diff --git a/CMakeLists.txt b/CMakeLists.txt
index b785a8e6..f9e255dd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -45,6 +45,7 @@ option(WEBP_BUILD_LIBWEBPMUX "Build the libwebpmux library." ON)
 option(WEBP_BUILD_WEBPMUX "Build the webpmux command line tool." ON)
 option(WEBP_BUILD_EXTRAS "Build extras." ON)
 option(WEBP_BUILD_WEBP_JS "Emscripten build of webp.js." OFF)
+option(WEBP_BUILD_FUZZTEST "Build the fuzztest tests." OFF)
 option(WEBP_USE_THREAD "Enable threading support" ON)
 option(WEBP_NEAR_LOSSLESS "Enable near-lossless encoding" ON)
 option(WEBP_ENABLE_SWAP_16BIT_CSP "Enable byte swap for 16 bit colorspaces."
@@ -375,9 +376,11 @@ if(XCODE)
 endif()
 target_link_libraries(webpdecoder ${WEBP_DEP_LIBRARIES})
 target_include_directories(
-  webpdecoder PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
-  INTERFACE $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}>
-            $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
+  webpdecoder
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR} ${CMAKE_CURRENT_SOURCE_DIR}
+  INTERFACE
+    "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR};${CMAKE_CURRENT_BINARY_DIR}>"
+    $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
 set_target_properties(
   webpdecoder
   PROPERTIES PUBLIC_HEADER "${CMAKE_CURRENT_SOURCE_DIR}/src/webp/decode.h;\
@@ -771,6 +774,10 @@ if(WEBP_BUILD_ANIM_UTILS)
   target_include_directories(anim_dump PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/src)
 endif()
 
+if(WEBP_BUILD_FUZZTEST)
+  add_subdirectory(tests/fuzzer)
+endif()
+
 # Install the different headers and libraries.
 install(
   TARGETS ${INSTALLED_LIBRARIES}
diff --git a/tests/README.md b/tests/README.md
index 91daba26..60180c95 100644
--- a/tests/README.md
+++ b/tests/README.md
@@ -11,8 +11,9 @@ https://chromium.googlesource.com/webm/libwebp-test-data
 Follow the [build instructions](../doc/building.md) for libwebp, optionally
 adding build flags for various sanitizers (e.g., -fsanitize=address).
 
-`fuzzer/makefile.unix` can then be used to compile the fuzzer targets:
+`-DWEBP_BUILD_FUZZTEST=ON` can then be used to compile the fuzzer targets:
 
 ```shell
-$ make -C fuzzer -f makefile.unix
+$ cmake -B ./build -S . -DWEBP_BUILD_FUZZTEST=ON
+$ make -C build
 ```
diff --git a/tests/fuzzer/CMakeLists.txt b/tests/fuzzer/CMakeLists.txt
new file mode 100644
index 00000000..dbd5d030
--- /dev/null
+++ b/tests/fuzzer/CMakeLists.txt
@@ -0,0 +1,61 @@
+#  Copyright (c) 2024 Google LLC
+#
+#  Use of this source code is governed by a BSD-style license
+#  that can be found in the LICENSE file in the root of the source
+#  tree. An additional intellectual property rights grant can be found
+#  in the file PATENTS.  All contributing project authors may
+#  be found in the AUTHORS file in the root of the source tree.
+
+# Adds a fuzztest from file TEST_NAME.cc located in the gtest folder. Extra
+# arguments are considered as extra source files.
+
+if(CMAKE_VERSION VERSION_LESS "3.19.0")
+  return()
+endif()
+
+macro(add_webp_fuzztest TEST_NAME)
+  add_executable(${TEST_NAME} ${TEST_NAME}.cc)
+  # FuzzTest bundles GoogleTest so no need to link to gtest libraries.
+  target_link_libraries(${TEST_NAME} PRIVATE fuzz_utils webp ${ARGN})
+  link_fuzztest(${TEST_NAME})
+  add_test(NAME ${TEST_NAME} COMMAND ${TEST_NAME})
+  set_property(
+    TEST ${TEST_NAME}
+    PROPERTY ENVIRONMENT "TEST_DATA_DIRS=${CMAKE_CURRENT_SOURCE_DIR}/data/")
+endmacro()
+
+enable_language(CXX)
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+include(FetchContent)
+
+set(FETCHCONTENT_QUIET FALSE)
+set(fuzztest_SOURCE_DIR ${CMAKE_BINARY_DIR}/_deps/fuzztest-src)
+FetchContent_Declare(
+  fuzztest
+  GIT_REPOSITORY https://github.com/google/fuzztest.git
+  GIT_TAG a40caf40aaf621dd0e04f9d8b47d1153fd2682d2
+  GIT_PROGRESS TRUE
+  PATCH_COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/patch.sh)
+
+FetchContent_MakeAvailable(fuzztest)
+
+fuzztest_setup_fuzzing_flags()
+
+add_library(fuzz_utils fuzz_utils.h fuzz_utils.cc img_alpha.h img_grid.h
+                       img_peak.h)
+target_link_libraries(fuzz_utils PUBLIC webpdecoder)
+link_fuzztest(fuzz_utils)
+
+add_webp_fuzztest(advanced_api_fuzzer)
+add_webp_fuzztest(enc_dec_fuzzer)
+add_webp_fuzztest(huffman_fuzzer)
+add_webp_fuzztest(simple_api_fuzzer)
+
+if(WEBP_BUILD_LIBWEBPMUX)
+  add_webp_fuzztest(animation_api_fuzzer webpdemux)
+  add_webp_fuzztest(animdecoder_fuzzer imageioutil webpdemux)
+  add_webp_fuzztest(animencoder_fuzzer libwebpmux)
+  add_webp_fuzztest(mux_demux_api_fuzzer libwebpmux webpdemux)
+endif()
diff --git a/tests/fuzzer/advanced_api_fuzzer.c b/tests/fuzzer/advanced_api_fuzzer.cc
similarity index 66%
rename from tests/fuzzer/advanced_api_fuzzer.c
rename to tests/fuzzer/advanced_api_fuzzer.cc
index 22c689bb..5d24af81 100644
--- a/tests/fuzzer/advanced_api_fuzzer.c
+++ b/tests/fuzzer/advanced_api_fuzzer.cc
@@ -14,54 +14,59 @@
 //
 ////////////////////////////////////////////////////////////////////////////////
 
-#include <stdint.h>
-#include <string.h>
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <string_view>
 
 #include "./fuzz_utils.h"
 #include "src/utils/rescaler_utils.h"
 #include "src/webp/decode.h"
 
-int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
+namespace {
+
+void AdvancedApiTest(std::string_view blob, uint8_t factor_u8, bool flip,
+                     bool bypass_filtering, bool no_fancy_upsampling,
+                     bool use_threads, bool use_cropping, bool use_scaling,
+                     bool use_dithering, int colorspace, bool incremental) {
   WebPDecoderConfig config;
-  if (!WebPInitDecoderConfig(&config)) return 0;
-  if (WebPGetFeatures(data, size, &config.input) != VP8_STATUS_OK) return 0;
-  if ((size_t)config.input.width * config.input.height > kFuzzPxLimit) return 0;
+  if (!WebPInitDecoderConfig(&config)) return;
+  const uint8_t* const data = reinterpret_cast<const uint8_t*>(blob.data());
+  const size_t size = blob.size();
+  if (WebPGetFeatures(data, size, &config.input) != VP8_STATUS_OK) return;
+  if ((size_t)config.input.width * config.input.height >
+      fuzz_utils::kFuzzPxLimit) {
+    return;
+  }
 
   // Using two independent criteria ensures that all combinations of options
   // can reach each path at the decoding stage, with meaningful differences.
 
-  const uint8_t value = FuzzHash(data, size);
-  const float factor = value / 255.f;  // 0-1
+  const uint8_t value = fuzz_utils::FuzzHash(data, size);
+  const float factor = factor_u8 / 255.f;  // 0-1
 
-  config.options.flip = value & 1;
-  config.options.bypass_filtering = value & 2;
-  config.options.no_fancy_upsampling = value & 4;
-  config.options.use_threads = value & 8;
-  if (size & 1) {
+  config.options.flip = flip;
+  config.options.bypass_filtering = bypass_filtering;
+  config.options.no_fancy_upsampling = no_fancy_upsampling;
+  config.options.use_threads = use_threads;
+  if (use_cropping) {
     config.options.use_cropping = 1;
     config.options.crop_width = (int)(config.input.width * (1 - factor));
     config.options.crop_height = (int)(config.input.height * (1 - factor));
     config.options.crop_left = config.input.width - config.options.crop_width;
     config.options.crop_top = config.input.height - config.options.crop_height;
   }
-  if (size & 2) {
+  if (use_dithering) {
     int strength = (int)(factor * 100);
     config.options.dithering_strength = strength;
     config.options.alpha_dithering_strength = 100 - strength;
   }
-  if (size & 4) {
+  if (use_scaling) {
     config.options.use_scaling = 1;
     config.options.scaled_width = (int)(config.input.width * factor * 2);
     config.options.scaled_height = (int)(config.input.height * factor * 2);
   }
-
-#if defined(WEBP_REDUCE_CSP)
-  config.output.colorspace = (value & 1)
-                                 ? ((value & 2) ? MODE_RGBA : MODE_BGRA)
-                                 : ((value & 2) ? MODE_rgbA : MODE_bgrA);
-#else
-  config.output.colorspace = (WEBP_CSP_MODE)(value % MODE_LAST);
-#endif  // WEBP_REDUCE_CSP
+  config.output.colorspace = static_cast<WEBP_CSP_MODE>(colorspace);
 
   for (int i = 0; i < 2; ++i) {
     if (i == 1) {
@@ -80,7 +85,7 @@ int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
         if (WebPRescalerGetScaledDimensions(config.input.width,
                                             config.input.height, &scaled_width,
                                             &scaled_height)) {
-          size_t fuzz_px_limit = kFuzzPxLimit;
+          size_t fuzz_px_limit = fuzz_utils::kFuzzPxLimit;
           if (scaled_width != config.input.width ||
               scaled_height != config.input.height) {
             // Using the WebPRescalerImport internally can significantly slow
@@ -92,18 +97,18 @@ int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
           // very wide input image to a very tall canvas can be as slow as
           // decoding a huge number of pixels. Avoid timeouts due to these.
           const uint64_t max_num_operations =
-              (uint64_t)Max(scaled_width, config.input.width) *
-              Max(scaled_height, config.input.height);
+              (uint64_t)std::max(scaled_width, config.input.width) *
+              std::max(scaled_height, config.input.height);
           if (max_num_operations > fuzz_px_limit) {
             break;
           }
         }
       }
     }
-    if (size % 3) {
+    if (incremental) {
       // Decodes incrementally in chunks of increasing size.
       WebPIDecoder* idec = WebPIDecode(NULL, 0, &config);
-      if (!idec) return 0;
+      if (!idec) return;
       VP8StatusCode status;
       if (size & 8) {
         size_t available_size = value + 1;
@@ -135,5 +140,28 @@ int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
 
     WebPFreeDecBuffer(&config.output);
   }
-  return 0;
 }
+
+}  // namespace
+
+FUZZ_TEST(AdvancedApi, AdvancedApiTest)
+    .WithDomains(
+        fuzztest::String()
+            .WithMaxSize(fuzz_utils::kMaxWebPFileSize + 1),
+        /*factor_u8=*/fuzztest::Arbitrary<uint8_t>(),
+        /*flip=*/fuzztest::Arbitrary<bool>(),
+        /*bypass_filtering=*/fuzztest::Arbitrary<bool>(),
+        /*no_fancy_upsampling=*/fuzztest::Arbitrary<bool>(),
+        /*use_threads=*/fuzztest::Arbitrary<bool>(),
+        /*use_cropping=*/fuzztest::Arbitrary<bool>(),
+        /*use_scaling=*/fuzztest::Arbitrary<bool>(),
+        /*use_dithering=*/fuzztest::Arbitrary<bool>(),
+#if defined(WEBP_REDUCE_CSP)
+        fuzztest::ElementOf<int>({static_cast<int>(MODE_RGBA),
+                                  static_cast<int>(MODE_BGRA),
+                                  static_cast<int>(MODE_rgbA),
+                                  static_cast<int>(MODE_bgrA)}),
+#else
+        fuzztest::InRange<int>(0, static_cast<int>(MODE_LAST) - 1),
+#endif
+        /*incremental=*/fuzztest::Arbitrary<bool>());
diff --git a/tests/fuzzer/animation_api_fuzzer.c b/tests/fuzzer/animation_api_fuzzer.cc
similarity index 60%
rename from tests/fuzzer/animation_api_fuzzer.c
rename to tests/fuzzer/animation_api_fuzzer.cc
index 187ed24e..efe0e1db 100644
--- a/tests/fuzzer/animation_api_fuzzer.c
+++ b/tests/fuzzer/animation_api_fuzzer.cc
@@ -14,37 +14,46 @@
 //
 ////////////////////////////////////////////////////////////////////////////////
 
+#include <cstddef>
+#include <cstdint>
+#include <string_view>
+
 #include "./fuzz_utils.h"
 #include "src/webp/decode.h"
 #include "src/webp/demux.h"
 #include "src/webp/mux_types.h"
 
-int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
+namespace {
+
+void AnimationApiTest(std::string_view blob, bool use_threads,
+                      WEBP_CSP_MODE color_mode) {
+  const size_t size = blob.size();
   WebPData webp_data;
   WebPDataInit(&webp_data);
   webp_data.size = size;
-  webp_data.bytes = data;
+  webp_data.bytes = reinterpret_cast<const uint8_t*>(blob.data());
 
   // WebPAnimDecoderNew uses WebPDemux internally to calloc canvas size.
   WebPDemuxer* const demux = WebPDemux(&webp_data);
-  if (!demux) return 0;
+  if (!demux) return;
   const uint32_t cw = WebPDemuxGetI(demux, WEBP_FF_CANVAS_WIDTH);
   const uint32_t ch = WebPDemuxGetI(demux, WEBP_FF_CANVAS_HEIGHT);
-  if ((size_t)cw * ch > kFuzzPxLimit) {
+  if ((size_t)cw * ch > fuzz_utils::kFuzzPxLimit) {
     WebPDemuxDelete(demux);
-    return 0;
+    return;
   }
 
   // In addition to canvas size, check each frame separately.
   WebPIterator iter;
-  for (int i = 0; i < kFuzzFrameLimit; i++) {
+  for (int i = 0; i < fuzz_utils::kFuzzFrameLimit; i++) {
     if (!WebPDemuxGetFrame(demux, i + 1, &iter)) break;
     int w, h;
     if (WebPGetInfo(iter.fragment.bytes, iter.fragment.size, &w, &h)) {
-      if ((size_t)w * h > kFuzzPxLimit) {  // image size of the frame payload
+      if ((size_t)w * h >
+          fuzz_utils::kFuzzPxLimit) {  // image size of the frame payload
         WebPDemuxReleaseIterator(&iter);
         WebPDemuxDelete(demux);
-        return 0;
+        return;
       }
     }
   }
@@ -53,26 +62,30 @@ int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
   WebPDemuxDelete(demux);
 
   WebPAnimDecoderOptions dec_options;
-  if (!WebPAnimDecoderOptionsInit(&dec_options)) return 0;
+  if (!WebPAnimDecoderOptionsInit(&dec_options)) return;
 
-  dec_options.use_threads = size & 1;
-  // Animations only support 4 (of 12) modes.
-  dec_options.color_mode = (WEBP_CSP_MODE)(size % MODE_LAST);
-  if (dec_options.color_mode != MODE_BGRA &&
-      dec_options.color_mode != MODE_rgbA &&
-      dec_options.color_mode != MODE_bgrA) {
-    dec_options.color_mode = MODE_RGBA;
-  }
+  dec_options.use_threads = use_threads;
+  dec_options.color_mode = color_mode;
 
   WebPAnimDecoder* dec = WebPAnimDecoderNew(&webp_data, &dec_options);
-  if (!dec) return 0;
+  if (!dec) return;
 
-  for (int i = 0; i < kFuzzFrameLimit; i++) {
+  for (int i = 0; i < fuzz_utils::kFuzzFrameLimit; i++) {
     uint8_t* buf;
     int timestamp;
     if (!WebPAnimDecoderGetNext(dec, &buf, &timestamp)) break;
   }
 
   WebPAnimDecoderDelete(dec);
-  return 0;
 }
+
+}  // namespace
+
+FUZZ_TEST(AnimationApi, AnimationApiTest)
+    .WithDomains(
+        fuzztest::String()
+            .WithMaxSize(fuzz_utils::kMaxWebPFileSize + 1),
+        /*use_threads=*/fuzztest::Arbitrary<bool>(),
+        // Animations only support 4 (out of 12) modes.
+        fuzztest::ElementOf<WEBP_CSP_MODE>({MODE_RGBA, MODE_BGRA, MODE_rgbA,
+                                            MODE_bgrA}));
diff --git a/tests/fuzzer/animdecoder_fuzzer.cc b/tests/fuzzer/animdecoder_fuzzer.cc
index c3ea4758..9826a644 100644
--- a/tests/fuzzer/animdecoder_fuzzer.cc
+++ b/tests/fuzzer/animdecoder_fuzzer.cc
@@ -16,13 +16,20 @@
 
 #include <cstddef>
 #include <cstdint>
+#include <string_view>
 
+#include "./fuzz_utils.h"
 #include "imageio/imageio_util.h"
 #include "src/webp/decode.h"
 #include "src/webp/demux.h"
 #include "src/webp/mux_types.h"
 
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+namespace {
+
+void AnimDecoderTest(std::string_view blob) {
+  const uint8_t* const data = reinterpret_cast<const uint8_t*>(blob.data());
+  const size_t size = blob.size();
+
   // WebPAnimDecoderGetInfo() is too late to check the canvas size as
   // WebPAnimDecoderNew() will handle the allocations.
   const size_t kMaxNumBytes = 2684354560;  // RSS (resident set size) limit.
@@ -34,14 +41,14 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
                                              features.height) ||
         static_cast<size_t>(features.width) * features.height >
             kMaxNumPixelsSafe) {
-      return 0;
+      return;
     }
   }
 
   // decode everything as an animation
   WebPData webp_data = {data, size};
   WebPAnimDecoder* const dec = WebPAnimDecoderNew(&webp_data, nullptr);
-  if (dec == nullptr) return 0;
+  if (dec == nullptr) return;
 
   WebPAnimInfo info;
   if (!WebPAnimDecoderGetInfo(dec, &info)) goto End;
@@ -57,5 +64,11 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   }
 End:
   WebPAnimDecoderDelete(dec);
-  return 0;
 }
+
+}  // namespace
+
+FUZZ_TEST(AnimDecoder, AnimDecoderTest)
+    .WithDomains(
+        fuzztest::String()
+            .WithMaxSize(fuzz_utils::kMaxWebPFileSize + 1));
diff --git a/tests/fuzzer/animencoder_fuzzer.cc b/tests/fuzzer/animencoder_fuzzer.cc
index ef6ec1e4..85b603a4 100644
--- a/tests/fuzzer/animencoder_fuzzer.cc
+++ b/tests/fuzzer/animencoder_fuzzer.cc
@@ -14,21 +14,48 @@
 //
 ////////////////////////////////////////////////////////////////////////////////
 
-#include <stdio.h>
-#include <stdlib.h>
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <string_view>
+#include <utility>
+#include <vector>
 
 #include "./fuzz_utils.h"
+#include "src/dsp/cpu.h"
 #include "src/webp/encode.h"
 #include "src/webp/mux.h"
+#include "src/webp/mux_types.h"
 
 namespace {
 
-const VP8CPUInfo default_VP8GetCPUInfo = VP8GetCPUInfo;
+const VP8CPUInfo default_VP8GetCPUInfo = fuzz_utils::VP8GetCPUInfo;
+
+struct FrameConfig {
+  int use_argb;
+  int timestamp;
+  WebPConfig webp_config;
+  fuzz_utils::CropOrScaleParams crop_or_scale_params;
+  int source_image_index;
+};
+
+auto ArbitraryKMinKMax() {
+  return fuzztest::FlatMap(
+      [](int kmax) {
+        const int min_kmin = (kmax > 1) ? (kmax / 2) : 0;
+        const int max_kmin = (kmax > 1) ? (kmax - 1) : 0;
+        return fuzztest::PairOf(fuzztest::InRange(min_kmin, max_kmin),
+                                fuzztest::Just(kmax));
+      },
+      fuzztest::InRange(0, 15));
+}
 
 int AddFrame(WebPAnimEncoder** const enc,
              const WebPAnimEncoderOptions& anim_config, int* const width,
-             int* const height, int timestamp_ms, const uint8_t data[],
-             size_t size, uint32_t* const bit_pos) {
+             int* const height, int timestamp_ms,
+             const FrameConfig& frame_config, const uint8_t data[], size_t size,
+             uint32_t* const bit_pos) {
   if (enc == nullptr || width == nullptr || height == nullptr) {
     fprintf(stderr, "NULL parameters.\n");
     if (enc != nullptr) WebPAnimEncoderDelete(*enc);
@@ -36,27 +63,12 @@ int AddFrame(WebPAnimEncoder** const enc,
   }
 
   // Init the source picture.
-  WebPPicture pic;
-  if (!WebPPictureInit(&pic)) {
-    fprintf(stderr, "WebPPictureInit failed.\n");
-    WebPAnimEncoderDelete(*enc);
-    abort();
-  }
-  pic.use_argb = Extract(1, data, size, bit_pos);
-
-  // Read the source picture.
-  if (!ExtractSourcePicture(&pic, data, size, bit_pos)) {
-    const WebPEncodingError error_code = pic.error_code;
-    WebPAnimEncoderDelete(*enc);
-    WebPPictureFree(&pic);
-    if (error_code == VP8_ENC_ERROR_OUT_OF_MEMORY) return 0;
-    fprintf(stderr, "Can't read input image. Error code: %d\n", error_code);
-    abort();
-  }
+  WebPPicture pic = fuzz_utils::GetSourcePicture(
+      frame_config.source_image_index, frame_config.use_argb);
 
   // Crop and scale.
   if (*enc == nullptr) {  // First frame will set canvas width and height.
-    if (!ExtractAndCropOrScale(&pic, data, size, bit_pos)) {
+    if (!fuzz_utils::CropOrScale(&pic, frame_config.crop_or_scale_params)) {
       const WebPEncodingError error_code = pic.error_code;
       WebPPictureFree(&pic);
       if (error_code == VP8_ENC_ERROR_OUT_OF_MEMORY) return 0;
@@ -89,13 +101,7 @@ int AddFrame(WebPAnimEncoder** const enc,
   }
 
   // Create frame encoding config.
-  WebPConfig config;
-  if (!ExtractWebPConfig(&config, data, size, bit_pos)) {
-    fprintf(stderr, "ExtractWebPConfig failed.\n");
-    WebPAnimEncoderDelete(*enc);
-    WebPPictureFree(&pic);
-    abort();
-  }
+  WebPConfig config = frame_config.webp_config;
   // Skip slow settings on big images, it's likely to timeout.
   if (pic.width * pic.height > 32 * 32) {
     config.method = (config.method > 4) ? 4 : config.method;
@@ -125,14 +131,17 @@ int AddFrame(WebPAnimEncoder** const enc,
   return 1;
 }
 
-}  // namespace
-
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
+void AnimEncoderTest(std::string_view blob, bool minimize_size,
+                     std::pair<int, int> kmin_kmax, bool allow_mixed,
+                     const std::vector<FrameConfig>& frame_configs,
+                     int optimization_index) {
   WebPAnimEncoder* enc = nullptr;
   int width = 0, height = 0, timestamp_ms = 0;
   uint32_t bit_pos = 0;
+  const uint8_t* const data = reinterpret_cast<const uint8_t*>(blob.data());
+  const size_t size = blob.size();
 
-  ExtractAndDisableOptimizations(default_VP8GetCPUInfo, data, size, &bit_pos);
+  fuzz_utils::SetOptimization(default_VP8GetCPUInfo, optimization_index);
 
   // Extract a configuration from the packed bits.
   WebPAnimEncoderOptions anim_config;
@@ -140,26 +149,20 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
     fprintf(stderr, "WebPAnimEncoderOptionsInit failed.\n");
     abort();
   }
-  anim_config.minimize_size = Extract(1, data, size, &bit_pos);
-  anim_config.kmax = Extract(15, data, size, &bit_pos);
-  const int min_kmin = (anim_config.kmax > 1) ? (anim_config.kmax / 2) : 0;
-  const int max_kmin = (anim_config.kmax > 1) ? (anim_config.kmax - 1) : 0;
-  anim_config.kmin =
-      min_kmin + Extract((uint32_t)(max_kmin - min_kmin), data, size, &bit_pos);
-  anim_config.allow_mixed = Extract(1, data, size, &bit_pos);
+  anim_config.minimize_size = minimize_size;
+  anim_config.kmin = kmin_kmax.first;
+  anim_config.kmax = kmin_kmax.second;
+  anim_config.allow_mixed = allow_mixed;
   anim_config.verbose = 0;
 
-  const int nb_frames = 1 + Extract(15, data, size, &bit_pos);
-
   // For each frame.
-  for (int i = 0; i < nb_frames; ++i) {
-    if (!AddFrame(&enc, anim_config, &width, &height, timestamp_ms, data, size,
-                  &bit_pos)) {
-      return 0;
+  for (const FrameConfig& frame_config : frame_configs) {
+    if (!AddFrame(&enc, anim_config, &width, &height, timestamp_ms,
+                  frame_config, data, size, &bit_pos)) {
+      return;
     }
 
-    timestamp_ms += (1 << (2 + Extract(15, data, size, &bit_pos))) +
-                    Extract(1, data, size, &bit_pos);  // [1..131073], arbitrary
+    timestamp_ms += frame_config.timestamp;
   }
 
   // Assemble.
@@ -184,5 +187,22 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
 
   WebPAnimEncoderDelete(enc);
   WebPDataClear(&webp_data);
-  return 0;
 }
+
+}  // namespace
+
+FUZZ_TEST(AnimEncoder, AnimEncoderTest)
+    .WithDomains(
+        fuzztest::String(),
+        /*minimize_size=*/fuzztest::Arbitrary<bool>(), ArbitraryKMinKMax(),
+        /*allow_mixed=*/fuzztest::Arbitrary<bool>(),
+        fuzztest::VectorOf(
+            fuzztest::StructOf<FrameConfig>(
+                fuzztest::InRange<int>(0, 1), fuzztest::InRange<int>(0, 131073),
+                fuzz_utils::ArbitraryWebPConfig(),
+                fuzz_utils::ArbitraryCropOrScaleParams(),
+                fuzztest::InRange<int>(0, fuzz_utils::kNumSourceImages - 1)))
+            .WithMinSize(1)
+            .WithMaxSize(15),
+        /*optimization_index=*/
+        fuzztest::InRange<uint32_t>(0, fuzz_utils::kMaxOptimizationIndex));
diff --git a/tests/fuzzer/enc_dec_fuzzer.cc b/tests/fuzzer/enc_dec_fuzzer.cc
index c5d46ae0..c6769aef 100644
--- a/tests/fuzzer/enc_dec_fuzzer.cc
+++ b/tests/fuzzer/enc_dec_fuzzer.cc
@@ -14,57 +14,37 @@
 //
 ////////////////////////////////////////////////////////////////////////////////
 
-#include <stdio.h>
-#include <stdlib.h>
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
 
 #include "./fuzz_utils.h"
+#include "src/dsp/cpu.h"
 #include "src/webp/decode.h"
 #include "src/webp/encode.h"
 
 namespace {
 
-const VP8CPUInfo default_VP8GetCPUInfo = VP8GetCPUInfo;
+const VP8CPUInfo default_VP8GetCPUInfo = fuzz_utils::VP8GetCPUInfo;
 
-}  // namespace
-
-extern "C" int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
-  uint32_t bit_pos = 0;
-
-  ExtractAndDisableOptimizations(default_VP8GetCPUInfo, data, size, &bit_pos);
+void EncDecTest(bool use_argb, int source_image_index, WebPConfig config,
+                int optimization_index,
+                const fuzz_utils::CropOrScaleParams& crop_or_scale_params) {
+  fuzz_utils::SetOptimization(default_VP8GetCPUInfo, optimization_index);
 
   // Init the source picture.
-  WebPPicture pic;
-  if (!WebPPictureInit(&pic)) {
-    fprintf(stderr, "WebPPictureInit failed.\n");
-    abort();
-  }
-  pic.use_argb = Extract(1, data, size, &bit_pos);
-
-  // Read the source picture.
-  if (!ExtractSourcePicture(&pic, data, size, &bit_pos)) {
-    const WebPEncodingError error_code = pic.error_code;
-    WebPPictureFree(&pic);
-    if (error_code == VP8_ENC_ERROR_OUT_OF_MEMORY) return 0;
-    fprintf(stderr, "Can't read input image. Error code: %d\n", error_code);
-    abort();
-  }
+  WebPPicture pic = fuzz_utils::GetSourcePicture(source_image_index, use_argb);
 
   // Crop and scale.
-  if (!ExtractAndCropOrScale(&pic, data, size, &bit_pos)) {
+  if (!fuzz_utils::CropOrScale(&pic, crop_or_scale_params)) {
     const WebPEncodingError error_code = pic.error_code;
     WebPPictureFree(&pic);
-    if (error_code == VP8_ENC_ERROR_OUT_OF_MEMORY) return 0;
+    if (error_code == VP8_ENC_ERROR_OUT_OF_MEMORY) return;
     fprintf(stderr, "ExtractAndCropOrScale failed. Error code: %d\n",
             error_code);
     abort();
   }
 
-  // Extract a configuration from the packed bits.
-  WebPConfig config;
-  if (!ExtractWebPConfig(&config, data, size, &bit_pos)) {
-    fprintf(stderr, "ExtractWebPConfig failed.\n");
-    abort();
-  }
   // Skip slow settings on big images, it's likely to timeout.
   if (pic.width * pic.height > 32 * 32) {
     if (config.lossless) {
@@ -93,7 +73,7 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
     WebPPictureFree(&pic);
     if (error_code == VP8_ENC_ERROR_OUT_OF_MEMORY ||
         error_code == VP8_ENC_ERROR_BAD_WRITE) {
-      return 0;
+      return;
     }
     fprintf(stderr, "WebPEncode failed. Error code: %d\n", error_code);
     abort();
@@ -157,5 +137,16 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
   WebPFreeDecBuffer(&dec_config.output);
   WebPMemoryWriterClear(&memory_writer);
   WebPPictureFree(&pic);
-  return 0;
 }
+
+}  // namespace
+
+FUZZ_TEST(EncDec, EncDecTest)
+    .WithDomains(/*use_argb=*/fuzztest::Arbitrary<bool>(),
+                 /*source_image_index=*/
+                 fuzztest::InRange<int>(0, fuzz_utils::kNumSourceImages - 1),
+                 fuzz_utils::ArbitraryWebPConfig(),
+                 /*optimization_index=*/
+                 fuzztest::InRange<uint32_t>(0,
+                                             fuzz_utils::kMaxOptimizationIndex),
+                 fuzz_utils::ArbitraryCropOrScaleParams());
diff --git a/tests/fuzzer/fuzz_utils.cc b/tests/fuzzer/fuzz_utils.cc
new file mode 100644
index 00000000..72fd2fee
--- /dev/null
+++ b/tests/fuzzer/fuzz_utils.cc
@@ -0,0 +1,201 @@
+// Copyright 2024 Google LLC
+//
+// 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.
+//
+////////////////////////////////////////////////////////////////////////////////
+
+#include "./fuzz_utils.h"
+
+#include <algorithm>
+#include <cassert>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <fstream>
+#include <iostream>
+#include <string>
+#include <string_view>
+#include <tuple>
+#include <vector>
+
+#include "./img_alpha.h"
+#include "./img_grid.h"
+#include "./img_peak.h"
+#include "src/dsp/cpu.h"
+#include "src/webp/decode.h"
+#include "src/webp/encode.h"
+#include "src/webp/types.h"
+
+namespace fuzz_utils {
+
+WebPPicture GetSourcePicture(int image_index, bool use_argb) {
+  WebPPicture pic;
+  if (!WebPPictureInit(&pic)) abort();
+  pic.use_argb = use_argb;
+
+  // Pick a source picture.
+  const int kImagesWidth[] = {kImgAlphaWidth, kImgGridWidth, kImgPeakWidth};
+  const int kImagesHeight[] = {kImgAlphaHeight, kImgGridHeight, kImgPeakHeight};
+  const uint8_t* const image_data = kImagesData[image_index];
+  pic.width = kImagesWidth[image_index];
+  pic.height = kImagesHeight[image_index];
+  pic.argb_stride = pic.width * 4 * sizeof(uint8_t);
+
+  // Read the bytes.
+  if (!WebPPictureImportRGBA(&pic, image_data, pic.argb_stride)) abort();
+  return pic;
+}
+
+//------------------------------------------------------------------------------
+
+int CropOrScale(WebPPicture* const pic, const CropOrScaleParams& params) {
+  if (pic == NULL) return 0;
+#if !defined(WEBP_REDUCE_SIZE)
+  if (params.alter_input) {
+    if (params.crop_or_scale) {
+      const int cropped_width = std::max(1, pic->width / params.width_ratio);
+      const int cropped_height = std::max(1, pic->height / params.height_ratio);
+      const int cropped_left = (pic->width - cropped_width) / params.left_ratio;
+      const int cropped_top = (pic->height - cropped_height) / params.top_ratio;
+      return WebPPictureCrop(pic, cropped_left, cropped_top, cropped_width,
+                             cropped_height);
+    } else {
+      const int scaled_width = 1 + (pic->width * params.width_ratio) / 8;
+      const int scaled_height = 1 + (pic->height * params.height_ratio) / 8;
+      return WebPPictureRescale(pic, scaled_width, scaled_height);
+    }
+  }
+#else   // defined(WEBP_REDUCE_SIZE)
+  (void)data;
+  (void)size;
+  (void)bit_pos;
+#endif  // !defined(WEBP_REDUCE_SIZE)
+  return 1;
+}
+
+extern "C" VP8CPUInfo VP8GetCPUInfo;
+static VP8CPUInfo GetCPUInfo;
+
+static WEBP_INLINE int GetCPUInfoNoSSE41(CPUFeature feature) {
+  if (feature == kSSE4_1 || feature == kAVX) return 0;
+  return GetCPUInfo(feature);
+}
+
+static WEBP_INLINE int GetCPUInfoNoAVX(CPUFeature feature) {
+  if (feature == kAVX) return 0;
+  return GetCPUInfo(feature);
+}
+
+static WEBP_INLINE int GetCPUInfoForceSlowSSSE3(CPUFeature feature) {
+  if (feature == kSlowSSSE3 && GetCPUInfo(kSSE3)) {
+    return 1;  // we have SSE3 -> force SlowSSSE3
+  }
+  return GetCPUInfo(feature);
+}
+
+static WEBP_INLINE int GetCPUInfoOnlyC(CPUFeature feature) {
+  (void)feature;
+  return 0;
+}
+
+void SetOptimization(VP8CPUInfo default_VP8GetCPUInfo, uint32_t index) {
+  assert(index <= kMaxOptimizationIndex);
+  GetCPUInfo = default_VP8GetCPUInfo;
+  const VP8CPUInfo kVP8CPUInfos[kMaxOptimizationIndex + 1] = {
+      GetCPUInfoOnlyC, GetCPUInfoForceSlowSSSE3, GetCPUInfoNoSSE41,
+      GetCPUInfoNoAVX, GetCPUInfo};
+  VP8GetCPUInfo = kVP8CPUInfos[index];
+}
+
+//------------------------------------------------------------------------------
+
+std::vector<std::string> ReadFilesFromDirectory(std::string_view dir) {
+  std::vector<std::tuple<std::string>> tuples =
+      fuzztest::ReadFilesFromDirectory(dir);
+  std::vector<std::string> strings(tuples.size());
+  for (size_t i = 0; i < tuples.size(); ++i) {
+    using std::swap;
+    swap(std::get<0>(tuples[i]), strings[i]);
+  }
+  return strings;
+}
+
+//------------------------------------------------------------------------------
+// The code in this section is copied from
+// https://github.com/webmproject/sjpeg/blob/
+//                1c025b3dbc2246de3e1d7c287970f1a01291800f/src/jpeg_tools.cc#L47
+// (same license as this file).
+
+namespace {
+// Constants below are marker codes defined in JPEG spec
+// ISO/IEC 10918-1 : 1993(E) Table B.1
+// See also: http://www.w3.org/Graphics/JPEG/itu-t81.pdf
+
+#define M_SOF0 0xffc0
+#define M_SOF1 0xffc1
+
+const uint8_t* GetSOFData(const uint8_t* src, int size) {
+  if (src == NULL) return NULL;
+  const uint8_t* const end = src + size - 8;  // 8 bytes of safety, for marker
+  src += 2;                                   // skip M_SOI
+  for (; src < end && *src != 0xff; ++src) {  /* search first 0xff marker */
+  }
+  while (src < end) {
+    const uint32_t marker = static_cast<uint32_t>((src[0] << 8) | src[1]);
+    if (marker == M_SOF0 || marker == M_SOF1) return src;
+    const size_t s = 2 + ((src[2] << 8) | src[3]);
+    src += s;
+  }
+  return NULL;  // No SOF marker found
+}
+
+bool SjpegDimensions(const uint8_t* src0, size_t size, int* width, int* height,
+                     int* is_yuv420) {
+  if (width == NULL || height == NULL) return false;
+  const uint8_t* src = GetSOFData(src0, size);
+  const size_t left_over = size - (src - src0);
+  if (src == NULL || left_over < 8 + 3 * 1) return false;
+  if (height != NULL) *height = (src[5] << 8) | src[6];
+  if (width != NULL) *width = (src[7] << 8) | src[8];
+  if (is_yuv420 != NULL) {
+    const size_t nb_comps = src[9];
+    *is_yuv420 = (nb_comps == 3);
+    if (left_over < 11 + 3 * nb_comps) return false;
+    for (int c = 0; *is_yuv420 && c < 3; ++c) {
+      const int expected_dim = (c == 0 ? 0x22 : 0x11);
+      *is_yuv420 &= (src[11 + c * 3] == expected_dim);
+    }
+  }
+  return true;
+}
+}  // namespace
+
+//------------------------------------------------------------------------------
+
+bool IsImageTooBig(const uint8_t* data, size_t size) {
+  int width, height, components;
+  if (SjpegDimensions(data, size, &width, &height, &components) ||
+      WebPGetInfo(data, size, &width, &height)) {
+    // Look at the number of 8x8px blocks rather than the overall pixel count
+    // when comparing to memory and duration thresholds.
+    const size_t ceiled_width = ((size_t)width + 7) / 8 * 8;
+    const size_t ceiled_height = ((size_t)height + 7) / 8 * 8;
+    // Threshold to avoid out-of-memory and timeout issues.
+    // The threshold is arbitrary but below the fuzzer limit of 2 GB.
+    // The value cannot be 2 GB because of the added memory by MSAN.
+    if (ceiled_width * ceiled_height > kFuzzPxLimit) return true;
+  }
+  return false;
+}
+
+}  // namespace fuzz_utils
diff --git a/tests/fuzzer/fuzz_utils.h b/tests/fuzzer/fuzz_utils.h
index c3fc366d..1d92a077 100644
--- a/tests/fuzzer/fuzz_utils.h
+++ b/tests/fuzzer/fuzz_utils.h
@@ -1,4 +1,4 @@
-// Copyright 2018 Google Inc.
+// Copyright 2018-2024 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -17,14 +17,23 @@
 #ifndef WEBP_TESTS_FUZZER_FUZZ_UTILS_H_
 #define WEBP_TESTS_FUZZER_FUZZ_UTILS_H_
 
-#include <stdint.h>
-#include <stdlib.h>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <optional>
+#include <string>
+#include <string_view>
+#include <utility>
+#include <vector>
 
 #include "./img_alpha.h"
 #include "./img_grid.h"
 #include "./img_peak.h"
-#include "src/dsp/dsp.h"
+#include "src/dsp/cpu.h"
 #include "src/webp/encode.h"
+#include "fuzztest/fuzztest.h"
+
+namespace fuzz_utils {
 
 //------------------------------------------------------------------------------
 // Arbitrary limits to prevent OOM, timeout, or slow execution.
@@ -54,170 +63,139 @@ static WEBP_INLINE uint8_t FuzzHash(const uint8_t* const data, size_t size) {
   return value;
 }
 
-//------------------------------------------------------------------------------
-// Extract an integer in [0, max_value].
-
-static WEBP_INLINE uint32_t Extract(uint32_t max_value,
-                                    const uint8_t data[], size_t size,
-                                    uint32_t* const bit_pos) {
-  uint32_t v = 0;
-  uint32_t range = 1;
-  while (*bit_pos < 8 * size && range <= max_value) {
-    const uint8_t mask = 1u << (*bit_pos & 7);
-    v = (v << 1) | !!(data[*bit_pos >> 3] & mask);
-    range <<= 1;
-    ++*bit_pos;
-  }
-  return v % (max_value + 1);
-}
-
-//------------------------------------------------------------------------------
-// Some functions to override VP8GetCPUInfo and disable some optimizations.
-
 #ifdef __cplusplus
 extern "C" VP8CPUInfo VP8GetCPUInfo;
 #else
 extern VP8CPUInfo VP8GetCPUInfo;
 #endif
-static VP8CPUInfo GetCPUInfo;
-
-static WEBP_INLINE int GetCPUInfoNoSSE41(CPUFeature feature) {
-  if (feature == kSSE4_1 || feature == kAVX) return 0;
-  return GetCPUInfo(feature);
-}
-
-static WEBP_INLINE int GetCPUInfoNoAVX(CPUFeature feature) {
-  if (feature == kAVX) return 0;
-  return GetCPUInfo(feature);
-}
-
-static WEBP_INLINE int GetCPUInfoForceSlowSSSE3(CPUFeature feature) {
-  if (feature == kSlowSSSE3 && GetCPUInfo(kSSE3)) {
-    return 1;  // we have SSE3 -> force SlowSSSE3
-  }
-  return GetCPUInfo(feature);
-}
-
-static WEBP_INLINE int GetCPUInfoOnlyC(CPUFeature feature) {
-  (void)feature;
-  return 0;
-}
-
-static WEBP_INLINE void ExtractAndDisableOptimizations(
-    VP8CPUInfo default_VP8GetCPUInfo, const uint8_t data[], size_t size,
-    uint32_t* const bit_pos) {
-  GetCPUInfo = default_VP8GetCPUInfo;
-  const VP8CPUInfo kVP8CPUInfos[5] = {GetCPUInfoOnlyC, GetCPUInfoForceSlowSSSE3,
-                                      GetCPUInfoNoSSE41, GetCPUInfoNoAVX,
-                                      GetCPUInfo};
-  int VP8GetCPUInfo_index = Extract(4, data, size, bit_pos);
-  VP8GetCPUInfo = kVP8CPUInfos[VP8GetCPUInfo_index];
-}
 
 //------------------------------------------------------------------------------
 
-static WEBP_INLINE int ExtractWebPConfig(WebPConfig* const config,
-                                         const uint8_t data[], size_t size,
-                                         uint32_t* const bit_pos) {
-  if (config == NULL || !WebPConfigInit(config)) return 0;
-  config->lossless = Extract(1, data, size, bit_pos);
-  config->quality = Extract(100, data, size, bit_pos);
-  config->method = Extract(6, data, size, bit_pos);
-  config->image_hint =
-      (WebPImageHint)Extract(WEBP_HINT_LAST - 1, data, size, bit_pos);
-  config->segments = 1 + Extract(3, data, size, bit_pos);
-  config->sns_strength = Extract(100, data, size, bit_pos);
-  config->filter_strength = Extract(100, data, size, bit_pos);
-  config->filter_sharpness = Extract(7, data, size, bit_pos);
-  config->filter_type = Extract(1, data, size, bit_pos);
-  config->autofilter = Extract(1, data, size, bit_pos);
-  config->alpha_compression = Extract(1, data, size, bit_pos);
-  config->alpha_filtering = Extract(2, data, size, bit_pos);
-  config->alpha_quality = Extract(100, data, size, bit_pos);
-  config->pass = 1 + Extract(9, data, size, bit_pos);
-  config->show_compressed = 1;
-  config->preprocessing = Extract(2, data, size, bit_pos);
-  config->partitions = Extract(3, data, size, bit_pos);
-  config->partition_limit = 10 * Extract(10, data, size, bit_pos);
-  config->emulate_jpeg_size = Extract(1, data, size, bit_pos);
-  config->thread_level = Extract(1, data, size, bit_pos);
-  config->low_memory = Extract(1, data, size, bit_pos);
-  config->near_lossless = 20 * Extract(5, data, size, bit_pos);
-  config->exact = Extract(1, data, size, bit_pos);
-  config->use_delta_palette = Extract(1, data, size, bit_pos);
-  config->use_sharp_yuv = Extract(1, data, size, bit_pos);
-  return WebPValidateConfig(config);
+constexpr const uint8_t* kImagesData[] = {kImgAlphaData, kImgGridData,
+                                          kImgPeakData};
+constexpr size_t kNumSourceImages =
+    sizeof(kImagesData) / sizeof(kImagesData[0]);
+
+WebPPicture GetSourcePicture(int image_index, bool use_argb);
+
+static inline auto ArbitraryWebPConfig() {
+  return fuzztest::Map(
+      [](int lossless, int quality, int method, int image_hint, int segments,
+         int sns_strength, int filter_strength, int filter_sharpness,
+         int filter_type, int autofilter, int alpha_compression,
+         int alpha_filtering, int alpha_quality, int pass, int preprocessing,
+         int partitions, int partition_limit, int emulate_jpeg_size,
+         int thread_level, int low_memory, int near_lossless, int exact,
+         int use_delta_palette, int use_sharp_yuv) -> WebPConfig {
+        WebPConfig config;
+        if (!WebPConfigInit(&config)) abort();
+        config.lossless = lossless;
+        config.quality = quality;
+        config.method = method;
+        config.image_hint = (WebPImageHint)image_hint;
+        config.segments = segments;
+        config.sns_strength = sns_strength;
+        config.filter_strength = filter_strength;
+        config.filter_sharpness = filter_sharpness;
+        config.filter_type = filter_type;
+        config.autofilter = autofilter;
+        config.alpha_compression = alpha_compression;
+        config.alpha_filtering = alpha_filtering;
+        config.alpha_quality = alpha_quality;
+        config.pass = pass;
+        config.show_compressed = 1;
+        config.preprocessing = preprocessing;
+        config.partitions = partitions;
+        config.partition_limit = 10 * partition_limit;
+        config.emulate_jpeg_size = emulate_jpeg_size;
+        config.thread_level = thread_level;
+        config.low_memory = low_memory;
+        config.near_lossless = 20 * near_lossless;
+        config.exact = exact;
+        config.use_delta_palette = use_delta_palette;
+        config.use_sharp_yuv = use_sharp_yuv;
+        if (!WebPValidateConfig(&config)) abort();
+        return config;
+      },
+      /*lossless=*/fuzztest::InRange<int>(0, 1),
+      /*quality=*/fuzztest::InRange<int>(0, 100),
+      /*method=*/fuzztest::InRange<int>(0, 6),
+      /*image_hint=*/fuzztest::InRange<int>(0, WEBP_HINT_LAST - 1),
+      /*segments=*/fuzztest::InRange<int>(1, 4),
+      /*sns_strength=*/fuzztest::InRange<int>(0, 100),
+      /*filter_strength=*/fuzztest::InRange<int>(0, 100),
+      /*filter_sharpness=*/fuzztest::InRange<int>(0, 7),
+      /*filter_type=*/fuzztest::InRange<int>(0, 1),
+      /*autofilter=*/fuzztest::InRange<int>(0, 1),
+      /*alpha_compression=*/fuzztest::InRange<int>(0, 1),
+      /*alpha_filtering=*/fuzztest::InRange<int>(0, 2),
+      /*alpha_quality=*/fuzztest::InRange<int>(0, 100),
+      /*pass=*/fuzztest::InRange<int>(1, 10),
+      /*preprocessing=*/fuzztest::InRange<int>(0, 2),
+      /*partitions=*/fuzztest::InRange<int>(0, 3),
+      /*partition_limit=*/fuzztest::InRange<int>(0, 10),
+      /*emulate_jpeg_size=*/fuzztest::InRange<int>(0, 1),
+      /*thread_level=*/fuzztest::InRange<int>(0, 1),
+      /*low_memory=*/fuzztest::InRange<int>(0, 1),
+      /*near_lossless=*/fuzztest::InRange<int>(0, 5),
+      /*exact=*/fuzztest::InRange<int>(0, 1),
+      /*use_delta_palette=*/fuzztest::InRange<int>(0, 1),
+      /*use_sharp_yuv=*/fuzztest::InRange<int>(0, 1));
 }
 
+struct CropOrScaleParams {
+  bool alter_input;
+  bool crop_or_scale;
+  int width_ratio;
+  int height_ratio;
+  int left_ratio;
+  int top_ratio;
+};
+
+static inline auto ArbitraryCropOrScaleParams() {
+  return fuzztest::Map(
+      [](const std::optional<std::pair<int, int>>& width_height_ratio,
+         const std::optional<std::pair<int, int>>& left_top_ratio)
+          -> CropOrScaleParams {
+        CropOrScaleParams params;
+        params.alter_input = width_height_ratio.has_value();
+        if (params.alter_input) {
+          params.width_ratio = width_height_ratio->first;
+          params.height_ratio = width_height_ratio->second;
+          params.crop_or_scale = left_top_ratio.has_value();
+          if (params.crop_or_scale) {
+            params.left_ratio = left_top_ratio->first;
+            params.top_ratio = left_top_ratio->second;
+          }
+        }
+        return params;
+      },
+      fuzztest::OptionalOf(
+          fuzztest::PairOf(fuzztest::InRange(1, 8), fuzztest::InRange(1, 8))),
+      fuzztest::OptionalOf(
+          fuzztest::PairOf(fuzztest::InRange(1, 8), fuzztest::InRange(1, 8))));
+}
+
+// Crops or scales a picture according to the given params.
+int CropOrScale(WebPPicture* pic, const CropOrScaleParams& params);
+
+// Imposes a level of optimization among one of the kMaxOptimizationIndex+1
+// possible values: OnlyC, ForceSlowSSSE3, NoSSE41, NoAVX, default.
+static constexpr uint32_t kMaxOptimizationIndex = 4;
+void SetOptimization(VP8CPUInfo default_VP8GetCPUInfo, uint32_t index);
+
 //------------------------------------------------------------------------------
 
-static WEBP_INLINE int ExtractSourcePicture(WebPPicture* const pic,
-                                            const uint8_t data[], size_t size,
-                                            uint32_t* const bit_pos) {
-  if (pic == NULL) return 0;
+// See https://developers.google.com/speed/webp/docs/riff_container.
+static constexpr size_t kMaxWebPFileSize = (1ull << 32) - 2;  // 4 GiB - 2
 
-  // Pick a source picture.
-  const uint8_t* kImagesData[] = {
-      kImgAlphaData,
-      kImgGridData,
-      kImgPeakData
-  };
-  const int kImagesWidth[] = {
-      kImgAlphaWidth,
-      kImgGridWidth,
-      kImgPeakWidth
-  };
-  const int kImagesHeight[] = {
-      kImgAlphaHeight,
-      kImgGridHeight,
-      kImgPeakHeight
-  };
-  const size_t kNbImages = sizeof(kImagesData) / sizeof(kImagesData[0]);
-  const size_t image_index = Extract(kNbImages - 1, data, size, bit_pos);
-  const uint8_t* const image_data = kImagesData[image_index];
-  pic->width = kImagesWidth[image_index];
-  pic->height = kImagesHeight[image_index];
-  pic->argb_stride = pic->width * 4 * sizeof(uint8_t);
+std::vector<std::string> GetDictionaryFromFiles(
+    const std::vector<std::string_view>& file_paths);
 
-  // Read the bytes.
-  return WebPPictureImportRGBA(pic, image_data, pic->argb_stride);
-}
+// Checks whether the binary blob containing a JPEG or WebP is too big for the
+// fuzzer.
+bool IsImageTooBig(const uint8_t* data, size_t size);
 
-//------------------------------------------------------------------------------
-
-static WEBP_INLINE int Max(int a, int b) { return ((a < b) ? b : a); }
-
-static WEBP_INLINE int ExtractAndCropOrScale(WebPPicture* const pic,
-                                             const uint8_t data[], size_t size,
-                                             uint32_t* const bit_pos) {
-  if (pic == NULL) return 0;
-#if !defined(WEBP_REDUCE_SIZE)
-  const int alter_input = Extract(1, data, size, bit_pos);
-  const int crop_or_scale = Extract(1, data, size, bit_pos);
-  const int width_ratio = 1 + Extract(7, data, size, bit_pos);
-  const int height_ratio = 1 + Extract(7, data, size, bit_pos);
-  if (alter_input) {
-    if (crop_or_scale) {
-      const uint32_t left_ratio = 1 + Extract(7, data, size, bit_pos);
-      const uint32_t top_ratio = 1 + Extract(7, data, size, bit_pos);
-      const int cropped_width = Max(1, pic->width / width_ratio);
-      const int cropped_height = Max(1, pic->height / height_ratio);
-      const int cropped_left = (pic->width - cropped_width) / left_ratio;
-      const int cropped_top = (pic->height - cropped_height) / top_ratio;
-      return WebPPictureCrop(pic, cropped_left, cropped_top, cropped_width,
-                             cropped_height);
-    } else {
-      const int scaled_width = 1 + (pic->width * width_ratio) / 8;
-      const int scaled_height = 1 + (pic->height * height_ratio) / 8;
-      return WebPPictureRescale(pic, scaled_width, scaled_height);
-    }
-  }
-#else   // defined(WEBP_REDUCE_SIZE)
-  (void)data;
-  (void)size;
-  (void)bit_pos;
-#endif  // !defined(WEBP_REDUCE_SIZE)
-  return 1;
-}
+}  // namespace fuzz_utils
 
 #endif  // WEBP_TESTS_FUZZER_FUZZ_UTILS_H_
diff --git a/tests/fuzzer/huffman_fuzzer.c b/tests/fuzzer/huffman_fuzzer.cc
similarity index 75%
rename from tests/fuzzer/huffman_fuzzer.c
rename to tests/fuzzer/huffman_fuzzer.cc
index 03e1fdc4..6d0fbe6d 100644
--- a/tests/fuzzer/huffman_fuzzer.c
+++ b/tests/fuzzer/huffman_fuzzer.cc
@@ -14,22 +14,29 @@
 //
 ////////////////////////////////////////////////////////////////////////////////
 
-#include <stdint.h>
-#include <string.h>
+#include <cstddef>
+#include <cstdint>
+#include <string_view>
 
+#include "./fuzz_utils.h"
 #include "src/dec/vp8li_dec.h"
 #include "src/utils/bit_reader_utils.h"
 #include "src/utils/huffman_utils.h"
 #include "src/utils/utils.h"
 #include "src/webp/format_constants.h"
 
-int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
+namespace {
+
+void HuffmanTest(std::string_view blob) {
+  const uint8_t* const data = reinterpret_cast<const uint8_t*>(blob.data());
+  const size_t size = blob.size();
+
   // Number of bits to initialize data.
   static const int kColorCacheBitsBits = 4;
   // 'num_htree_groups' is contained in the RG channel, hence 16 bits.
   static const int kNumHtreeGroupsBits = 16;
   if (size * sizeof(*data) < kColorCacheBitsBits + kNumHtreeGroupsBits) {
-    return 0;
+    return;
   }
 
   // A non-NULL mapping brings minor changes that are tested by the normal
@@ -39,27 +46,32 @@ int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
   memset(&huffman_tables, 0, sizeof(huffman_tables));
   HTreeGroup* htree_groups = NULL;
 
+  int num_htree_groups, num_htree_groups_max, color_cache_bits;
+  VP8LBitReader* br;
   VP8LDecoder* dec = VP8LNew();
   if (dec == NULL) goto Error;
-  VP8LBitReader* const br = &dec->br_;
+  br = &dec->br_;
   VP8LInitBitReader(br, data, size);
 
-  const int color_cache_bits = VP8LReadBits(br, kColorCacheBitsBits);
+  color_cache_bits = VP8LReadBits(br, kColorCacheBitsBits);
   if (color_cache_bits < 1 || color_cache_bits > MAX_CACHE_BITS) goto Error;
 
-  const int num_htree_groups = VP8LReadBits(br, kNumHtreeGroupsBits);
+  num_htree_groups = VP8LReadBits(br, kNumHtreeGroupsBits);
   // 'num_htree_groups' cannot be 0 as it is built from a non-empty image.
-  if (num_htree_groups == 0) goto Error;
+  if (num_htree_groups == 0) return;
   // This variable is only useful when mapping is not NULL.
-  const int num_htree_groups_max = num_htree_groups;
+  num_htree_groups_max = num_htree_groups;
   (void)ReadHuffmanCodesHelper(color_cache_bits, num_htree_groups,
                                num_htree_groups_max, mapping, dec,
                                &huffman_tables, &htree_groups);
 
- Error:
+Error:
   WebPSafeFree(mapping);
   VP8LHtreeGroupsFree(htree_groups);
   VP8LHuffmanTablesDeallocate(&huffman_tables);
   VP8LDelete(dec);
-  return 0;
 }
+
+}  // namespace
+
+FUZZ_TEST(Huffman, HuffmanTest).WithDomains(fuzztest::String());
diff --git a/tests/fuzzer/makefile.unix b/tests/fuzzer/makefile.unix
deleted file mode 100644
index 3a3aff0a..00000000
--- a/tests/fuzzer/makefile.unix
+++ /dev/null
@@ -1,31 +0,0 @@
-# This Makefile will compile all fuzzing targets. It doesn't check tool
-# requirements and paths may need to be updated depending on your environment.
-# Note a clang 6+ toolchain is assumed for use of -fsanitize=fuzzer.
-
-CC = clang
-CXX = clang++
-CFLAGS = -fsanitize=fuzzer -I../../src -I../.. -Wall -Wextra
-CXXFLAGS = $(CFLAGS)
-LDFLAGS = -fsanitize=fuzzer
-LDLIBS = ../../src/mux/libwebpmux.a ../../src/demux/libwebpdemux.a
-LDLIBS += ../../src/libwebp.a ../../imageio/libimageio_util.a
-LDLIBS += ../../sharpyuv/libsharpyuv.a
-
-FUZZERS = advanced_api_fuzzer animation_api_fuzzer animdecoder_fuzzer
-FUZZERS += animencoder_fuzzer enc_dec_fuzzer huffman_fuzzer
-FUZZERS += mux_demux_api_fuzzer simple_api_fuzzer
-
-%.o: fuzz_utils.h img_alpha.h img_grid.h img_peak.h
-all: $(FUZZERS)
-
-define FUZZER_template
-$(1): $$(addsuffix .o, $(1)) $(LDLIBS)
-OBJS += $$(addsuffix .o, $(1))
-endef
-
-$(foreach fuzzer, $(FUZZERS), $(eval $(call FUZZER_template, $(fuzzer))))
-
-clean:
-	$(RM) $(FUZZERS) $(OBJS)
-
-.PHONY: all clean
diff --git a/tests/fuzzer/mux_demux_api_fuzzer.c b/tests/fuzzer/mux_demux_api_fuzzer.cc
similarity index 79%
rename from tests/fuzzer/mux_demux_api_fuzzer.c
rename to tests/fuzzer/mux_demux_api_fuzzer.cc
index f5983e8d..4d853518 100644
--- a/tests/fuzzer/mux_demux_api_fuzzer.c
+++ b/tests/fuzzer/mux_demux_api_fuzzer.cc
@@ -14,23 +14,30 @@
 //
 ////////////////////////////////////////////////////////////////////////////////
 
+#include <cstddef>
+#include <cstdint>
+#include <string_view>
+
 #include "./fuzz_utils.h"
 #include "src/webp/demux.h"
 #include "src/webp/mux.h"
 
-int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
+namespace {
+
+void MuxDemuxApiTest(std::string_view data_in, bool mux) {
+  const size_t size = data_in.size();
   WebPData webp_data;
   WebPDataInit(&webp_data);
   webp_data.size = size;
-  webp_data.bytes = data;
+  webp_data.bytes = reinterpret_cast<const uint8_t*>(data_in.data());
 
   // Extracted chunks and frames are not processed or decoded,
   // which is already covered extensively by the other fuzz targets.
 
-  if (size & 1) {
+  if (mux) {
     // Mux API
     WebPMux* mux = WebPMuxCreate(&webp_data, size & 2);
-    if (!mux) return 0;
+    if (!mux) return;
 
     WebPData chunk;
     (void)WebPMuxGetChunk(mux, "EXIF", &chunk);
@@ -45,7 +52,7 @@ int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
 
     WebPMuxError status;
     WebPMuxFrameInfo info;
-    for (int i = 0; i < kFuzzFrameLimit; i++) {
+    for (int i = 0; i < fuzz_utils::kFuzzFrameLimit; i++) {
       status = WebPMuxGetFrame(mux, i + 1, &info);
       if (status == WEBP_MUX_NOT_FOUND) {
         break;
@@ -63,11 +70,11 @@ int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
       demux = WebPDemuxPartial(&webp_data, &state);
       if (state < WEBP_DEMUX_PARSED_HEADER) {
         WebPDemuxDelete(demux);
-        return 0;
+        return;
       }
     } else {
       demux = WebPDemux(&webp_data);
-      if (!demux) return 0;
+      if (!demux) return;
     }
 
     WebPChunkIterator chunk_iter;
@@ -83,7 +90,7 @@ int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
 
     WebPIterator iter;
     if (WebPDemuxGetFrame(demux, 1, &iter)) {
-      for (int i = 1; i < kFuzzFrameLimit; i++) {
+      for (int i = 1; i < fuzz_utils::kFuzzFrameLimit; i++) {
         if (!WebPDemuxNextFrame(&iter)) break;
       }
     }
@@ -91,6 +98,12 @@ int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
     WebPDemuxReleaseIterator(&iter);
     WebPDemuxDelete(demux);
   }
-
-  return 0;
 }
+
+}  // namespace
+
+FUZZ_TEST(MuxDemuxApi, MuxDemuxApiTest)
+    .WithDomains(
+        fuzztest::String()
+            .WithMaxSize(fuzz_utils::kMaxWebPFileSize + 1),
+        /*mux=*/fuzztest::Arbitrary<bool>());
diff --git a/tests/fuzzer/oss-fuzz/build.sh b/tests/fuzzer/oss-fuzz/build.sh
index f2931e8b..e8c34eca 100644
--- a/tests/fuzzer/oss-fuzz/build.sh
+++ b/tests/fuzzer/oss-fuzz/build.sh
@@ -15,61 +15,69 @@
 #
 ################################################################################
 
+# This script is meant to be run by the oss-fuzz infrastructure from the script
+# https://github.com/google/oss-fuzz/blob/master/projects/libwebp/build.sh
+# It builds the different fuzz targets.
+
+# To test changes to this file:
+# - make changes and commit to your REPO
+# - run:
+#     git clone --depth=1 git@github.com:google/oss-fuzz.git
+#     cd oss-fuzz
+# - modify projects/libwebp/Dockerfile to point to your REPO
+# - run:
+#     python3 infra/helper.py build_image libwebp
+#     # enter 'y' and wait for everything to be downloaded
+# - run:
+#     python3 infra/helper.py build_fuzzers --sanitizer address libwebp
+#     # wait for the tests to be built
+# And then run the fuzzer locally, for example:
+#     python3 infra/helper.py run_fuzzer libwebp \
+#     --sanitizer address \
+#     animencoder_fuzzer__AnimEncoder.AnimEncoderTest
+
 set -eu
 
 # limit allocation size to reduce spurious OOMs
 WEBP_CFLAGS="$CFLAGS -DWEBP_MAX_IMAGE_SIZE=838860800" # 800MiB
 
-./autogen.sh
-CFLAGS="$WEBP_CFLAGS" ./configure \
-  --enable-asserts \
-  --enable-libwebpdemux \
-  --enable-libwebpmux \
-  --disable-shared \
-  --disable-jpeg \
-  --disable-tiff \
-  --disable-gif \
-  --disable-wic
-make clean
-make -j$(nproc)
+export CFLAGS="$WEBP_CFLAGS"
+cmake -S . -B build -DWEBP_BUILD_FUZZTEST=ON
+cd build && make -j$(nproc) && cd ..
 
 find $SRC/libwebp-test-data -type f -size -32k -iname "*.webp" \
   -exec zip -qju fuzz_seed_corpus.zip "{}" \;
 
-webp_libs=(
-  src/demux/.libs/libwebpdemux.a
-  src/mux/.libs/libwebpmux.a
-  src/.libs/libwebp.a
-  imageio/.libs/libimageio_util.a
-  sharpyuv/.libs/libsharpyuv.a
-)
-webp_c_fuzzers=(
-  advanced_api_fuzzer
-  animation_api_fuzzer
-  huffman_fuzzer
-  mux_demux_api_fuzzer
-  simple_api_fuzzer
-)
-webp_cxx_fuzzers=(
-  animdecoder_fuzzer
-  animencoder_fuzzer
-  enc_dec_fuzzer
-)
-
-for fuzzer in "${webp_c_fuzzers[@]}"; do
-  $CC $CFLAGS -Isrc -I. tests/fuzzer/${fuzzer}.c -c -o tests/fuzzer/${fuzzer}.o
-  $CXX $CXXFLAGS $LIB_FUZZING_ENGINE \
-    tests/fuzzer/${fuzzer}.o -o $OUT/${fuzzer} \
-    "${webp_libs[@]}"
-done
-
-for fuzzer in "${webp_cxx_fuzzers[@]}"; do
-  $CXX $CXXFLAGS -Isrc -I. $LIB_FUZZING_ENGINE \
-    tests/fuzzer/${fuzzer}.cc -o $OUT/${fuzzer} \
-    "${webp_libs[@]}"
-done
-
-for fuzzer in "${webp_c_fuzzers[@]}" "${webp_cxx_fuzzers[@]}"; do
-  cp fuzz_seed_corpus.zip $OUT/${fuzzer}_seed_corpus.zip
-  cp tests/fuzzer/fuzz.dict $OUT/${fuzzer}.dict
-done
+# Restrict fuzztest tests to the only compatible fuzz engine: libfuzzer.
+if [[ "$FUZZING_ENGINE" == "libfuzzer" ]]; then
+  # build fuzztests
+  # The following is taken from https://github.com/google/oss-fuzz/blob/31ac7244748ea7390015455fb034b1f4eda039d9/infra/base-images/base-builder/compile_fuzztests.sh#L59
+  # Iterate the fuzz binaries and list each fuzz entrypoint in the binary. For
+  # each entrypoint create a wrapper script that calls into the binaries the
+  # given entrypoint as argument.
+  # The scripts will be named:
+  # {binary_name}@{fuzztest_entrypoint}
+  FUZZ_TEST_BINARIES_OUT_PATHS=$(find ./build/tests/fuzzer/ -executable -type f)
+  echo "Fuzz binaries: $FUZZ_TEST_BINARIES_OUT_PATHS"
+  for fuzz_main_file in $FUZZ_TEST_BINARIES_OUT_PATHS; do
+    FUZZ_TESTS=$($fuzz_main_file --list_fuzz_tests | cut -d ' ' -f 4)
+    cp -f ${fuzz_main_file} $OUT/
+    fuzz_basename=$(basename $fuzz_main_file)
+    chmod -x $OUT/$fuzz_basename
+    for fuzz_entrypoint in $FUZZ_TESTS; do
+      TARGET_FUZZER="${fuzz_basename}@$fuzz_entrypoint"
+      # Write executer script
+      echo "#!/bin/sh
+# LLVMFuzzerTestOneInput for fuzzer detection.
+this_dir=\$(dirname \"\$0\")
+export TEST_DATA_DIRS=\$this_dir/corpus
+chmod +x \$this_dir/$fuzz_basename
+\$this_dir/$fuzz_basename --fuzz=$fuzz_entrypoint -- \$@
+chmod -x \$this_dir/$fuzz_basename" > $OUT/$TARGET_FUZZER
+      chmod +x $OUT/$TARGET_FUZZER
+    done
+  # Copy data.
+  cp fuzz_seed_corpus.zip $OUT/${fuzz_basename}_seed_corpus.zip
+  cp tests/fuzzer/fuzz.dict $OUT/${fuzz_basename}.dict
+  done
+fi
diff --git a/tests/fuzzer/patch.sh b/tests/fuzzer/patch.sh
new file mode 100755
index 00000000..7034d10f
--- /dev/null
+++ b/tests/fuzzer/patch.sh
@@ -0,0 +1,10 @@
+#!/bin/sh
+# Fixes for https://github.com/google/fuzztest/issues/1124
+sed -i -e "s/-fsanitize=address//g" -e "s/-DADDRESS_SANITIZER//g" \
+  ./cmake/FuzzTestFlagSetup.cmake
+# Fixes for https://github.com/google/fuzztest/issues/1125
+before="if (IsEnginePlaceholderInput(data)) return;"
+after="if (data.size() == 0) return;"
+sed -i "s/${before}/${after}/" ./fuzztest/internal/compatibility_mode.cc
+sed -i "s/set(GTEST_HAS_ABSL ON)/set(GTEST_HAS_ABSL OFF)/" \
+  ./cmake/BuildDependencies.cmake
diff --git a/tests/fuzzer/simple_api_fuzzer.c b/tests/fuzzer/simple_api_fuzzer.cc
similarity index 84%
rename from tests/fuzzer/simple_api_fuzzer.c
rename to tests/fuzzer/simple_api_fuzzer.cc
index 3a4288a4..3d1b5c3b 100644
--- a/tests/fuzzer/simple_api_fuzzer.c
+++ b/tests/fuzzer/simple_api_fuzzer.cc
@@ -14,15 +14,23 @@
 //
 ////////////////////////////////////////////////////////////////////////////////
 
+#include <cstddef>
+#include <cstdint>
+#include <string_view>
+
 #include "./fuzz_utils.h"
 #include "src/webp/decode.h"
 
-int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
-  int w, h;
-  if (!WebPGetInfo(data, size, &w, &h)) return 0;
-  if ((size_t)w * h > kFuzzPxLimit) return 0;
+namespace {
 
-  const uint8_t value = FuzzHash(data, size);
+void SimpleApiTest(std::string_view data_in) {
+  const uint8_t* const data = reinterpret_cast<const uint8_t*>(data_in.data());
+  const size_t size = data_in.size();
+  int w, h;
+  if (!WebPGetInfo(data, size, &w, &h)) return;
+  if ((size_t)w * h > fuzz_utils::kFuzzPxLimit) return;
+
+  const uint8_t value = fuzz_utils::FuzzHash(data, size);
   uint8_t* buf = NULL;
 
   // For *Into functions, which decode into an external buffer, an
@@ -84,6 +92,11 @@ int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
   }
 
   if (buf) WebPFree(buf);
-
-  return 0;
 }
+
+}  // namespace
+
+FUZZ_TEST(SimpleApi, SimpleApiTest)
+    .WithDomains(
+        fuzztest::String()
+            .WithMaxSize(fuzz_utils::kMaxWebPFileSize + 1));