emulate_tick_tock_transaction
 _transaction_emulator_destroy
 _emulator_set_verbosity_level
 _tvm_emulator_create
diff --git a/emulator/transaction-emulator.h b/emulator/transaction-emulator.h
index 08343cb8..b26f4e8a 100644
--- a/emulator/transaction-emulator.h
+++ b/emulator/transaction-emulator.h
@@ -59,6 +59,10 @@ public:
     return config_;
   }
 
+  ton::UnixTime get_unixtime() {
+    return unixtime_;
+  }
+
   td::Result<std::unique_ptr<EmulationResult>> emulate_transaction(
       block::Account&& account, td::Ref<vm::Cell> msg_root, ton::UnixTime utime, ton::LogicalTime lt, int trans_type);
 
diff --git a/emulator/tvm-emulator.hpp b/emulator/tvm-emulator.hpp
index 0236f0ca..46e2538d 100644
--- a/emulator/tvm-emulator.hpp
+++ b/emulator/tvm-emulator.hpp
@@ -28,7 +28,9 @@ public:
     args_.set_now(unixtime);
     args_.set_balance(balance);
     args_.set_rand_seed(rand_seed);
-    args_.set_config(config);
+    if (config) {
+      args_.set_config(config);
+    }
   }
 
   void set_debug_enabled(bool debug_enabled) {