diff --git a/include/xrpl/protocol/TER.h b/include/xrpl/protocol/TER.h
index aa838a736e..9fd73520d5 100644
--- a/include/xrpl/protocol/TER.h
+++ b/include/xrpl/protocol/TER.h
@@ -141,6 +141,8 @@ enum TEMcodes : TERUnderlyingType {
     temARRAY_TOO_LARGE,
     temBAD_TRANSFER_FEE,
     temINVALID_INNER_BATCH,
+
+    temBAD_WASM,
 };
 
 //------------------------------------------------------------------------------
diff --git a/src/libxrpl/protocol/TER.cpp b/src/libxrpl/protocol/TER.cpp
index 85b0d70259..35cf23d50e 100644
--- a/src/libxrpl/protocol/TER.cpp
+++ b/src/libxrpl/protocol/TER.cpp
@@ -223,6 +223,7 @@ transResults()
         MAKE_ERROR(temARRAY_TOO_LARGE,           "Malformed: Array is too large."),
         MAKE_ERROR(temBAD_TRANSFER_FEE,          "Malformed: Transfer fee is outside valid range."),
         MAKE_ERROR(temINVALID_INNER_BATCH,       "Malformed: Invalid inner batch transaction."),
+        MAKE_ERROR(temBAD_WASM,                  "Malformed: Provided WASM code is invalid."),
 
         MAKE_ERROR(terRETRY,                  "Retry transaction."),
         MAKE_ERROR(terFUNDS_SPENT,            "DEPRECATED."),
diff --git a/src/test/app/Escrow_test.cpp b/src/test/app/Escrow_test.cpp
index 197fab8aaa..23b2c29c78 100644
--- a/src/test/app/Escrow_test.cpp
+++ b/src/test/app/Escrow_test.cpp
@@ -1843,6 +1843,29 @@ struct Escrow_test : public beast::unit_test::suite
                 ter(temMALFORMED));
             env.close();
         }
+
+        {
+            // FinishFunction nonexistent host function
+            // pub fn finish() -> bool {
+            //     unsafe { host_lib::bad() >= 5 }
+            // }
+            auto const badWasmHex =
+                "0061736d010000000105016000017f02100108686f73745f6c696203626164"
+                "00000302010005030100100611027f00418080c0000b7f00418080c0000b07"
+                "2e04066d656d6f727902000666696e69736800010a5f5f646174615f656e64"
+                "03000b5f5f686561705f6261736503010a09010700100041044a0b004d0970"
+                "726f64756365727302086c616e6775616765010452757374000c70726f6365"
+                "737365642d6279010572757374631d312e38352e3120283465623136313235"
+                "3020323032352d30332d31352900490f7461726765745f6665617475726573"
+                "042b0f6d757461626c652d676c6f62616c732b087369676e2d6578742b0f72"
+                "65666572656e63652d74797065732b0a6d756c746976616c7565";
+            env(escrowCreate,
+                escrow::finish_function(badWasmHex),
+                escrow::cancel_time(env.now() + 100s),
+                fee(txnFees),
+                ter(temBAD_WASM));
+            env.close();
+        }
     }
 
     void
diff --git a/src/test/app/Wasm_test.cpp b/src/test/app/Wasm_test.cpp
index 19b7946f5b..52d3083561 100644
--- a/src/test/app/Wasm_test.cpp
+++ b/src/test/app/Wasm_test.cpp
@@ -1188,15 +1188,55 @@ struct Wasm_test : public beast::unit_test::suite
         testcase("bad wasm test");
 
         using namespace test::jtx;
-        Env env{*this};
 
+        Env env{*this};
         HostFunctions hfs;
-        auto wasmHex = "00000000";
-        auto wasmStr = boost::algorithm::unhex(std::string(wasmHex));
-        std::vector<uint8_t> wasm(wasmStr.begin(), wasmStr.end());
-        std::string funcName("mock_escrow");
-        auto re = runEscrowWasm(wasm, funcName, {}, &hfs, 15, env.journal);
-        BEAST_EXPECT(!re && re.error());
+
+        {
+            auto wasmHex = "00000000";
+            auto wasmStr = boost::algorithm::unhex(std::string(wasmHex));
+            std::vector<uint8_t> wasm(wasmStr.begin(), wasmStr.end());
+            std::string funcName("mock_escrow");
+
+            auto re = runEscrowWasm(wasm, funcName, {}, &hfs, 15, env.journal);
+            BEAST_EXPECT(!re);
+        }
+
+        {
+            auto wasmHex = "00112233445566778899AA";
+            auto wasmStr = boost::algorithm::unhex(std::string(wasmHex));
+            std::vector<uint8_t> wasm(wasmStr.begin(), wasmStr.end());
+            std::string funcName("mock_escrow");
+
+            auto const re =
+                preflightEscrowWasm(wasm, funcName, {}, &hfs, env.journal);
+            BEAST_EXPECT(!isTesSuccess(re));
+        }
+
+        {
+            // FinishFunction wrong function name
+            // pub fn bad() -> bool {
+            //     unsafe { host_lib::getLedgerSqn() >= 5 }
+            // }
+            auto const badWasmHex =
+                "0061736d010000000105016000017f02190108686f73745f6c69620c6765"
+                "744c656467657253716e00000302010005030100100611027f00418080c0"
+                "000b7f00418080c0000b072b04066d656d6f727902000362616400010a5f"
+                "5f646174615f656e6403000b5f5f686561705f6261736503010a09010700"
+                "100041044a0b004d0970726f64756365727302086c616e67756167650104"
+                "52757374000c70726f6365737365642d6279010572757374631d312e3835"
+                "2e31202834656231363132353020323032352d30332d31352900490f7461"
+                "726765745f6665617475726573042b0f6d757461626c652d676c6f62616c"
+                "732b087369676e2d6578742b0f7265666572656e63652d74797065732b0a"
+                "6d756c746976616c7565";
+            auto wasmStr = boost::algorithm::unhex(std::string(badWasmHex));
+            std::vector<uint8_t> wasm(wasmStr.begin(), wasmStr.end());
+            std::string funcName("finish");
+
+            auto const re =
+                preflightEscrowWasm(wasm, funcName, {}, &hfs, env.journal);
+            BEAST_EXPECT(!isTesSuccess(re));
+        }
     }
 
     void
@@ -1319,14 +1359,11 @@ struct Wasm_test : public beast::unit_test::suite
                 return occurrences;
             };
 
+            auto const s = sink.messages().str();
             BEAST_EXPECT(
-                countSubstr(
-                    sink.messages().str(), "WAMR Error: failed to call func") ==
-                1);
+                countSubstr(s, "WAMR Error: failed to call func") == 1);
             BEAST_EXPECT(
-                countSubstr(
-                    sink.messages().str(),
-                    "WAMR Exception: wasm operand stack overflow") == 1);
+                countSubstr(s, "Exception: wasm operand stack overflow") > 0);
         }
 
         {
diff --git a/src/xrpld/app/misc/WamrVM.cpp b/src/xrpld/app/misc/WamrVM.cpp
index cefee723f5..9ad697b1c1 100644
--- a/src/xrpld/app/misc/WamrVM.cpp
+++ b/src/xrpld/app/misc/WamrVM.cpp
@@ -133,28 +133,22 @@ print_wasm_error(std::string_view msg, wasm_trap_t* trap, beast::Journal jlog)
     auto j = jlog.error();
 #endif
 
-    j << "WAMR Error: " << msg;
+    wasm_byte_vec_t error_message WASM_EMPTY_VEC;
 
     if (trap)
-    {
-        wasm_byte_vec_t error_message;
-
         wasm_trap_message(trap, &error_message);
-        if (error_message.num_elems)
-        {
-            j <<
-#ifdef DEBUG_OUTPUT
-                "\nWAMR "
-#else
-                "WAMR "
-#endif
-              << error_message.data;
-        }
 
-        if (error_message.size)
-            wasm_byte_vec_delete(&error_message);
-        wasm_trap_delete(trap);
+    if (error_message.num_elems)
+    {
+        error_message.data[error_message.num_elems - 1] = 0;  // just in case
+        j << "WAMR Error: " << msg << ", " << error_message.data;
     }
+    else
+        j << "WAMR Error: " << msg;
+
+    if (error_message.size)
+        wasm_byte_vec_delete(&error_message);
+    wasm_trap_delete(trap);
 
 #ifdef DEBUG_OUTPUT
     j << std::endl;
@@ -185,21 +179,21 @@ InstanceWrapper::init(
     if (!mi || trap)
     {
         print_wasm_error("can't create instance", trap, j);
-        throw std::runtime_error("WAMR can't create instance");
+        throw std::runtime_error("can't create instance");
     }
     wasm_instance_exports(mi.get(), expt);
     return mi;
 }
 
 InstanceWrapper::InstanceWrapper()
-    : exports{0, nullptr, 0, 0, nullptr}
-    , mod_inst(nullptr, &wasm_instance_delete)
+    : exports_{0, nullptr, 0, 0, nullptr}
+    , instance_(nullptr, &wasm_instance_delete)
 {
 }
 
 InstanceWrapper::InstanceWrapper(InstanceWrapper&& o)
-    : exports{0, nullptr, 0, 0, nullptr}
-    , mod_inst(nullptr, &wasm_instance_delete)
+    : exports_{0, nullptr, 0, 0, nullptr}
+    , instance_(nullptr, &wasm_instance_delete)
 {
     *this = std::move(o);
 }
@@ -211,18 +205,18 @@ InstanceWrapper::InstanceWrapper(
     int64_t gas,
     wasm_extern_vec_t const& imports,
     beast::Journal j)
-    : exports WASM_EMPTY_VEC
-    , mod_inst(init(s, m, maxPages, &exports, imports, j))
-    , exec_env(wasm_instance_exec_env(mod_inst.get()))
+    : exports_ WASM_EMPTY_VEC
+    , instance_(init(s, m, maxPages, &exports_, imports, j))
+    , execEnv_(wasm_instance_exec_env(instance_.get()))
     , j_(j)
 {
-    wasm_runtime_set_instruction_count_limit(exec_env, gas);
+    wasm_runtime_set_instruction_count_limit(execEnv_, gas);
 }
 
 InstanceWrapper::~InstanceWrapper()
 {
-    if (exports.size)
-        wasm_extern_vec_delete(&exports);
+    if (exports_.size)
+        wasm_extern_vec_delete(&exports_);
 }
 
 InstanceWrapper&
@@ -231,14 +225,14 @@ InstanceWrapper::operator=(InstanceWrapper&& o)
     if (this == &o)
         return *this;
 
-    if (exports.size)
-        wasm_extern_vec_delete(&exports);
-    exports = o.exports;
-    o.exports = {0, nullptr, 0, 0, nullptr};
+    if (exports_.size)
+        wasm_extern_vec_delete(&exports_);
+    exports_ = o.exports_;
+    o.exports_ = {0, nullptr, 0, 0, nullptr};
 
-    mod_inst = std::move(o.mod_inst);
-    exec_env = o.exec_env;
-    o.exec_env = nullptr;
+    instance_ = std::move(o.instance_);
+    execEnv_ = o.execEnv_;
+    o.execEnv_ = nullptr;
 
     j_ = o.j_;
 
@@ -247,7 +241,7 @@ InstanceWrapper::operator=(InstanceWrapper&& o)
 
 InstanceWrapper::operator bool() const
 {
-    return static_cast<bool>(mod_inst);
+    return static_cast<bool>(instance_);
 }
 
 FuncInfo
@@ -258,13 +252,13 @@ InstanceWrapper::getFunc(
     wasm_func_t* f = nullptr;
     wasm_functype_t* ft = nullptr;
 
-    if (!mod_inst)
-        throw std::runtime_error("WAMR no module instance");
+    if (!instance_)
+        throw std::runtime_error("no instance");
 
     if (!export_types.num_elems)
-        throw std::runtime_error("WAMR no export");
-    if (export_types.num_elems != exports.num_elems)
-        throw std::runtime_error("WAMR invalid export");
+        throw std::runtime_error("no export");
+    if (export_types.num_elems != exports_.num_elems)
+        throw std::runtime_error("invalid export");
 
     for (unsigned i = 0; i < export_types.num_elems; ++i)
     {
@@ -276,9 +270,9 @@ InstanceWrapper::getFunc(
         {
             if (funcName == std::string_view(name->data, name->size - 1))
             {
-                auto* exn(exports.data[i]);
+                auto* exn(exports_.data[i]);
                 if (wasm_extern_kind(exn) != WASM_EXTERN_FUNC)
-                    throw std::runtime_error("WAMR invalid export");
+                    throw std::runtime_error("invalid export");
 
                 ft = wasm_externtype_as_functype(
                     const_cast<wasm_externtype_t*>(exn_type));
@@ -290,7 +284,7 @@ InstanceWrapper::getFunc(
 
     if (!f || !ft)
         throw std::runtime_error(
-            "WAMR can't find function <" + std::string(funcName) + ">");
+            "can't find function <" + std::string(funcName) + ">");
 
     return {f, ft};
 }
@@ -298,13 +292,13 @@ InstanceWrapper::getFunc(
 wmem
 InstanceWrapper::getMem() const
 {
-    if (!mod_inst)
-        throw std::runtime_error("WAMR no module instance");
+    if (!instance_)
+        throw std::runtime_error("no instance");
 
     wasm_memory_t* mem = nullptr;
-    for (unsigned i = 0; i < exports.num_elems; ++i)
+    for (unsigned i = 0; i < exports_.num_elems; ++i)
     {
-        auto* e(exports.data[i]);
+        auto* e(exports_.data[i]);
         if (wasm_extern_kind(e) == WASM_EXTERN_MEMORY)
         {
             mem = wasm_extern_as_memory(e);
@@ -313,7 +307,7 @@ InstanceWrapper::getMem() const
     }
 
     if (!mem)
-        throw std::runtime_error("WAMR no memory exported");
+        throw std::runtime_error("no memory exported");
 
     return {
         reinterpret_cast<std::uint8_t*>(wasm_memory_data(mem)),
@@ -323,7 +317,7 @@ InstanceWrapper::getMem() const
 std::int64_t
 InstanceWrapper::getGas() const
 {
-    return exec_env ? wasm_runtime_get_instruction_count_limit(exec_env) : 0;
+    return execEnv_ ? wasm_runtime_get_instruction_count_limit(execEnv_) : 0;
 }
 
 //////////////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -339,22 +333,20 @@ ModuleWrapper::init(wasm_store_t* s, Bytes const& wasmBin, beast::Journal j)
         nullptr};
     ModulePtr m = ModulePtr(wasm_module_new(s, &code), &wasm_module_delete);
     if (!m)
-    {
-        print_wasm_error("can't create module", nullptr, j);
-        throw std::runtime_error("WAMR can't create module");
-    }
+        throw std::runtime_error("can't create module");
+
     return m;
 }
 
 ModuleWrapper::ModuleWrapper()
-    : module(nullptr, &wasm_module_delete)
-    , export_types{0, nullptr, 0, 0, nullptr}
+    : module_(nullptr, &wasm_module_delete)
+    , exportTypes_{0, nullptr, 0, 0, nullptr}
 {
 }
 
 ModuleWrapper::ModuleWrapper(ModuleWrapper&& o)
-    : module(nullptr, &wasm_module_delete)
-    , export_types{0, nullptr, 0, 0, nullptr}
+    : module_(nullptr, &wasm_module_delete)
+    , exportTypes_{0, nullptr, 0, 0, nullptr}
 {
     *this = std::move(o);
 }
@@ -367,11 +359,11 @@ ModuleWrapper::ModuleWrapper(
     int64_t gas,
     std::vector<WasmImportFunc> const& imports,
     beast::Journal j)
-    : module(init(s, wasmBin, j))
-    , export_types{0, nullptr, 0, 0, nullptr}
+    : module_(init(s, wasmBin, j))
+    , exportTypes_{0, nullptr, 0, 0, nullptr}
     , j_(j)
 {
-    wasm_module_exports(module.get(), &export_types);
+    wasm_module_exports(module_.get(), &exportTypes_);
     if (instantiate)
     {
         auto wimports = buildImports(s, imports);
@@ -381,8 +373,8 @@ ModuleWrapper::ModuleWrapper(
 
 ModuleWrapper::~ModuleWrapper()
 {
-    if (export_types.size)
-        wasm_exporttype_vec_delete(&export_types);
+    if (exportTypes_.size)
+        wasm_exporttype_vec_delete(&exportTypes_);
 }
 
 ModuleWrapper&
@@ -391,12 +383,12 @@ ModuleWrapper::operator=(ModuleWrapper&& o)
     if (this == &o)
         return *this;
 
-    module = std::move(o.module);
-    mod_inst = std::move(o.mod_inst);
-    if (export_types.size)
-        wasm_exporttype_vec_delete(&export_types);
-    export_types = o.export_types;
-    o.export_types = {0, nullptr, 0, 0, nullptr};
+    module_ = std::move(o.module_);
+    instanceWrap_ = std::move(o.instanceWrap_);
+    if (exportTypes_.size)
+        wasm_exporttype_vec_delete(&exportTypes_);
+    exportTypes_ = o.exportTypes_;
+    o.exportTypes_ = {0, nullptr, 0, 0, nullptr};
     j_ = o.j_;
 
     return *this;
@@ -404,7 +396,7 @@ ModuleWrapper::operator=(ModuleWrapper&& o)
 
 ModuleWrapper::operator bool() const
 {
-    return mod_inst;
+    return instanceWrap_;
 }
 
 void
@@ -437,7 +429,7 @@ ModuleWrapper::makeImpParams(wasm_valtype_vec_t& v, WasmImportFunc const& imp)
                 v.data[i] = wasm_valtype_new_f64();
                 break;
             default:
-                throw std::runtime_error("WAMR Invalid import type");
+                throw std::runtime_error("invalid import type");
         }
     }
 }
@@ -464,7 +456,7 @@ ModuleWrapper::makeImpReturn(wasm_valtype_vec_t& v, WasmImportFunc const& imp)
                 v.data[0] = wasm_valtype_new_f64();
                 break;
             default:
-                throw std::runtime_error("WAMR Invalid return type");
+                throw std::runtime_error("invalid return type");
         }
     }
     else
@@ -477,7 +469,7 @@ ModuleWrapper::buildImports(
     std::vector<WasmImportFunc> const& imports)
 {
     wasm_importtype_vec_t importTypes = WASM_EMPTY_VEC;
-    wasm_module_imports(module.get(), &importTypes);
+    wasm_module_imports(module_.get(), &importTypes);
     std::
         unique_ptr<wasm_importtype_vec_t, decltype(&wasm_importtype_vec_delete)>
             itDeleter(&importTypes, &wasm_importtype_vec_delete);
@@ -572,19 +564,19 @@ ModuleWrapper::buildImports(
 FuncInfo
 ModuleWrapper::getFunc(std::string_view funcName) const
 {
-    return mod_inst.getFunc(funcName, export_types);
+    return instanceWrap_.getFunc(funcName, exportTypes_);
 }
 
 wmem
 ModuleWrapper::getMem() const
 {
-    return mod_inst.getMem();
+    return instanceWrap_.getMem();
 }
 
 InstanceWrapper const&
 ModuleWrapper::getInstance(int) const
 {
-    return mod_inst;
+    return instanceWrap_;
 }
 
 int
@@ -594,7 +586,7 @@ ModuleWrapper::addInstance(
     int64_t gas,
     wasm_extern_vec_t const& imports)
 {
-    mod_inst = {s, module.get(), maxPages, gas, imports, j_};
+    instanceWrap_ = {s, module_.get(), maxPages, gas, imports, j_};
     return 0;
 }
 
@@ -611,7 +603,7 @@ ModuleWrapper::addInstance(
 std::int64_t
 ModuleWrapper::getGas()
 {
-    return mod_inst.getGas();
+    return instanceWrap_.getGas();
 }
 
 //////////////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -625,8 +617,8 @@ ModuleWrapper::getGas()
 // }
 
 WamrEngine::WamrEngine()
-    : engine(wasm_engine_new(), &wasm_engine_delete)
-    , store(nullptr, &wasm_store_delete)
+    : engine_(wasm_engine_new(), &wasm_engine_delete)
+    , store_(nullptr, &wasm_store_delete)
 {
     wasm_runtime_set_default_running_mode(Mode_Interp);
     wasm_runtime_set_log_level(WASM_LOG_LEVEL_FATAL);
@@ -640,19 +632,16 @@ WamrEngine::addModule(
     int64_t gas,
     std::vector<WasmImportFunc> const& imports)
 {
-    module.reset();
-    store.reset();  // to free the memory before creating new store
-    store = {wasm_store_new(engine.get()), &wasm_store_delete};
-    module = std::make_unique<ModuleWrapper>(
-        store.get(), wasmCode, instantiate, defMaxPages, gas, imports, j_);
+    moduleWrap_.reset();
+    store_.reset();  // to free the memory before creating new store
+    store_ = {wasm_store_new(engine_.get()), &wasm_store_delete};
+    moduleWrap_ = std::make_unique<ModuleWrapper>(
+        store_.get(), wasmCode, instantiate, defMaxPages_, gas, imports, j_);
 
-    if (!module)
-    {
-        print_wasm_error("can't create module wrapper", nullptr, j_);
-        throw std::runtime_error("WAMR can't create module wrapper");
-    }
+    if (!moduleWrap_)
+        throw std::runtime_error("can't create module wrapper");
 
-    return module ? 0 : -1;
+    return moduleWrap_ ? 0 : -1;
 }
 
 // int
@@ -664,7 +653,7 @@ WamrEngine::addModule(
 FuncInfo
 WamrEngine::getFunc(std::string_view funcName)
 {
-    return module->getFunc(funcName);
+    return moduleWrap_->getFunc(funcName);
 }
 
 std::vector<wasm_val_t>
@@ -699,6 +688,8 @@ WamrEngine::convertParams(std::vector<WasmParam> const& params)
             }
             break;
             default:
+                throw std::runtime_error(
+                    "unknown parameter type: " + std::to_string(p.type));
                 break;
         }
     }
@@ -706,6 +697,25 @@ WamrEngine::convertParams(std::vector<WasmParam> const& params)
     return v;
 }
 
+int
+WamrEngine::compareParamTypes(
+    wasm_valtype_vec_t const* ftp,
+    std::vector<wasm_val_t> const& p)
+{
+    if (ftp->num_elems != p.size())
+        return std::min(ftp->num_elems, p.size());
+
+    for (unsigned i = 0; i < ftp->num_elems; ++i)
+    {
+        auto const t1 = wasm_valtype_kind(ftp->data[i]);
+        auto const t2 = p[i].kind;
+        if (t1 != t2)
+            return i;
+    }
+
+    return -1;
+}
+
 void
 WamrEngine::add_param(std::vector<wasm_val_t>& in, int32_t p)
 {
@@ -761,13 +771,6 @@ WamrEngine::call(FuncInfo const& f, std::vector<wasm_val_t>& in)
     // if (NR)  {   wasm_val_vec_new_uninitialized(&ret, NR);    //
     // wasm_val_vec_new(&ret, NR, &rs[0]);    // ret = WASM_ARRAY_VEC(rs);    }
 
-    auto const* ftp = wasm_functype_params(f.second);
-    if (ftp->num_elems != in.size())
-    {
-        print_wasm_error("invalid num of params to call func", nullptr, j_);
-        return ret;
-    }
-
     wasm_val_vec_t const inv = in.empty()
         ? wasm_val_vec_t WASM_EMPTY_VEC
         : wasm_val_vec_t{
@@ -877,7 +880,7 @@ WamrEngine::run(
     }
     catch (...)
     {
-        print_wasm_error(std::string("unknown exception"), nullptr, j_);
+        print_wasm_error(std::string("exception: unknown"), nullptr, j_);
     }
     return Unexpected<TER>(tecFAILED_PROCESSING);
 }
@@ -891,15 +894,8 @@ WamrEngine::runHlp(
     HostFunctions* hfs,
     int64_t gas)
 {
-    // #ifdef DEBUG_OUTPUT
-    //     auto& j = std::cerr;
-    // #else
-    //     auto j = j_.debug();
-    // #endif
-
     // currently only 1 module support, possible parallel UT run
-    static std::mutex m;
-    std::lock_guard<decltype(m)> lg(m);
+    std::lock_guard<decltype(m_)> lg(m_);
 
     // Create and instantiate the module.
     if (!wasmCode.empty())
@@ -907,65 +903,130 @@ WamrEngine::runHlp(
         [[maybe_unused]] int const m = addModule(wasmCode, true, gas, imports);
     }
 
-    if (!module || !module->mod_inst)
-    {
-        print_wasm_error("no instance to run", nullptr, j_);
-        return Unexpected<TER>(tecFAILED_PROCESSING);
-    }
+    if (!moduleWrap_ || !moduleWrap_->instanceWrap_)
+        throw std::runtime_error("no instance");
 
     if (hfs)
         hfs->setRT(&getRT());
 
     // Call main
-    auto f = getFunc(!funcName.empty() ? funcName : "_start");
+    auto const f = getFunc(!funcName.empty() ? funcName : "_start");
+    auto const* ftp = wasm_functype_params(f.second);
+
+    // not const because passed directly to wamr function (which accept non
+    // const)
     auto p = convertParams(params);
-    auto res = call<1>(f, p);
+
+    if (int const comp = compareParamTypes(ftp, p); comp >= 0)
+        throw std::runtime_error(
+            "invalid parameter type #" + std::to_string(comp));
+
+    auto const res = call<1>(f, p);
 
     if (res.f)
-    {
-        return Unexpected<TER>(tecFAILED_PROCESSING);
-    }
+        throw std::runtime_error("<" + std::string(funcName) + "> failed");
     else if (!res.r.num_elems)
-    {
-        print_wasm_error(
-            "<" + std::string(funcName) + "> return nothing", nullptr, j_);
-        return Unexpected<TER>(tecFAILED_PROCESSING);
-    }
+        throw std::runtime_error(
+            "<" + std::string(funcName) + "> return nothing");
 
     assert(res.r.data[0].kind == WASM_I32);
     if (gas == -1)
         gas = std::numeric_limits<decltype(gas)>::max();
-    WasmResult<int32_t> const ret{res.r.data[0].of.i32, gas - module->getGas()};
+    WasmResult<int32_t> const ret{
+        res.r.data[0].of.i32, gas - moduleWrap_->getGas()};
 
+    // #ifdef DEBUG_OUTPUT
+    //     auto& j = std::cerr;
+    // #else
+    //     auto j = j_.debug();
+    // #endif
     // j << "WAMR Res: " << ret.result << " cost: " << ret.cost << std::endl;
+
     return ret;
 }
 
+NotTEC
+WamrEngine::check(
+    Bytes const& wasmCode,
+    std::string_view funcName,
+    std::vector<WasmParam> const& params,
+    std::vector<WasmImportFunc> const& imports,
+    beast::Journal j)
+{
+    j_ = j;
+    wasm_runtime_set_log_level(
+        std::min(getLogLevel(j_.sink().threshold()), WASM_LOG_LEVEL_ERROR));
+    try
+    {
+        return checkHlp(wasmCode, funcName, params, imports);
+    }
+    catch (std::exception const& e)
+    {
+        print_wasm_error(std::string("exception: ") + e.what(), nullptr, j_);
+    }
+    catch (...)
+    {
+        print_wasm_error(std::string("exception: unknown"), nullptr, j_);
+    }
+
+    return temBAD_WASM;
+}
+
+NotTEC
+WamrEngine::checkHlp(
+    Bytes const& wasmCode,
+    std::string_view funcName,
+    std::vector<WasmParam> const& params,
+    std::vector<WasmImportFunc> const& imports)
+{
+    // currently only 1 module support, possible parallel UT run
+    std::lock_guard<decltype(m_)> lg(m_);
+
+    // Create and instantiate the module.
+    if (wasmCode.empty())
+        throw std::runtime_error("empty nodule");
+
+    int const m = addModule(wasmCode, true, -1, imports);
+    if ((m < 0) || !moduleWrap_ || !moduleWrap_->instanceWrap_)
+        throw std::runtime_error("no instance");
+
+    // Looking for a func and compare parameter types
+    auto const f = getFunc(!funcName.empty() ? funcName : "_start");
+    auto const* ftp = wasm_functype_params(f.second);
+    auto const p = convertParams(params);
+
+    if (int const comp = compareParamTypes(ftp, p); comp >= 0)
+        throw std::runtime_error(
+            "invalid parameter type #" + std::to_string(comp));
+
+    return tesSUCCESS;
+}
+
 std::int32_t
 WamrEngine::initMaxPages(std::int32_t def)
 {
-    defMaxPages = def;
+    defMaxPages_ = def;
     return def;
 }
 
 std::int64_t
 WamrEngine::getGas()
 {
-    return module ? module->getGas() : 0;
+    return moduleWrap_ ? moduleWrap_->getGas() : 0;
 }
 
 wmem
 WamrEngine::getMem() const
 {
-    return module ? module->getMem() : wmem();
+    return moduleWrap_ ? moduleWrap_->getMem() : wmem();
 }
 
 InstanceWrapper const&
 WamrEngine::getRT(int m, int i)
 {
-    if (!module)
-        throw std::runtime_error("WAMR no module");
-    return module->getInstance(i);
+    if (!moduleWrap_)
+        throw std::runtime_error("no module");
+    return moduleWrap_->getInstance(i);
 }
 
 int32_t
@@ -976,7 +1037,7 @@ WamrEngine::allocate(int32_t sz)
     if (res.f || !res.r.num_elems || (res.r.data[0].kind != WASM_I32) ||
         !res.r.data[0].of.i32)
         throw std::runtime_error(
-            "WAMR can't allocate memory, " + std::to_string(sz) + " bytes");
+            "can't allocate memory, " + std::to_string(sz) + " bytes");
     return res.r.data[0].of.i32;
 }
 
@@ -988,7 +1049,7 @@ WamrEngine::newTrap(std::string_view txt)
     if (!txt.empty())
         wasm_name_new(&msg, txt.size(), txt.data());
 
-    return wasm_trap_new(store.get(), &msg);
+    return wasm_trap_new(store_.get(), &msg);
 }
 
 beast::Journal
diff --git a/src/xrpld/app/misc/WamrVM.h b/src/xrpld/app/misc/WamrVM.h
index 57c65504e1..3be35c673e 100644
--- a/src/xrpld/app/misc/WamrVM.h
+++ b/src/xrpld/app/misc/WamrVM.h
@@ -28,17 +28,20 @@ namespace ripple {
 struct WamrResult
 {
     wasm_val_vec_t r;
-    bool f;
+    bool f;  // failure flag
+
     WamrResult(unsigned N = 0) : r{0, nullptr, 0, 0, nullptr}, f(false)
     {
         if (N)
             wasm_val_vec_new_uninitialized(&r, N);
     }
+
     ~WamrResult()
     {
         if (r.size)
             wasm_val_vec_delete(&r);
     }
+
     WamrResult(WamrResult const&) = delete;
     WamrResult&
     operator=(WamrResult const&) = delete;
@@ -47,6 +50,7 @@ struct WamrResult
     {
         *this = std::move(o);
     }
+
     WamrResult&
     operator=(WamrResult&& o)
     {
@@ -67,9 +71,9 @@ using FuncInfo = std::pair<wasm_func_t const*, wasm_functype_t const*>;
 
 struct InstanceWrapper
 {
-    wasm_extern_vec_t exports;
-    InstancePtr mod_inst;
-    wasm_exec_env_t exec_env = nullptr;
+    wasm_extern_vec_t exports_;
+    InstancePtr instance_;
+    wasm_exec_env_t execEnv_ = nullptr;
     beast::Journal j_ = beast::Journal(beast::Journal::getNullSink());
 
 private:
@@ -116,9 +120,9 @@ public:
 
 struct ModuleWrapper
 {
-    ModulePtr module;
-    InstanceWrapper mod_inst;
-    wasm_exporttype_vec_t export_types;
+    ModulePtr module_;
+    InstanceWrapper instanceWrap_;
+    wasm_exporttype_vec_t exportTypes_;
     beast::Journal j_ = beast::Journal(beast::Journal::getNullSink());
 
 private:
@@ -171,12 +175,14 @@ private:
 
 class WamrEngine
 {
-    std::unique_ptr<wasm_engine_t, decltype(&wasm_engine_delete)> engine;
-    std::unique_ptr<wasm_store_t, decltype(&wasm_store_delete)> store;
-    std::unique_ptr<ModuleWrapper> module;
-    std::int32_t defMaxPages = -1;
+    std::unique_ptr<wasm_engine_t, decltype(&wasm_engine_delete)> engine_;
+    std::unique_ptr<wasm_store_t, decltype(&wasm_store_delete)> store_;
+    std::unique_ptr<ModuleWrapper> moduleWrap_;
+    std::int32_t defMaxPages_ = -1;
     beast::Journal j_ = beast::Journal(beast::Journal::getNullSink());
 
+    std::mutex m_;  // 1 instance mutex
+
 public:
     WamrEngine();
     ~WamrEngine() = default;
@@ -190,6 +196,14 @@ public:
         int64_t gas,
         beast::Journal j);
 
+    NotTEC
+    check(
+        Bytes const& wasmCode,
+        std::string_view funcName,
+        std::vector<WasmParam> const& params,
+        std::vector<WasmImportFunc> const& imports,
+        beast::Journal j);
+
     std::int32_t
     initMaxPages(std::int32_t def);
 
@@ -222,6 +236,13 @@ private:
         HostFunctions* hfs,
         int64_t gas);
 
+    NotTEC
+    checkHlp(
+        Bytes const& wasmCode,
+        std::string_view funcName,
+        std::vector<WasmParam> const& params,
+        std::vector<WasmImportFunc> const& imports);
+
     int
     addModule(
         Bytes const& wasmCode,
@@ -247,9 +268,14 @@ private:
     std::vector<wasm_val_t>
     convertParams(std::vector<WasmParam> const& params);
 
-    void
+    static int
+    compareParamTypes(
+        wasm_valtype_vec_t const* ftp,
+        std::vector<wasm_val_t> const& p);
+
+    static void
     add_param(std::vector<wasm_val_t>& in, int32_t p);
-    void
+    static void
     add_param(std::vector<wasm_val_t>& in, int64_t p);
 
     template <int NR, class... Types>
diff --git a/src/xrpld/app/misc/WasmVM.cpp b/src/xrpld/app/misc/WasmVM.cpp
index dbfcfe549c..b21007b9d8 100644
--- a/src/xrpld/app/misc/WasmVM.cpp
+++ b/src/xrpld/app/misc/WasmVM.cpp
@@ -29,19 +29,9 @@
 
 namespace ripple {
 
-Expected<EscrowResult, TER>
-runEscrowWasm(
-    Bytes const& wasmCode,
-    std::string_view funcName,
-    std::vector<WasmParam> const& params,
-    HostFunctions* hfs,
-    int64_t gasLimit,
-    beast::Journal j)
+static std::vector<WasmImportFunc>
+createImports(HostFunctions* hfs)
 {
-    //  create VM and set cost limit
-    auto& vm = WasmEngine::instance();
-    vm.initMaxPages(MAX_PAGES);
-
     std::vector<WasmImportFunc> imports;
 
     if (hfs)
@@ -107,11 +97,27 @@ runEscrowWasm(
         WASM_IMPORT_FUNC2(imports, traceNum, "trace_num", hfs);
     }
 
-    auto ret = vm.run(
+    return imports;
+}
+
+Expected<EscrowResult, TER>
+runEscrowWasm(
+    Bytes const& wasmCode,
+    std::string_view funcName,
+    std::vector<WasmParam> const& params,
+    HostFunctions* hfs,
+    int64_t gasLimit,
+    beast::Journal j)
+{
+    //  create VM and set cost limit
+    auto& vm = WasmEngine::instance();
+    vm.initMaxPages(MAX_PAGES);
+
+    auto const ret = vm.run(
         wasmCode,
         funcName,
         params,
-        imports,
+        createImports(hfs),
         hfs,
         gasLimit,
         hfs ? hfs->getJournal() : j);
@@ -130,6 +136,28 @@ runEscrowWasm(
     return EscrowResult{ret->result > 0, ret->cost};
 }
 
+NotTEC
+preflightEscrowWasm(
+    Bytes const& wasmCode,
+    std::string_view funcName,
+    std::vector<WasmParam> const& params,
+    HostFunctions* hfs,
+    beast::Journal j)
+{
+    //  create VM and set cost limit
+    auto& vm = WasmEngine::instance();
+    vm.initMaxPages(MAX_PAGES);
+
+    auto const ret = vm.check(
+        wasmCode,
+        funcName,
+        params,
+        createImports(hfs),
+        hfs ? hfs->getJournal() : j);
+
+    return ret;
+}
+
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
 WasmEngine::WasmEngine() : impl(std::make_unique<WamrEngine>())
@@ -156,6 +184,17 @@ WasmEngine::run(
     return impl->run(wasmCode, funcName, params, imports, hfs, gasLimit, j);
 }
 
+NotTEC
+WasmEngine::check(
+    Bytes const& wasmCode,
+    std::string_view funcName,
+    std::vector<WasmParam> const& params,
+    std::vector<WasmImportFunc> const& imports,
+    beast::Journal j)
+{
+    return impl->check(wasmCode, funcName, params, imports, j);
+}
+
 std::int32_t
 WasmEngine::initMaxPages(std::int32_t def)
 {
diff --git a/src/xrpld/app/misc/WasmVM.h b/src/xrpld/app/misc/WasmVM.h
index b12d7ecc7e..7c68a18696 100644
--- a/src/xrpld/app/misc/WasmVM.h
+++ b/src/xrpld/app/misc/WasmVM.h
@@ -65,6 +65,14 @@ public:
         int64_t gasLimit = -1,
         beast::Journal j = beast::Journal{beast::Journal::getNullSink()});
 
+    NotTEC
+    check(
+        Bytes const& wasmCode,
+        std::string_view funcName,
+        std::vector<WasmParam> const& params = {},
+        std::vector<WasmImportFunc> const& imports = {},
+        beast::Journal j = beast::Journal{beast::Journal::getNullSink()});
+
     std::int32_t
     initMaxPages(std::int32_t def);
 
@@ -87,4 +95,12 @@ runEscrowWasm(
     int64_t gasLimit = -1,
     beast::Journal j = beast::Journal(beast::Journal::getNullSink()));
 
+NotTEC
+preflightEscrowWasm(
+    Bytes const& wasmCode,
+    std::string_view funcName,
+    std::vector<WasmParam> const& params = {},
+    HostFunctions* hfs = nullptr,
+    beast::Journal j = beast::Journal(beast::Journal::getNullSink()));
+
 }  // namespace ripple
diff --git a/src/xrpld/app/tx/detail/Escrow.cpp b/src/xrpld/app/tx/detail/Escrow.cpp
index 6f52d1a4f2..7639b4efa0 100644
--- a/src/xrpld/app/tx/detail/Escrow.cpp
+++ b/src/xrpld/app/tx/detail/Escrow.cpp
@@ -231,7 +231,14 @@ EscrowCreate::preflight(PreflightContext const& ctx)
                 << "EscrowCreate.FinishFunction bad size " << code.size();
             return temMALFORMED;
         }
-        // TODO: add check to ensure this is valid WASM code
+
+        HostFunctions mock;
+        auto const re = preflightEscrowWasm(code, "finish", {}, &mock);
+        if (!isTesSuccess(re))
+        {
+            JLOG(ctx.j.debug()) << "EscrowCreate.FinishFunction bad WASM";
+            return re;
+        }
     }
 
     return preflight2(ctx);