diff --git a/src/Config.cpp b/src/Config.cpp
index bffadfd8d..6973b3949 100644
--- a/src/Config.cpp
+++ b/src/Config.cpp
@@ -375,14 +375,14 @@ class ConfigInternal {
     throw FileNotFound(path);
   }
 
-  DictPtr LoadTextMarisaDictWithResourceProvider(const std::string& fileName) {
+  DictPtr LoadTextDartsDictWithResourceProvider(const std::string& fileName) {
     if (resourceProvider == nullptr) {
       throw FileNotFound(fileName);
     }
 
     const std::shared_ptr<const ResourceProvider::Resource> resource =
         resourceProvider->GetResource(fileName);
-    std::string cacheKey = "text-marisa\n" + resource->CacheKey();
+    std::string cacheKey = "text-darts\n" + resource->CacheKey();
     {
       std::lock_guard<std::mutex> lock(DictCacheMutex());
       PruneExpiredDictCache();
@@ -397,7 +397,7 @@ class ConfigInternal {
 
     TextDictPtr textDict = TextDict::NewFromBuffer(resource->Data(),
                                                    resource->Size());
-    DictPtr dict = MarisaDict::NewFromDict(*textDict.get());
+    DictPtr dict = DartsDict::NewFromDict(*textDict.get());
     {
       std::lock_guard<std::mutex> lock(DictCacheMutex());
       PruneExpiredDictCache();
@@ -481,7 +481,7 @@ class ConfigInternal {
   DictPtr LoadDictFromFile(const std::string& type,
                            const std::string& fileName) {
     if (type == "text") {
-      return LoadTextMarisaDictWithResourceProvider(fileName);
+      return LoadTextDartsDictWithResourceProvider(fileName);
     }
     if (type == "ocd") {
       if (resourceProvider != nullptr) {
diff --git a/src/tools/BUILD.bazel b/src/tools/BUILD.bazel
index 234aab644..3e09b8e03 100644
--- a/src/tools/BUILD.bazel
+++ b/src/tools/BUILD.bazel
@@ -60,3 +60,13 @@ cc_binary(
         "//src:phrase_extract_lib",
     ],
 )
+
+cc_binary(
+    name = "speed_benchmark",
+    srcs = ["SpeedBenchmark.cpp"],
+    deps = [
+        "//src:resource_provider_lib",
+        "//src:simple_converter_lib",
+        "//src:utf8_util_lib",
+    ],
+)
diff --git a/src/tools/SpeedBenchmark.cpp b/src/tools/SpeedBenchmark.cpp
new file mode 100644
index 000000000..66d95a419
--- /dev/null
+++ b/src/tools/SpeedBenchmark.cpp
@@ -0,0 +1,154 @@
+/*
+ * Open Chinese Convert
+ *
+ * Copyright 2010-2026 Carbo Kuo and contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Throughput benchmark for SimpleConverter.
+//
+// Usage:
+//   speed_benchmark [--resource-zip <zip>] <config> <corpus_file> [reps]
+//                   [-- <search_path>...]
+//
+// Examples:
+//   speed_benchmark s2t.json /tmp/corpus.txt 30 -- data/config bazel-bin/data/dictionary
+//   speed_benchmark --resource-zip opencc-resources-ocd2.zip s2t.json /tmp/corpus.txt 30
+//
+// Prints:
+//   - init time (ms)
+//   - corpus size
+//   - per-iteration time (ms) and throughput (M chars/s, ns/char)
+
+#include <chrono>
+#include <fstream>
+#include <iostream>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "src/ResourceProvider.hpp"
+#include "src/SimpleConverter.hpp"
+#include "src/UTF8Util.hpp"
+
+using Clock = std::chrono::steady_clock;
+
+static double ElapsedMs(Clock::time_point a, Clock::time_point b) {
+  return std::chrono::duration<double, std::milli>(b - a).count();
+}
+
+static std::string ReadFile(const std::string& path) {
+  std::ifstream f(path, std::ios::binary);
+  if (!f) {
+    throw std::runtime_error("cannot open file: " + path);
+  }
+  return std::string(std::istreambuf_iterator<char>(f), {});
+}
+
+int main(int argc, char** argv) {
+  std::string resourceZip;
+  std::vector<std::string> extraPaths;
+
+  // Collect non-positional args first
+  int argIdx = 1;
+  while (argIdx < argc && std::string(argv[argIdx]) == "--resource-zip") {
+    if (argIdx + 1 >= argc) {
+      std::cerr << "error: --resource-zip requires an argument\n";
+      return 1;
+    }
+    resourceZip = argv[argIdx + 1];
+    argIdx += 2;
+  }
+
+  if (argIdx + 1 >= argc) {
+    std::cerr << "usage: speed_benchmark [--resource-zip <zip>] <config> <corpus_file>"
+                 " [reps] [-- <search_path>...]\n";
+    return 1;
+  }
+
+  const std::string config     = argv[argIdx++];
+  const std::string corpusFile = argv[argIdx++];
+  int               reps       = 20;
+
+  for (int i = argIdx; i < argc; i++) {
+    if (std::string(argv[i]) == "--") {
+      for (int j = i + 1; j < argc; j++) {
+        extraPaths.push_back(argv[j]);
+      }
+      break;
+    }
+    reps = std::stoi(argv[i]);
+  }
+
+  const std::string corpus = ReadFile(corpusFile);
+  const size_t corpusBytes = corpus.size();
+
+  // Count Unicode code points for a fair comparison with JS benchmark.
+  size_t corpusChars = 0;
+  for (const char* p = corpus.data(), *end = p + corpus.size(); p < end;) {
+    const size_t n = opencc::UTF8Util::NextCharLength(p);
+    p += (n > 0 && p + n <= end) ? n : 1;
+    ++corpusChars;
+  }
+
+  // ── init ──────────────────────────────────────────────────────────────────
+  auto t0 = Clock::now();
+  std::unique_ptr<opencc::SimpleConverter> converterPtr;
+  if (!resourceZip.empty()) {
+    auto provider = std::make_shared<opencc::ZipResourceProvider>(resourceZip);
+    converterPtr = std::make_unique<opencc::SimpleConverter>(config, provider);
+  } else {
+    converterPtr = std::make_unique<opencc::SimpleConverter>(config, extraPaths);
+  }
+  auto t1 = Clock::now();
+  const double initMs = ElapsedMs(t0, t1);
+
+  opencc::SimpleConverter& converter = *converterPtr;
+
+  // ── warmup ────────────────────────────────────────────────────────────────
+  volatile size_t sink = 0;
+  sink += converter.Convert(corpus).size();
+
+  // ── timed loop ────────────────────────────────────────────────────────────
+  auto t2 = Clock::now();
+  for (int i = 0; i < reps; i++) {
+    sink += converter.Convert(corpus).size();
+  }
+  auto t3 = Clock::now();
+
+  (void)sink;
+
+  const double totalMs  = ElapsedMs(t2, t3);
+  const double perIterMs = totalMs / reps;
+  const double totalChars = static_cast<double>(corpusChars) * reps;
+  const double throughputMCharsPerSec = totalChars / totalMs / 1000.0;
+  const double nsPerChar = totalMs * 1e6 / totalChars;
+
+  std::string zipLabel = resourceZip.empty() ? "(filesystem)" : resourceZip;
+  // Strip directory prefix for brevity
+  const size_t slash = zipLabel.rfind('/');
+  if (slash != std::string::npos) zipLabel = zipLabel.substr(slash + 1);
+
+  std::cout << "C++ SimpleConverter  config=" << config
+            << "  zip=" << zipLabel << "\n";
+  std::cout << "  init:         " << initMs       << " ms\n";
+  std::cout << "  corpus:       " << corpusChars  << " chars  "
+                                  << corpusBytes  << " bytes\n";
+  std::cout << "  reps:         " << reps         << "\n";
+  std::cout << "  per iter:     " << perIterMs    << " ms\n";
+  std::cout << "  throughput:   " << throughputMCharsPerSec << " M chars/s\n";
+  std::cout << "  ns/char:      " << nsPerChar    << "\n";
+
+  return 0;
+}