diff --git a/.github/scripts/test-c-api.sh b/.github/scripts/test-c-api.sh
index 08a1a1a2..afc66c10 100755
--- a/.github/scripts/test-c-api.sh
+++ b/.github/scripts/test-c-api.sh
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-set -e
+set -ex
 
 log() {
   # This function is from espnet
@@ -9,6 +9,7 @@ log() {
 }
 
 echo "SLID_EXE is $SLID_EXE"
+echo "SID_EXE is $SID_EXE"
 echo "PATH: $PATH"
 
 
@@ -24,3 +25,15 @@ rm sherpa-onnx-whisper-tiny.tar.bz2
 $SLID_EXE
 
 rm -rf sherpa-onnx-whisper-tiny*
+
+log "------------------------------------------------------------"
+log "Download file for speaker identification and verification   "
+log "------------------------------------------------------------"
+
+curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/speaker-recongition-models/3dspeaker_speech_campplus_sv_zh-cn_16k-common.onnx
+git clone https://github.com/csukuangfj/sr-data
+
+$SID_EXE
+
+rm -fv *.onnx
+rm -rf sr-data
diff --git a/.github/workflows/linux.yaml b/.github/workflows/linux.yaml
index 7df1761a..b1f3fa91 100644
--- a/.github/workflows/linux.yaml
+++ b/.github/workflows/linux.yaml
@@ -124,11 +124,12 @@ jobs:
           name: release-${{ matrix.build_type }}-with-shared-lib-${{ matrix.shared_lib }}-with-tts-${{ matrix.with_tts }}
           path: build/bin/*
 
-      - name: Test spoken language identification (C API)
+      - name: Test C API
         shell: bash
         run: |
           export PATH=$PWD/build/bin:$PATH
           export SLID_EXE=spoken-language-identification-c-api
+          export SID_EXE=speaker-identification-c-api
 
           .github/scripts/test-c-api.sh
 
diff --git a/.github/workflows/macos.yaml b/.github/workflows/macos.yaml
index 4152cf6c..0d098061 100644
--- a/.github/workflows/macos.yaml
+++ b/.github/workflows/macos.yaml
@@ -103,11 +103,12 @@ jobs:
           otool -L build/bin/sherpa-onnx
           otool -l build/bin/sherpa-onnx
 
-      - name: Test spoken language identification (C API)
+      - name: Test C API
         shell: bash
         run: |
           export PATH=$PWD/build/bin:$PATH
           export SLID_EXE=spoken-language-identification-c-api
+          export SID_EXE=speaker-identification-c-api
 
           .github/scripts/test-c-api.sh
 
diff --git a/.github/workflows/windows-x64.yaml b/.github/workflows/windows-x64.yaml
index bd90119c..ea7cf745 100644
--- a/.github/workflows/windows-x64.yaml
+++ b/.github/workflows/windows-x64.yaml
@@ -70,11 +70,12 @@ jobs:
 
           ls -lh ./bin/Release/sherpa-onnx.exe
 
-      - name: Test spoken language identification (C API)
+      - name: Test C API
         shell: bash
         run: |
           export PATH=$PWD/build/bin/Release:$PATH
           export SLID_EXE=spoken-language-identification-c-api.exe
+          export SID_EXE=speaker-identification-c-api.exe
 
           .github/scripts/test-c-api.sh
 
diff --git a/.gitignore b/.gitignore
index 44d78dc4..ea1d57e9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -87,3 +87,4 @@ vits-coqui-*
 vits-mms-*
 *.tar.bz2
 sherpa-onnx-paraformer-trilingual-zh-cantonese-en
+sr-data
diff --git a/c-api-examples/CMakeLists.txt b/c-api-examples/CMakeLists.txt
index fd4577f4..06956324 100644
--- a/c-api-examples/CMakeLists.txt
+++ b/c-api-examples/CMakeLists.txt
@@ -12,6 +12,9 @@ endif()
 add_executable(spoken-language-identification-c-api spoken-language-identification-c-api.c)
 target_link_libraries(spoken-language-identification-c-api sherpa-onnx-c-api)
 
+add_executable(speaker-identification-c-api speaker-identification-c-api.c)
+target_link_libraries(speaker-identification-c-api sherpa-onnx-c-api)
+
 if(SHERPA_ONNX_HAS_ALSA)
   add_subdirectory(./asr-microphone-example)
 elseif((UNIX AND NOT APPLE) OR LINUX)
diff --git a/c-api-examples/asr-microphone-example/c-api-alsa.cc b/c-api-examples/asr-microphone-example/c-api-alsa.cc
index e5d9f434..caa5d8c6 100644
--- a/c-api-examples/asr-microphone-example/c-api-alsa.cc
+++ b/c-api-examples/asr-microphone-example/c-api-alsa.cc
@@ -188,10 +188,11 @@ int32_t main(int32_t argc, char *argv[]) {
     }
   }
 
-  SherpaOnnxOnlineRecognizer *recognizer = CreateOnlineRecognizer(&config);
-  SherpaOnnxOnlineStream *stream = CreateOnlineStream(recognizer);
+  const SherpaOnnxOnlineRecognizer *recognizer =
+      CreateOnlineRecognizer(&config);
+  const SherpaOnnxOnlineStream *stream = CreateOnlineStream(recognizer);
 
-  SherpaOnnxDisplay *display = CreateDisplay(50);
+  const SherpaOnnxDisplay *display = CreateDisplay(50);
   int32_t segment_id = 0;
 
   const char *device_name = argv[context.index];
diff --git a/c-api-examples/decode-file-c-api.c b/c-api-examples/decode-file-c-api.c
index c7ea3bfb..c00275cb 100644
--- a/c-api-examples/decode-file-c-api.c
+++ b/c-api-examples/decode-file-c-api.c
@@ -162,10 +162,11 @@ int32_t main(int32_t argc, char *argv[]) {
     }
   }
 
-  SherpaOnnxOnlineRecognizer *recognizer = CreateOnlineRecognizer(&config);
-  SherpaOnnxOnlineStream *stream = CreateOnlineStream(recognizer);
+  const SherpaOnnxOnlineRecognizer *recognizer =
+      CreateOnlineRecognizer(&config);
+  const SherpaOnnxOnlineStream *stream = CreateOnlineStream(recognizer);
 
-  SherpaOnnxDisplay *display = CreateDisplay(50);
+  const SherpaOnnxDisplay *display = CreateDisplay(50);
   int32_t segment_id = 0;
 
   const char *wav_filename = argv[context.index];
diff --git a/c-api-examples/speaker-identification-c-api.c b/c-api-examples/speaker-identification-c-api.c
new file mode 100644
index 00000000..d1d428d6
--- /dev/null
+++ b/c-api-examples/speaker-identification-c-api.c
@@ -0,0 +1,256 @@
+// c-api-examples/speaker-identification-c-api.c
+//
+// Copyright (c)  2024  Xiaomi Corporation
+
+// We assume you have pre-downloaded the speaker embedding extractor model
+// from
+// https://github.com/k2-fsa/sherpa-onnx/releases/tag/speaker-recongition-models
+//
+// An example command to download
+// "3dspeaker_speech_campplus_sv_zh-cn_16k-common.onnx"
+// is given below:
+//
+// clang-format off
+//
+// wget https://github.com/k2-fsa/sherpa-onnx/releases/download/speaker-recongition-models/3dspeaker_speech_campplus_sv_zh-cn_16k-common.onnx
+//
+// clang-format on
+//
+// Also, please download the test wave files from
+//
+// https://github.com/csukuangfj/sr-data
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "sherpa-onnx/c-api/c-api.h"
+
+static const float *ComputeEmbedding(
+    const SherpaOnnxSpeakerEmbeddingExtractor *ex, const char *wav_filename) {
+  const SherpaOnnxWave *wave = SherpaOnnxReadWave(wav_filename);
+  if (wave == NULL) {
+    fprintf(stderr, "Failed to read %s\n", wav_filename);
+    exit(-1);
+  }
+
+  const SherpaOnnxOnlineStream *stream =
+      SherpaOnnxSpeakerEmbeddingExtractorCreateStream(ex);
+
+  AcceptWaveform(stream, wave->sample_rate, wave->samples, wave->num_samples);
+  InputFinished(stream);
+
+  if (!SherpaOnnxSpeakerEmbeddingExtractorIsReady(ex, stream)) {
+    fprintf(stderr, "The input wave file %s is too short!\n", wav_filename);
+    exit(-1);
+  }
+
+  // we will free `v` outside of this function
+  const float *v =
+      SherpaOnnxSpeakerEmbeddingExtractorComputeEmbedding(ex, stream);
+
+  DestroyOnlineStream(stream);
+  SherpaOnnxFreeWave(wave);
+
+  // Remeber to free v to avoid memory leak
+  return v;
+}
+
+int32_t main() {
+  SherpaOnnxSpeakerEmbeddingExtractorConfig config;
+
+  memset(&config, 0, sizeof(config));
+
+  // please download the model from
+  // https://github.com/k2-fsa/sherpa-onnx/releases/tag/speaker-recongition-models
+  config.model = "./3dspeaker_speech_campplus_sv_zh-cn_16k-common.onnx";
+
+  config.num_threads = 1;
+  config.debug = 0;
+  config.provider = "cpu";
+
+  const SherpaOnnxSpeakerEmbeddingExtractor *ex =
+      SherpaOnnxCreateSpeakerEmbeddingExtractor(&config);
+  if (!ex) {
+    fprintf(stderr, "Failed to create speaker embedding extractor");
+    return -1;
+  }
+
+  int32_t dim = SherpaOnnxSpeakerEmbeddingExtractorDim(ex);
+
+  const SherpaOnnxSpeakerEmbeddingManager *manager =
+      SherpaOnnxCreateSpeakerEmbeddingManager(dim);
+
+  // Please download the test data from
+  // https://github.com/csukuangfj/sr-data
+  const char *spk1_1 = "./sr-data/enroll/fangjun-sr-1.wav";
+  const char *spk1_2 = "./sr-data/enroll/fangjun-sr-2.wav";
+  const char *spk1_3 = "./sr-data/enroll/fangjun-sr-3.wav";
+
+  const char *spk2_1 = "./sr-data/enroll/leijun-sr-1.wav";
+  const char *spk2_2 = "./sr-data/enroll/leijun-sr-2.wav";
+
+  const float *spk1_vec[4] = {NULL};
+  spk1_vec[0] = ComputeEmbedding(ex, spk1_1);
+  spk1_vec[1] = ComputeEmbedding(ex, spk1_2);
+  spk1_vec[2] = ComputeEmbedding(ex, spk1_3);
+
+  const float *spk2_vec[3] = {NULL};
+  spk2_vec[0] = ComputeEmbedding(ex, spk2_1);
+  spk2_vec[1] = ComputeEmbedding(ex, spk2_2);
+
+  if (!SherpaOnnxSpeakerEmbeddingManagerAddList(manager, "fangjun", spk1_vec)) {
+    fprintf(stderr, "Failed to register fangjun\n");
+    exit(-1);
+  }
+
+  if (!SherpaOnnxSpeakerEmbeddingManagerContains(manager, "fangjun")) {
+    fprintf(stderr, "Failed to find fangjun\n");
+    exit(-1);
+  }
+
+  if (!SherpaOnnxSpeakerEmbeddingManagerAddList(manager, "leijun", spk2_vec)) {
+    fprintf(stderr, "Failed to register leijun\n");
+    exit(-1);
+  }
+
+  if (!SherpaOnnxSpeakerEmbeddingManagerContains(manager, "leijun")) {
+    fprintf(stderr, "Failed to find leijun\n");
+    exit(-1);
+  }
+
+  if (SherpaOnnxSpeakerEmbeddingManagerNumSpeakers(manager) != 2) {
+    fprintf(stderr, "There should be two speakers: fangjun and leijun\n");
+    exit(-1);
+  }
+
+  const char *const *all_speakers =
+      SherpaOnnxSpeakerEmbeddingManagerGetAllSpeakers(manager);
+  const char *const *p = all_speakers;
+  fprintf(stderr, "list of registered speakers\n-----\n");
+  while (p[0]) {
+    fprintf(stderr, "speaker: %s\n", p[0]);
+    ++p;
+  }
+  fprintf(stderr, "----\n");
+
+  SherpaOnnxSpeakerEmbeddingManagerFreeAllSpeakers(all_speakers);
+
+  const char *test1 = "./sr-data/test/fangjun-test-sr-1.wav";
+  const char *test2 = "./sr-data/test/leijun-test-sr-1.wav";
+  const char *test3 = "./sr-data/test/liudehua-test-sr-1.wav";
+
+  const float *v1 = ComputeEmbedding(ex, test1);
+  const float *v2 = ComputeEmbedding(ex, test2);
+  const float *v3 = ComputeEmbedding(ex, test3);
+
+  float threshold = 0.6;
+
+  const char *name1 =
+      SherpaOnnxSpeakerEmbeddingManagerSearch(manager, v1, threshold);
+  if (name1) {
+    fprintf(stderr, "%s: Found %s\n", test1, name1);
+    SherpaOnnxSpeakerEmbeddingManagerFreeSearch(name1);
+  } else {
+    fprintf(stderr, "%s: Not found\n", test1);
+  }
+
+  const char *name2 =
+      SherpaOnnxSpeakerEmbeddingManagerSearch(manager, v2, threshold);
+  if (name2) {
+    fprintf(stderr, "%s: Found %s\n", test2, name2);
+    SherpaOnnxSpeakerEmbeddingManagerFreeSearch(name2);
+  } else {
+    fprintf(stderr, "%s: Not found\n", test2);
+  }
+
+  const char *name3 =
+      SherpaOnnxSpeakerEmbeddingManagerSearch(manager, v3, threshold);
+  if (name3) {
+    fprintf(stderr, "%s: Found %s\n", test3, name3);
+    SherpaOnnxSpeakerEmbeddingManagerFreeSearch(name3);
+  } else {
+    fprintf(stderr, "%s: Not found\n", test3);
+  }
+
+  int32_t ok = SherpaOnnxSpeakerEmbeddingManagerVerify(manager, "fangjun", v1,
+                                                       threshold);
+  if (ok) {
+    fprintf(stderr, "%s matches fangjun\n", test1);
+  } else {
+    fprintf(stderr, "%s does NOT match fangjun\n", test1);
+  }
+
+  ok = SherpaOnnxSpeakerEmbeddingManagerVerify(manager, "fangjun", v2,
+                                               threshold);
+  if (ok) {
+    fprintf(stderr, "%s matches fangjun\n", test2);
+  } else {
+    fprintf(stderr, "%s does NOT match fangjun\n", test2);
+  }
+
+  fprintf(stderr, "Removing fangjun\n");
+  if (!SherpaOnnxSpeakerEmbeddingManagerRemove(manager, "fangjun")) {
+    fprintf(stderr, "Failed to remove fangjun\n");
+    exit(-1);
+  }
+
+  if (SherpaOnnxSpeakerEmbeddingManagerNumSpeakers(manager) != 1) {
+    fprintf(stderr, "There should be only 1 speaker left\n");
+    exit(-1);
+  }
+
+  name1 = SherpaOnnxSpeakerEmbeddingManagerSearch(manager, v1, threshold);
+  if (name1) {
+    fprintf(stderr, "%s: Found %s\n", test1, name1);
+    SherpaOnnxSpeakerEmbeddingManagerFreeSearch(name1);
+  } else {
+    fprintf(stderr, "%s: Not found\n", test1);
+  }
+
+  fprintf(stderr, "Removing leijun\n");
+  if (!SherpaOnnxSpeakerEmbeddingManagerRemove(manager, "leijun")) {
+    fprintf(stderr, "Failed to remove leijun\n");
+    exit(-1);
+  }
+
+  if (SherpaOnnxSpeakerEmbeddingManagerNumSpeakers(manager) != 0) {
+    fprintf(stderr, "There should be only 1 speaker left\n");
+    exit(-1);
+  }
+
+  name2 = SherpaOnnxSpeakerEmbeddingManagerSearch(manager, v2, threshold);
+  if (name2) {
+    fprintf(stderr, "%s: Found %s\n", test2, name2);
+    SherpaOnnxSpeakerEmbeddingManagerFreeSearch(name2);
+  } else {
+    fprintf(stderr, "%s: Not found\n", test2);
+  }
+
+  all_speakers = SherpaOnnxSpeakerEmbeddingManagerGetAllSpeakers(manager);
+
+  p = all_speakers;
+  fprintf(stderr, "list of registered speakers\n-----\n");
+  while (p[0]) {
+    fprintf(stderr, "speaker: %s\n", p[0]);
+    ++p;
+  }
+  fprintf(stderr, "----\n");
+
+  SherpaOnnxSpeakerEmbeddingManagerFreeAllSpeakers(all_speakers);
+  SherpaOnnxSpeakerEmbeddingExtractorDestroyEmbedding(v1);
+  SherpaOnnxSpeakerEmbeddingExtractorDestroyEmbedding(v2);
+  SherpaOnnxSpeakerEmbeddingExtractorDestroyEmbedding(v3);
+
+  SherpaOnnxSpeakerEmbeddingExtractorDestroyEmbedding(spk1_vec[0]);
+  SherpaOnnxSpeakerEmbeddingExtractorDestroyEmbedding(spk1_vec[1]);
+  SherpaOnnxSpeakerEmbeddingExtractorDestroyEmbedding(spk1_vec[2]);
+
+  SherpaOnnxSpeakerEmbeddingExtractorDestroyEmbedding(spk2_vec[0]);
+  SherpaOnnxSpeakerEmbeddingExtractorDestroyEmbedding(spk2_vec[1]);
+
+  SherpaOnnxDestroySpeakerEmbeddingManager(manager);
+  SherpaOnnxDestroySpeakerEmbeddingExtractor(ex);
+
+  return 0;
+}
diff --git a/c-api-examples/spoken-language-identification-c-api.c b/c-api-examples/spoken-language-identification-c-api.c
index b9911303..0c640c47 100644
--- a/c-api-examples/spoken-language-identification-c-api.c
+++ b/c-api-examples/spoken-language-identification-c-api.c
@@ -1,3 +1,6 @@
+// c-api-examples/spoken-language-identification-c-api.c
+//
+// Copyright (c)  2024  Xiaomi Corporation
 
 // We assume you have pre-downloaded the whisper multi-lingual models
 // from https://github.com/k2-fsa/sherpa-onnx/releases/tag/asr-models
diff --git a/ios-swift/SherpaOnnx/SherpaOnnx/ViewController.swift b/ios-swift/SherpaOnnx/SherpaOnnx/ViewController.swift
index 7153a354..200f6a20 100644
--- a/ios-swift/SherpaOnnx/SherpaOnnx/ViewController.swift
+++ b/ios-swift/SherpaOnnx/SherpaOnnx/ViewController.swift
@@ -83,7 +83,7 @@ class ViewController: UIViewController {
         // Please select one model that is best suitable for you.
         //
         // You can also modify Model.swift to add new pre-trained models from
-        // https://k2-fsa.github.io/sherpa/ncnn/pretrained_models/index.html
+        // https://k2-fsa.github.io/sherpa/onnx/pretrained_models/index.html
 
         // let modelConfig = getBilingualStreamZhEnZipformer20230220()
         // let modelConfig = getZhZipformer20230615()
diff --git a/ios-swiftui/SherpaOnnxTts/SherpaOnnxTts/ContentView.swift b/ios-swiftui/SherpaOnnxTts/SherpaOnnxTts/ContentView.swift
index fca8db7b..df1b3d34 100644
--- a/ios-swiftui/SherpaOnnxTts/SherpaOnnxTts/ContentView.swift
+++ b/ios-swiftui/SherpaOnnxTts/SherpaOnnxTts/ContentView.swift
@@ -4,7 +4,7 @@
 //
 //  Created by fangjun on 2023/11/23.
 //
-// Speech-to-text with Next-gen Kaldi on iOS without Internet connection
+// Text-to-speech with Next-gen Kaldi on iOS without Internet connection
 
 import SwiftUI
 import AVFoundation
diff --git a/python-api-examples/offline-tts-play.py b/python-api-examples/offline-tts-play.py
index 02442e69..ca3d66de 100755
--- a/python-api-examples/offline-tts-play.py
+++ b/python-api-examples/offline-tts-play.py
@@ -183,7 +183,7 @@ event = threading.Event()
 first_message_time = None
 
 
-def generated_audio_callback(samples: np.ndarray):
+def generated_audio_callback(samples: np.ndarray, progress: float):
     """This function is called whenever max_num_sentences sentences
     have been processed.
 
diff --git a/sherpa-onnx/c-api/c-api.cc b/sherpa-onnx/c-api/c-api.cc
index 14550fc8..685091c1 100644
--- a/sherpa-onnx/c-api/c-api.cc
+++ b/sherpa-onnx/c-api/c-api.cc
@@ -16,6 +16,8 @@
 #include "sherpa-onnx/csrc/macros.h"
 #include "sherpa-onnx/csrc/offline-recognizer.h"
 #include "sherpa-onnx/csrc/online-recognizer.h"
+#include "sherpa-onnx/csrc/speaker-embedding-extractor.h"
+#include "sherpa-onnx/csrc/speaker-embedding-manager.h"
 #include "sherpa-onnx/csrc/spoken-language-identification.h"
 #include "sherpa-onnx/csrc/voice-activity-detector.h"
 #include "sherpa-onnx/csrc/wave-reader.h"
@@ -114,7 +116,7 @@ SherpaOnnxOnlineRecognizer *CreateOnlineRecognizer(
   return recognizer;
 }
 
-void DestroyOnlineRecognizer(SherpaOnnxOnlineRecognizer *recognizer) {
+void DestroyOnlineRecognizer(const SherpaOnnxOnlineRecognizer *recognizer) {
   delete recognizer;
 }
 
@@ -132,25 +134,28 @@ SherpaOnnxOnlineStream *CreateOnlineStreamWithHotwords(
   return stream;
 }
 
-void DestroyOnlineStream(SherpaOnnxOnlineStream *stream) { delete stream; }
+void DestroyOnlineStream(const SherpaOnnxOnlineStream *stream) {
+  delete stream;
+}
 
-void AcceptWaveform(SherpaOnnxOnlineStream *stream, int32_t sample_rate,
+void AcceptWaveform(const SherpaOnnxOnlineStream *stream, int32_t sample_rate,
                     const float *samples, int32_t n) {
   stream->impl->AcceptWaveform(sample_rate, samples, n);
 }
 
-int32_t IsOnlineStreamReady(SherpaOnnxOnlineRecognizer *recognizer,
-                            SherpaOnnxOnlineStream *stream) {
+int32_t IsOnlineStreamReady(const SherpaOnnxOnlineRecognizer *recognizer,
+                            const SherpaOnnxOnlineStream *stream) {
   return recognizer->impl->IsReady(stream->impl.get());
 }
 
-void DecodeOnlineStream(SherpaOnnxOnlineRecognizer *recognizer,
-                        SherpaOnnxOnlineStream *stream) {
+void DecodeOnlineStream(const SherpaOnnxOnlineRecognizer *recognizer,
+                        const SherpaOnnxOnlineStream *stream) {
   recognizer->impl->DecodeStream(stream->impl.get());
 }
 
-void DecodeMultipleOnlineStreams(SherpaOnnxOnlineRecognizer *recognizer,
-                                 SherpaOnnxOnlineStream **streams, int32_t n) {
+void DecodeMultipleOnlineStreams(const SherpaOnnxOnlineRecognizer *recognizer,
+                                 const SherpaOnnxOnlineStream **streams,
+                                 int32_t n) {
   std::vector<sherpa_onnx::OnlineStream *> ss(n);
   for (int32_t i = 0; i != n; ++i) {
     ss[i] = streams[i]->impl.get();
@@ -159,7 +164,8 @@ void DecodeMultipleOnlineStreams(SherpaOnnxOnlineRecognizer *recognizer,
 }
 
 const SherpaOnnxOnlineRecognizerResult *GetOnlineStreamResult(
-    SherpaOnnxOnlineRecognizer *recognizer, SherpaOnnxOnlineStream *stream) {
+    const SherpaOnnxOnlineRecognizer *recognizer,
+    const SherpaOnnxOnlineStream *stream) {
   sherpa_onnx::OnlineRecognizerResult result =
       recognizer->impl->GetResult(stream->impl.get());
   const auto &text = result.text;
@@ -232,29 +238,30 @@ void DestroyOnlineRecognizerResult(const SherpaOnnxOnlineRecognizerResult *r) {
   }
 }
 
-void Reset(SherpaOnnxOnlineRecognizer *recognizer,
-           SherpaOnnxOnlineStream *stream) {
+void Reset(const SherpaOnnxOnlineRecognizer *recognizer,
+           const SherpaOnnxOnlineStream *stream) {
   recognizer->impl->Reset(stream->impl.get());
 }
 
-void InputFinished(SherpaOnnxOnlineStream *stream) {
+void InputFinished(const SherpaOnnxOnlineStream *stream) {
   stream->impl->InputFinished();
 }
 
-int32_t IsEndpoint(SherpaOnnxOnlineRecognizer *recognizer,
-                   SherpaOnnxOnlineStream *stream) {
+int32_t IsEndpoint(const SherpaOnnxOnlineRecognizer *recognizer,
+                   const SherpaOnnxOnlineStream *stream) {
   return recognizer->impl->IsEndpoint(stream->impl.get());
 }
 
-SherpaOnnxDisplay *CreateDisplay(int32_t max_word_per_line) {
+const SherpaOnnxDisplay *CreateDisplay(int32_t max_word_per_line) {
   SherpaOnnxDisplay *ans = new SherpaOnnxDisplay;
   ans->impl = std::make_unique<sherpa_onnx::Display>(max_word_per_line);
   return ans;
 }
 
-void DestroyDisplay(SherpaOnnxDisplay *display) { delete display; }
+void DestroyDisplay(const SherpaOnnxDisplay *display) { delete display; }
 
-void SherpaOnnxPrint(SherpaOnnxDisplay *display, int32_t idx, const char *s) {
+void SherpaOnnxPrint(const SherpaOnnxDisplay *display, int32_t idx,
+                     const char *s) {
   display->impl->Print(idx, s);
 }
 
@@ -808,9 +815,8 @@ int32_t SherpaOnnxOfflineTtsNumSpeakers(const SherpaOnnxOfflineTts *tts) {
 }
 
 static const SherpaOnnxGeneratedAudio *SherpaOnnxOfflineTtsGenerateInternal(
-    const SherpaOnnxOfflineTts *tts, const char *text, int32_t sid,
-    float speed, std::function<void(const float *, int32_t, float)> callback) 
-{
+    const SherpaOnnxOfflineTts *tts, const char *text, int32_t sid, float speed,
+    std::function<void(const float *, int32_t, float)> callback) {
   sherpa_onnx::GeneratedAudio audio =
       tts->impl->Generate(text, sid, speed, callback);
 
@@ -833,36 +839,37 @@ static const SherpaOnnxGeneratedAudio *SherpaOnnxOfflineTtsGenerateInternal(
 const SherpaOnnxGeneratedAudio *SherpaOnnxOfflineTtsGenerate(
     const SherpaOnnxOfflineTts *tts, const char *text, int32_t sid,
     float speed) {
-  return SherpaOnnxOfflineTtsGenerateInternal( tts, text, sid, speed, nullptr );
+  return SherpaOnnxOfflineTtsGenerateInternal(tts, text, sid, speed, nullptr);
 }
 
 const SherpaOnnxGeneratedAudio *SherpaOnnxOfflineTtsGenerateWithCallback(
     const SherpaOnnxOfflineTts *tts, const char *text, int32_t sid, float speed,
     SherpaOnnxGeneratedAudioCallback callback) {
-  auto wrapper = [callback](const float *samples, int32_t n, float /*progress*/) {
-    callback(samples, n );
-  };
+  auto wrapper = [callback](const float *samples, int32_t n,
+                            float /*progress*/) { callback(samples, n); };
 
-  return SherpaOnnxOfflineTtsGenerateInternal( tts, text, sid, speed, wrapper );
+  return SherpaOnnxOfflineTtsGenerateInternal(tts, text, sid, speed, wrapper);
 }
 
-const SherpaOnnxGeneratedAudio *SherpaOnnxOfflineTtsGenerateWithProgressCallback(
+const SherpaOnnxGeneratedAudio *
+SherpaOnnxOfflineTtsGenerateWithProgressCallback(
     const SherpaOnnxOfflineTts *tts, const char *text, int32_t sid, float speed,
     SherpaOnnxGeneratedAudioProgressCallback callback) {
   auto wrapper = [callback](const float *samples, int32_t n, float progress) {
-    callback(samples, n, progress );
+    callback(samples, n, progress);
   };
-  return SherpaOnnxOfflineTtsGenerateInternal( tts, text, sid, speed, wrapper );
+  return SherpaOnnxOfflineTtsGenerateInternal(tts, text, sid, speed, wrapper);
 }
 
 const SherpaOnnxGeneratedAudio *SherpaOnnxOfflineTtsGenerateWithCallbackWithArg(
     const SherpaOnnxOfflineTts *tts, const char *text, int32_t sid, float speed,
     SherpaOnnxGeneratedAudioCallbackWithArg callback, void *arg) {
-  auto wrapper = [callback, arg](const float *samples, int32_t n, float /*progress*/) {
+  auto wrapper = [callback, arg](const float *samples, int32_t n,
+                                 float /*progress*/) {
     callback(samples, n, arg);
   };
 
-  return SherpaOnnxOfflineTtsGenerateInternal( tts, text, sid, speed, wrapper );
+  return SherpaOnnxOfflineTtsGenerateInternal(tts, text, sid, speed, wrapper);
 }
 
 void SherpaOnnxDestroyOfflineTtsGeneratedAudio(
@@ -972,3 +979,200 @@ void SherpaOnnxDestroySpokenLanguageIdentificationResult(
     delete r;
   }
 }
+
+struct SherpaOnnxSpeakerEmbeddingExtractor {
+  std::unique_ptr<sherpa_onnx::SpeakerEmbeddingExtractor> impl;
+};
+
+const SherpaOnnxSpeakerEmbeddingExtractor *
+SherpaOnnxCreateSpeakerEmbeddingExtractor(
+    const SherpaOnnxSpeakerEmbeddingExtractorConfig *config) {
+  sherpa_onnx::SpeakerEmbeddingExtractorConfig c;
+  c.model = SHERPA_ONNX_OR(config->model, "");
+
+  c.num_threads = SHERPA_ONNX_OR(config->num_threads, 1);
+  c.debug = SHERPA_ONNX_OR(config->debug, 0);
+  c.provider = SHERPA_ONNX_OR(config->provider, "cpu");
+
+  if (config->debug) {
+    SHERPA_ONNX_LOGE("%s\n", c.ToString().c_str());
+  }
+
+  if (!c.Validate()) {
+    SHERPA_ONNX_LOGE("Errors in config!");
+    return nullptr;
+  }
+
+  auto p = new SherpaOnnxSpeakerEmbeddingExtractor;
+
+  p->impl = std::make_unique<sherpa_onnx::SpeakerEmbeddingExtractor>(c);
+
+  return p;
+}
+
+void SherpaOnnxDestroySpeakerEmbeddingExtractor(
+    const SherpaOnnxSpeakerEmbeddingExtractor *p) {
+  delete p;
+}
+
+int32_t SherpaOnnxSpeakerEmbeddingExtractorDim(
+    const SherpaOnnxSpeakerEmbeddingExtractor *p) {
+  return p->impl->Dim();
+}
+
+const SherpaOnnxOnlineStream *SherpaOnnxSpeakerEmbeddingExtractorCreateStream(
+    const SherpaOnnxSpeakerEmbeddingExtractor *p) {
+  SherpaOnnxOnlineStream *stream =
+      new SherpaOnnxOnlineStream(p->impl->CreateStream());
+  return stream;
+}
+
+int32_t SherpaOnnxSpeakerEmbeddingExtractorIsReady(
+    const SherpaOnnxSpeakerEmbeddingExtractor *p,
+    const SherpaOnnxOnlineStream *s) {
+  return p->impl->IsReady(s->impl.get());
+}
+
+const float *SherpaOnnxSpeakerEmbeddingExtractorComputeEmbedding(
+    const SherpaOnnxSpeakerEmbeddingExtractor *p,
+    const SherpaOnnxOnlineStream *s) {
+  std::vector<float> v = p->impl->Compute(s->impl.get());
+  float *ans = new float[v.size()];
+  std::copy(v.begin(), v.end(), ans);
+  return ans;
+}
+
+void SherpaOnnxSpeakerEmbeddingExtractorDestroyEmbedding(const float *v) {
+  delete[] v;
+}
+
+struct SherpaOnnxSpeakerEmbeddingManager {
+  std::unique_ptr<sherpa_onnx::SpeakerEmbeddingManager> impl;
+};
+
+const SherpaOnnxSpeakerEmbeddingManager *
+SherpaOnnxCreateSpeakerEmbeddingManager(int32_t dim) {
+  auto p = new SherpaOnnxSpeakerEmbeddingManager;
+  p->impl = std::make_unique<sherpa_onnx::SpeakerEmbeddingManager>(dim);
+  return p;
+}
+
+void SherpaOnnxDestroySpeakerEmbeddingManager(
+    const SherpaOnnxSpeakerEmbeddingManager *p) {
+  delete p;
+}
+
+int32_t SherpaOnnxSpeakerEmbeddingManagerAdd(
+    const SherpaOnnxSpeakerEmbeddingManager *p, const char *name,
+    const float *v) {
+  return p->impl->Add(name, v);
+}
+
+int32_t SherpaOnnxSpeakerEmbeddingManagerAddList(
+    const SherpaOnnxSpeakerEmbeddingManager *p, const char *name,
+    const float **v) {
+  int32_t n = 0;
+  auto q = v;
+  while (q && q[0]) {
+    ++n;
+    ++q;
+  }
+
+  if (n == 0) {
+    SHERPA_ONNX_LOGE("Empty embedding!");
+    return 0;
+  }
+
+  std::vector<std::vector<float>> vec(n);
+  int32_t dim = p->impl->Dim();
+
+  for (int32_t i = 0; i != n; ++i) {
+    vec[i] = std::vector<float>(v[i], v[i] + dim);
+  }
+
+  return p->impl->Add(name, vec);
+}
+
+int32_t SherpaOnnxSpeakerEmbeddingManagerAddListFlattened(
+    const SherpaOnnxSpeakerEmbeddingManager *p, const char *name,
+    const float *v, int32_t n) {
+  std::vector<std::vector<float>> vec(n);
+
+  int32_t dim = p->impl->Dim();
+
+  for (int32_t i = 0; i != n; ++i, v += dim) {
+    vec[i] = std::vector<float>(v, v + dim);
+  }
+
+  return p->impl->Add(name, vec);
+}
+
+int32_t SherpaOnnxSpeakerEmbeddingManagerRemove(
+    const SherpaOnnxSpeakerEmbeddingManager *p, const char *name) {
+  return p->impl->Remove(name);
+}
+
+const char *SherpaOnnxSpeakerEmbeddingManagerSearch(
+    const SherpaOnnxSpeakerEmbeddingManager *p, const float *v,
+    float threshold) {
+  auto r = p->impl->Search(v, threshold);
+  if (r.empty()) {
+    return nullptr;
+  }
+
+  char *name = new char[r.size() + 1];
+  std::copy(r.begin(), r.end(), name);
+  name[r.size()] = '\0';
+
+  return name;
+}
+
+void SherpaOnnxSpeakerEmbeddingManagerFreeSearch(const char *name) {
+  delete[] name;
+}
+
+int32_t SherpaOnnxSpeakerEmbeddingManagerVerify(
+    const SherpaOnnxSpeakerEmbeddingManager *p, const char *name,
+    const float *v, float threshold) {
+  return p->impl->Verify(name, v, threshold);
+}
+
+int32_t SherpaOnnxSpeakerEmbeddingManagerContains(
+    const SherpaOnnxSpeakerEmbeddingManager *p, const char *name) {
+  return p->impl->Contains(name);
+}
+
+int32_t SherpaOnnxSpeakerEmbeddingManagerNumSpeakers(
+    const SherpaOnnxSpeakerEmbeddingManager *p) {
+  return p->impl->NumSpeakers();
+}
+
+const char *const *SherpaOnnxSpeakerEmbeddingManagerGetAllSpeakers(
+    const SherpaOnnxSpeakerEmbeddingManager *manager) {
+  std::vector<std::string> all_speakers = manager->impl->GetAllSpeakers();
+  int32_t num_speakers = all_speakers.size();
+  char **p = new char *[num_speakers + 1];
+  p[num_speakers] = nullptr;
+
+  int32_t i = 0;
+  for (const auto &name : all_speakers) {
+    p[i] = new char[name.size() + 1];
+    std::copy(name.begin(), name.end(), p[i]);
+    p[i][name.size()] = '\0';
+
+    i += 1;
+  }
+  return p;
+}
+
+void SherpaOnnxSpeakerEmbeddingManagerFreeAllSpeakers(
+    const char *const *names) {
+  auto p = names;
+
+  while (p && p[0]) {
+    delete[] p[0];
+    ++p;
+  }
+
+  delete[] names;
+}
diff --git a/sherpa-onnx/c-api/c-api.h b/sherpa-onnx/c-api/c-api.h
index 8c86f353..66c33bf2 100644
--- a/sherpa-onnx/c-api/c-api.h
+++ b/sherpa-onnx/c-api/c-api.h
@@ -186,7 +186,7 @@ SHERPA_ONNX_API SherpaOnnxOnlineRecognizer *CreateOnlineRecognizer(
 ///
 /// @param p A pointer returned by CreateOnlineRecognizer()
 SHERPA_ONNX_API void DestroyOnlineRecognizer(
-    SherpaOnnxOnlineRecognizer *recognizer);
+    const SherpaOnnxOnlineRecognizer *recognizer);
 
 /// Create an online stream for accepting wave samples.
 ///
@@ -208,7 +208,7 @@ SHERPA_ONNX_API SherpaOnnxOnlineStream *CreateOnlineStreamWithHotwords(
 /// Destroy an online stream.
 ///
 /// @param stream A pointer returned by CreateOnlineStream()
-SHERPA_ONNX_API void DestroyOnlineStream(SherpaOnnxOnlineStream *stream);
+SHERPA_ONNX_API void DestroyOnlineStream(const SherpaOnnxOnlineStream *stream);
 
 /// Accept input audio samples and compute the features.
 /// The user has to invoke DecodeOnlineStream() to run the neural network and
@@ -221,7 +221,7 @@ SHERPA_ONNX_API void DestroyOnlineStream(SherpaOnnxOnlineStream *stream);
 /// @param samples A pointer to a 1-D array containing audio samples.
 ///                The range of samples has to be normalized to [-1, 1].
 /// @param n  Number of elements in the samples array.
-SHERPA_ONNX_API void AcceptWaveform(SherpaOnnxOnlineStream *stream,
+SHERPA_ONNX_API void AcceptWaveform(const SherpaOnnxOnlineStream *stream,
                                     int32_t sample_rate, const float *samples,
                                     int32_t n);
 
@@ -230,8 +230,9 @@ SHERPA_ONNX_API void AcceptWaveform(SherpaOnnxOnlineStream *stream,
 ///
 /// @param recognizer  A pointer returned by CreateOnlineRecognizer
 /// @param stream  A pointer returned by CreateOnlineStream
-SHERPA_ONNX_API int32_t IsOnlineStreamReady(
-    SherpaOnnxOnlineRecognizer *recognizer, SherpaOnnxOnlineStream *stream);
+SHERPA_ONNX_API int32_t
+IsOnlineStreamReady(const SherpaOnnxOnlineRecognizer *recognizer,
+                    const SherpaOnnxOnlineStream *stream);
 
 /// Call this function to run the neural network model and decoding.
 //
@@ -243,8 +244,9 @@ SHERPA_ONNX_API int32_t IsOnlineStreamReady(
 ///     DecodeOnlineStream(recognizer, stream);
 ///  }
 ///
-SHERPA_ONNX_API void DecodeOnlineStream(SherpaOnnxOnlineRecognizer *recognizer,
-                                        SherpaOnnxOnlineStream *stream);
+SHERPA_ONNX_API void DecodeOnlineStream(
+    const SherpaOnnxOnlineRecognizer *recognizer,
+    const SherpaOnnxOnlineStream *stream);
 
 /// This function is similar to DecodeOnlineStream(). It decodes multiple
 /// OnlineStream in parallel.
@@ -257,8 +259,8 @@ SHERPA_ONNX_API void DecodeOnlineStream(SherpaOnnxOnlineRecognizer *recognizer,
 ///                 CreateOnlineRecognizer()
 /// @param n  Number of elements in the given streams array.
 SHERPA_ONNX_API void DecodeMultipleOnlineStreams(
-    SherpaOnnxOnlineRecognizer *recognizer, SherpaOnnxOnlineStream **streams,
-    int32_t n);
+    const SherpaOnnxOnlineRecognizer *recognizer,
+    const SherpaOnnxOnlineStream **streams, int32_t n);
 
 /// Get the decoding results so far for an OnlineStream.
 ///
@@ -268,7 +270,8 @@ SHERPA_ONNX_API void DecodeMultipleOnlineStreams(
 ///         DestroyOnlineRecognizerResult() to free the returned pointer to
 ///         avoid memory leak.
 SHERPA_ONNX_API const SherpaOnnxOnlineRecognizerResult *GetOnlineStreamResult(
-    SherpaOnnxOnlineRecognizer *recognizer, SherpaOnnxOnlineStream *stream);
+    const SherpaOnnxOnlineRecognizer *recognizer,
+    const SherpaOnnxOnlineStream *stream);
 
 /// Destroy the pointer returned by GetOnlineStreamResult().
 ///
@@ -281,35 +284,36 @@ SHERPA_ONNX_API void DestroyOnlineRecognizerResult(
 ///
 /// @param recognizer A pointer returned by CreateOnlineRecognizer().
 /// @param stream A pointer returned by CreateOnlineStream
-SHERPA_ONNX_API void Reset(SherpaOnnxOnlineRecognizer *recognizer,
-                           SherpaOnnxOnlineStream *stream);
+SHERPA_ONNX_API void Reset(const SherpaOnnxOnlineRecognizer *recognizer,
+                           const SherpaOnnxOnlineStream *stream);
 
 /// Signal that no more audio samples would be available.
 /// After this call, you cannot call AcceptWaveform() any more.
 ///
 /// @param stream A pointer returned by CreateOnlineStream()
-SHERPA_ONNX_API void InputFinished(SherpaOnnxOnlineStream *stream);
+SHERPA_ONNX_API void InputFinished(const SherpaOnnxOnlineStream *stream);
 
 /// Return 1 if an endpoint has been detected.
 ///
 /// @param recognizer A pointer returned by CreateOnlineRecognizer()
 /// @param stream A pointer returned by CreateOnlineStream()
 /// @return Return 1 if an endpoint is detected. Return 0 otherwise.
-SHERPA_ONNX_API int32_t IsEndpoint(SherpaOnnxOnlineRecognizer *recognizer,
-                                   SherpaOnnxOnlineStream *stream);
+SHERPA_ONNX_API int32_t IsEndpoint(const SherpaOnnxOnlineRecognizer *recognizer,
+                                   const SherpaOnnxOnlineStream *stream);
 
 // for displaying results on Linux/macOS.
 SHERPA_ONNX_API typedef struct SherpaOnnxDisplay SherpaOnnxDisplay;
 
 /// Create a display object. Must be freed using DestroyDisplay to avoid
 /// memory leak.
-SHERPA_ONNX_API SherpaOnnxDisplay *CreateDisplay(int32_t max_word_per_line);
+SHERPA_ONNX_API const SherpaOnnxDisplay *CreateDisplay(
+    int32_t max_word_per_line);
 
-SHERPA_ONNX_API void DestroyDisplay(SherpaOnnxDisplay *display);
+SHERPA_ONNX_API void DestroyDisplay(const SherpaOnnxDisplay *display);
 
 /// Print the result.
-SHERPA_ONNX_API void SherpaOnnxPrint(SherpaOnnxDisplay *display, int32_t idx,
-                                     const char *s);
+SHERPA_ONNX_API void SherpaOnnxPrint(const SherpaOnnxDisplay *display,
+                                     int32_t idx, const char *s);
 // ============================================================
 // For offline ASR (i.e., non-streaming ASR)
 // ============================================================
@@ -769,7 +773,7 @@ typedef void (*SherpaOnnxGeneratedAudioCallbackWithArg)(const float *samples,
                                                         int32_t n, void *arg);
 
 typedef void (*SherpaOnnxGeneratedAudioProgressCallback)(const float *samples,
-                                                 int32_t n, float p);
+                                                         int32_t n, float p);
 
 SHERPA_ONNX_API typedef struct SherpaOnnxOfflineTts SherpaOnnxOfflineTts;
 
@@ -839,7 +843,9 @@ SHERPA_ONNX_API const SherpaOnnxWave *SherpaOnnxReadWave(const char *filename);
 
 SHERPA_ONNX_API void SherpaOnnxFreeWave(const SherpaOnnxWave *wave);
 
-// Spoken language identification
+// ============================================================
+// For spoken language identification
+// ============================================================
 
 SHERPA_ONNX_API typedef struct
     SherpaOnnxSpokenLanguageIdentificationWhisperConfig {
@@ -893,6 +899,169 @@ SherpaOnnxSpokenLanguageIdentificationCompute(
 SHERPA_ONNX_API void SherpaOnnxDestroySpokenLanguageIdentificationResult(
     const SherpaOnnxSpokenLanguageIdentificationResult *r);
 
+// ============================================================
+// For speaker embedding extraction
+// ============================================================
+SHERPA_ONNX_API typedef struct SherpaOnnxSpeakerEmbeddingExtractorConfig {
+  const char *model;
+  int32_t num_threads;
+  int32_t debug;
+  const char *provider;
+} SherpaOnnxSpeakerEmbeddingExtractorConfig;
+
+SHERPA_ONNX_API typedef struct SherpaOnnxSpeakerEmbeddingExtractor
+    SherpaOnnxSpeakerEmbeddingExtractor;
+
+// The user has to invoke SherpaOnnxDestroySpeakerEmbeddingExtractor()
+// to free the returned pointer to avoid memory leak
+SHERPA_ONNX_API const SherpaOnnxSpeakerEmbeddingExtractor *
+SherpaOnnxCreateSpeakerEmbeddingExtractor(
+    const SherpaOnnxSpeakerEmbeddingExtractorConfig *config);
+
+SHERPA_ONNX_API void SherpaOnnxDestroySpeakerEmbeddingExtractor(
+    const SherpaOnnxSpeakerEmbeddingExtractor *p);
+
+SHERPA_ONNX_API int32_t SherpaOnnxSpeakerEmbeddingExtractorDim(
+    const SherpaOnnxSpeakerEmbeddingExtractor *p);
+
+// The user has to invoke DestroyOnlineStream() to free the returned pointer
+// to avoid memory leak
+SHERPA_ONNX_API const SherpaOnnxOnlineStream *
+SherpaOnnxSpeakerEmbeddingExtractorCreateStream(
+    const SherpaOnnxSpeakerEmbeddingExtractor *p);
+
+// Return 1 if the stream has enough feature frames for computing embeddings.
+// Return 0 otherwise.
+SHERPA_ONNX_API int32_t SherpaOnnxSpeakerEmbeddingExtractorIsReady(
+    const SherpaOnnxSpeakerEmbeddingExtractor *p,
+    const SherpaOnnxOnlineStream *s);
+
+// Compute the embedding of the stream.
+//
+// @return Return a pointer pointing to an array containing the embedding.
+// The length of the array is `dim` as returned by
+// SherpaOnnxSpeakerEmbeddingExtractorDim(p)
+//
+// The user has to invoke SherpaOnnxSpeakerEmbeddingExtractorDestroyEmbedding()
+// to free the returned pointer to avoid memory leak.
+SHERPA_ONNX_API const float *
+SherpaOnnxSpeakerEmbeddingExtractorComputeEmbedding(
+    const SherpaOnnxSpeakerEmbeddingExtractor *p,
+    const SherpaOnnxOnlineStream *s);
+
+SHERPA_ONNX_API void SherpaOnnxSpeakerEmbeddingExtractorDestroyEmbedding(
+    const float *v);
+
+SHERPA_ONNX_API typedef struct SherpaOnnxSpeakerEmbeddingManager
+    SherpaOnnxSpeakerEmbeddingManager;
+
+// The user has to invoke SherpaOnnxDestroySpeakerEmbeddingManager()
+// to free the returned pointer to avoid memory leak
+SHERPA_ONNX_API const SherpaOnnxSpeakerEmbeddingManager *
+SherpaOnnxCreateSpeakerEmbeddingManager(int32_t dim);
+
+SHERPA_ONNX_API void SherpaOnnxDestroySpeakerEmbeddingManager(
+    const SherpaOnnxSpeakerEmbeddingManager *p);
+
+// Register the embedding of a user
+//
+// @param name  The name of the user
+// @param p Pointer to an array containing the embeddings. The length of the
+//          array must be equal to `dim` used to construct the manager `p`.
+//
+// @return Return 1 if added successfully. Return 0 on error
+SHERPA_ONNX_API int32_t
+SherpaOnnxSpeakerEmbeddingManagerAdd(const SherpaOnnxSpeakerEmbeddingManager *p,
+                                     const char *name, const float *v);
+
+// @param v Pointer to an array of embeddings. If there are n embeddings, then
+//          v[0] is the pointer to the 0-th array containing the embeddings
+//          v[1] is the pointer to the 1-st array containing the embeddings
+//          v[n-1] is the pointer to the last array containing the embeddings
+//          v[n] is a NULL pointer
+// @return Return 1 if added successfully. Return 0 on error
+SHERPA_ONNX_API int32_t SherpaOnnxSpeakerEmbeddingManagerAddList(
+    const SherpaOnnxSpeakerEmbeddingManager *p, const char *name,
+    const float **v);
+
+// Similar to SherpaOnnxSpeakerEmbeddingManagerAddList() but the memory
+// is flattened.
+//
+// The length of the input array should be `n * dim`.
+//
+// @return Return 1 if added successfully. Return 0 on error
+SHERPA_ONNX_API int32_t SherpaOnnxSpeakerEmbeddingManagerAddListFlattened(
+    const SherpaOnnxSpeakerEmbeddingManager *p, const char *name,
+    const float *v, int32_t n);
+
+// Remove a user.
+// @param naem The name of the user to remove.
+// @return Return 1 if removed successfully; return 0 on error.
+//
+// Note if the user does not exist, it also returns 0.
+SHERPA_ONNX_API int32_t SherpaOnnxSpeakerEmbeddingManagerRemove(
+    const SherpaOnnxSpeakerEmbeddingManager *p, const char *name);
+
+// Search if an existing users' embedding matches the given one.
+//
+// @param p Pointer to an array containing the embedding. The dim
+//          of the array must equal to `dim` used to construct the manager `p`.
+// @param threshold A value between 0 and 1. If the similarity score exceeds
+//                  this threshold, we say a match is found.
+// @return Returns the name of the user if found. Return NULL if not found.
+//         If not NULL, the caller has to invoke
+//          SherpaOnnxSpeakerEmbeddingManagerFreeSearch() to free the returned
+//          pointer to avoid memory leak.
+SHERPA_ONNX_API const char *SherpaOnnxSpeakerEmbeddingManagerSearch(
+    const SherpaOnnxSpeakerEmbeddingManager *p, const float *v,
+    float threshold);
+
+SHERPA_ONNX_API void SherpaOnnxSpeakerEmbeddingManagerFreeSearch(
+    const char *name);
+
+// Check whether the input embedding matches the embedding of the input
+// speaker.
+//
+// It is for speaker verification.
+//
+// @param name The target speaker name.
+// @param p The input embedding to check.
+// @param threshold A value between 0 and 1.
+// @return Return 1 if it matches. Otherwise, it returns 0.
+SHERPA_ONNX_API int32_t SherpaOnnxSpeakerEmbeddingManagerVerify(
+    const SherpaOnnxSpeakerEmbeddingManager *p, const char *name,
+    const float *v, float threshold);
+
+// Return 1 if the user with the name is in the manager.
+// Return 0 if the user does not exist.
+SHERPA_ONNX_API int32_t SherpaOnnxSpeakerEmbeddingManagerContains(
+    const SherpaOnnxSpeakerEmbeddingManager *p, const char *name);
+
+// Return number of speakers in the manager.
+SHERPA_ONNX_API int32_t SherpaOnnxSpeakerEmbeddingManagerNumSpeakers(
+    const SherpaOnnxSpeakerEmbeddingManager *p);
+
+// Return the name of all speakers in the manager.
+//
+// @return Return an array of pointers `ans`. If there are n speakers, then
+// - ans[0] contains the name of the 0-th speaker
+// - ans[1] contains the name of the 1-st speaker
+// - ans[n-1] contains the name of the last speaker
+// - ans[n] is NULL
+// If there are no users at all, then ans[0] is NULL. In any case,
+// `ans` is not NULL.
+//
+// Each name is NULL-terminated
+//
+// The caller has to invoke SherpaOnnxSpeakerEmbeddingManagerFreeAllSpeakers()
+// to free the returned pointer to avoid memory leak.
+SHERPA_ONNX_API const char *const *
+SherpaOnnxSpeakerEmbeddingManagerGetAllSpeakers(
+    const SherpaOnnxSpeakerEmbeddingManager *p);
+
+SHERPA_ONNX_API void SherpaOnnxSpeakerEmbeddingManagerFreeAllSpeakers(
+    const char *const *names);
+
 #if defined(__GNUC__)
 #pragma GCC diagnostic pop
 #endif
diff --git a/sherpa-onnx/csrc/offline-tts-vits-impl.h b/sherpa-onnx/csrc/offline-tts-vits-impl.h
index cdd33e18..6bcfc0ca 100644
--- a/sherpa-onnx/csrc/offline-tts-vits-impl.h
+++ b/sherpa-onnx/csrc/offline-tts-vits-impl.h
@@ -168,7 +168,8 @@ class OfflineTtsVitsImpl : public OfflineTtsImpl {
       ans.samples.insert(ans.samples.end(), audio.samples.begin(),
                          audio.samples.end());
       if (callback) {
-        callback(audio.samples.data(), audio.samples.size(), b * 1.0 / num_batches);
+        callback(audio.samples.data(), audio.samples.size(),
+                 b * 1.0 / num_batches);
         // Caution(fangjun): audio is freed when the callback returns, so users
         // should copy the data if they want to access the data after
         // the callback returns to avoid segmentation fault.
diff --git a/sherpa-onnx/csrc/offline-tts.h b/sherpa-onnx/csrc/offline-tts.h
index c39dfdae..354057bf 100644
--- a/sherpa-onnx/csrc/offline-tts.h
+++ b/sherpa-onnx/csrc/offline-tts.h
@@ -54,8 +54,8 @@ struct GeneratedAudio {
 
 class OfflineTtsImpl;
 
-using GeneratedAudioCallback =
-    std::function<void(const float * /*samples*/, int32_t /*n*/, float /*progress*/)>;
+using GeneratedAudioCallback = std::function<void(
+    const float * /*samples*/, int32_t /*n*/, float /*progress*/)>;
 
 class OfflineTts {
  public:
diff --git a/sherpa-onnx/csrc/sherpa-onnx-offline-tts-play-alsa.cc b/sherpa-onnx/csrc/sherpa-onnx-offline-tts-play-alsa.cc
index 2cb17bd6..33b4f193 100644
--- a/sherpa-onnx/csrc/sherpa-onnx-offline-tts-play-alsa.cc
+++ b/sherpa-onnx/csrc/sherpa-onnx-offline-tts-play-alsa.cc
@@ -44,7 +44,8 @@ static void Handler(int32_t /*sig*/) {
   fprintf(stderr, "\nCaught Ctrl + C. Exiting\n");
 }
 
-static void AudioGeneratedCallback(const float *s, int32_t n) {
+static void AudioGeneratedCallback(const float *s, int32_t n,
+                                   float /*progress*/) {
   if (n > 0) {
     std::lock_guard<std::mutex> lock(g_buffer.mutex);
     g_buffer.samples.push({s, s + n});
diff --git a/sherpa-onnx/csrc/sherpa-onnx-offline-tts-play.cc b/sherpa-onnx/csrc/sherpa-onnx-offline-tts-play.cc
index c6dee345..8c919702 100644
--- a/sherpa-onnx/csrc/sherpa-onnx-offline-tts-play.cc
+++ b/sherpa-onnx/csrc/sherpa-onnx-offline-tts-play.cc
@@ -47,7 +47,8 @@ static void Handler(int32_t /*sig*/) {
   fprintf(stderr, "\nCaught Ctrl + C. Exiting\n");
 }
 
-static void AudioGeneratedCallback(const float *s, int32_t n, float /*progress*/) {
+static void AudioGeneratedCallback(const float *s, int32_t n,
+                                   float /*progress*/) {
   if (n > 0) {
     Samples samples;
     samples.data = std::vector<float>{s, s + n};
diff --git a/sherpa-onnx/csrc/sherpa-onnx-offline-tts.cc b/sherpa-onnx/csrc/sherpa-onnx-offline-tts.cc
index aeab20ff..6f5a1225 100644
--- a/sherpa-onnx/csrc/sherpa-onnx-offline-tts.cc
+++ b/sherpa-onnx/csrc/sherpa-onnx-offline-tts.cc
@@ -9,9 +9,8 @@
 #include "sherpa-onnx/csrc/parse-options.h"
 #include "sherpa-onnx/csrc/wave-writer.h"
 
-void audioCallback(const float *samples, int32_t n, float progress)
-{
-	printf( "sample=%d, progress=%f\n", n, progress );
+void audioCallback(const float *samples, int32_t n, float progress) {
+  printf("sample=%d, progress=%f\n", n, progress);
 }
 
 int main(int32_t argc, char *argv[]) {
diff --git a/sherpa-onnx/csrc/speaker-embedding-manager.cc b/sherpa-onnx/csrc/speaker-embedding-manager.cc
index fd60f4fd..e067a2eb 100644
--- a/sherpa-onnx/csrc/speaker-embedding-manager.cc
+++ b/sherpa-onnx/csrc/speaker-embedding-manager.cc
@@ -93,7 +93,7 @@ class SpeakerEmbeddingManager::Impl {
     int32_t num_rows = embedding_matrix_.rows();
 
     if (row_idx < num_rows - 1) {
-      embedding_matrix_.block(row_idx, 0, num_rows - -1 - row_idx, dim_) =
+      embedding_matrix_.block(row_idx, 0, num_rows - 1 - row_idx, dim_) =
           embedding_matrix_.bottomRows(num_rows - 1 - row_idx);
     }
 
diff --git a/sherpa-onnx/jni/jni.cc b/sherpa-onnx/jni/jni.cc
index 5d874bc6..281fd4ee 100644
--- a/sherpa-onnx/jni/jni.cc
+++ b/sherpa-onnx/jni/jni.cc
@@ -795,9 +795,10 @@ class SherpaOnnxOfflineTts {
   explicit SherpaOnnxOfflineTts(const OfflineTtsConfig &config)
       : tts_(config) {}
 
-  GeneratedAudio Generate(
-      const std::string &text, int64_t sid = 0, float speed = 1.0,
-      std::function<void(const float *, int32_t, float)> callback = nullptr) const {
+  GeneratedAudio Generate(const std::string &text, int64_t sid = 0,
+                          float speed = 1.0,
+                          std::function<void(const float *, int32_t, float)>
+                              callback = nullptr) const {
     return tts_.Generate(text, sid, speed, callback);
   }
 
diff --git a/sherpa-onnx/python/csrc/offline-tts.cc b/sherpa-onnx/python/csrc/offline-tts.cc
index 82006330..ff31ded9 100644
--- a/sherpa-onnx/python/csrc/offline-tts.cc
+++ b/sherpa-onnx/python/csrc/offline-tts.cc
@@ -55,14 +55,16 @@ void PybindOfflineTts(py::module *m) {
       .def(
           "generate",
           [](const PyClass &self, const std::string &text, int64_t sid,
-             float speed, std::function<void(py::array_t<float>, float)> callback)
+             float speed,
+             std::function<void(py::array_t<float>, float)> callback)
               -> GeneratedAudio {
             if (!callback) {
               return self.Generate(text, sid, speed);
             }
 
-            std::function<void(const float *, int32_t, float)> callback_wrapper =
-                [callback](const float *samples, int32_t n, float progress) {
+            std::function<void(const float *, int32_t, float)>
+                callback_wrapper = [callback](const float *samples, int32_t n,
+                                              float progress) {
                   // CAUTION(fangjun): we have to copy samples since it is
                   // freed once the call back returns.