diff --git a/.github/workflows/Web.yml b/.github/workflows/Web.yml
index ed02e981..fa2b34dc 100644
--- a/.github/workflows/Web.yml
+++ b/.github/workflows/Web.yml
@@ -11,7 +11,7 @@ jobs:
       - name: Setup emsdk                 
         uses: mymindstorm/setup-emsdk@v10
         with:
-          version: 2.0.21
+          version: 3.1.51
           actions-cache-folder: 'emsdk-cache'
       - name: Build
         run: |
diff --git a/CMakeLists.txt b/CMakeLists.txt
index d3b563e4..6f215f5a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -19,7 +19,7 @@ set(BUILD_STATIC_LIBS ON)
 set(DPP_BUILD_TEST OFF)
 
 if (WIN32)
-    set(HYDRA_DEFINITIONS ${HYDRA_DEFINITIONS} HYDRA_WINDOWS WIN32_LEAN_AND_MEAN)
+    set(HYDRA_DEFINITIONS ${HYDRA_DEFINITIONS} HYDRA_WINDOWS WIN32_LEAN_AND_MEAN NOMINMAX)
     set(HYDRA_WINDOWS 1)
 elseif(APPLE)
     set(HYDRA_DEFINITIONS ${HYDRA_DEFINITIONS} HYDRA_MACOS)
@@ -80,9 +80,7 @@ elseif(HYDRA_IOS)
 elseif(HYDRA_WEB)
     set(LONG_INT 8) # for openssl
     set(CMAKE_EXECUTABLE_SUFFIX ".html")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -sEXPORTED_RUNTIME_METHODS=ccall")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -sEXPORTED_RUNTIME_METHODS=ccall")
-    set_target_properties(hydra PROPERTIES LINK_FLAGS "-sALLOW_MEMORY_GROWTH -s TOTAL_MEMORY=192MB -lidbfs.js -s ELIMINATE\_DUPLICATE\_FUNCTIONS=1 -flto -s USE_CLOSURE_COMPILER=0 --closure 0")
+    set_target_properties(hydra PROPERTIES LINK_FLAGS "-sEXPORTED_FUNCTIONS=[_main_impl,_main] -sEXPORTED_RUNTIME_METHODS=ccall -sNO_DISABLE_EXCEPTION_CATCHING -sASSERTIONS -sALLOW_MEMORY_GROWTH -s TOTAL_MEMORY=192MB -lidbfs.js -s ELIMINATE\_DUPLICATE\_FUNCTIONS=1 -flto -s USE_CLOSURE_COMPILER=0 --closure 0")
 else()
     message(FATAL_ERROR "Unsupported platform")
 endif()
@@ -91,12 +89,9 @@ endif()
 if (MSVC)
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /MT /Ox /Ob2 /Oi /Ot /GT /GF /GS- /fp:fast /fp:except- /MP /sdl- /EHsc /D_SECURE_SCL=0 /D_SCL_SECURE_NO_WARNINGS /D_ITERATOR_DEBUG_LEVEL=0 /D_HAS_ITERATOR_DEBUGGING=0")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /MT /Ox /Ob2 /Oi /Ot /GT /GF /GS- /fp:fast /fp:except- /MP /sdl- /EHsc /D_SECURE_SCL=0 /D_SCL_SECURE_NO_WARNINGS /D_ITERATOR_DEBUG_LEVEL=0 /D_HAS_ITERATOR_DEBUGGING=0")
-elseif(NOT HYDRA_WEB)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -O3")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g -O3")
 else()
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3 -DNDEBUG") # it's best to strip out debug symbols for web builds
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O3 -DNDEBUG")     # to reduce the binary size
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -O3") # TODO: it's best to strip out debug symbols for web builds
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g -O3")     # to reduce the binary size
 endif()
 
 option(BUILD_QT "Build the Qt frontend" OFF)
diff --git a/include/compatibility.hxx b/include/compatibility.hxx
index 323ed78a..b59edb7d 100644
--- a/include/compatibility.hxx
+++ b/include/compatibility.hxx
@@ -1,10 +1,30 @@
 #pragma once
 
 #include <cstdint>
+#include <filesystem>
+#include <log.hxx>
+#include <span>
 #include <sstream>
 #include <string>
 #include <vector>
 
+#ifdef HYDRA_WEB
+#include <emscripten.h>
+#endif
+
+static void sync_fs()
+{
+#ifdef HYDRA_WEB
+    EM_ASM(
+        FS.syncfs(false, function (err) {
+            if (err) {
+                console.log("Failed to sync FS: " + err);
+            }
+        });
+    );
+#endif
+}
+
 namespace hydra
 {
     inline std::vector<std::string> split(const std::string& s, char delimiter)
@@ -44,4 +64,42 @@ namespace hydra
         return hash;
     }
 
+    inline std::string fread(const std::filesystem::path& path)
+    {
+        FILE* file = std::fopen(path.string().c_str(), "rb");
+        if (!file)
+        {
+            file = std::fopen(path.string().c_str(), "wb");
+            if (!file)
+            {
+                hydra::log("Failed to open file: %s\n", path.string().c_str());
+                return "";
+            }
+            std::fclose(file);
+            sync_fs();
+            return "";
+        }
+
+        std::string contents;
+        std::fseek(file, 0, SEEK_END);
+        contents.resize(std::ftell(file));
+        std::rewind(file);
+        std::fread(&contents[0], 1, contents.size(), file);
+        std::fclose(file);
+        return contents;
+    }
+
+    inline void fwrite(const std::filesystem::path& path, std::span<const uint8_t> contents)
+    {
+        FILE* file = std::fopen(path.string().c_str(), "wb");
+        if (!file)
+        {
+            hydra::log("Failed to open file: %s\n", path.string().c_str());
+            return;
+        }
+        std::fwrite(contents.data(), 1, contents.size(), file);
+        std::fclose(file);
+        sync_fs();
+    }
+
 } // namespace hydra
diff --git a/include/settings.hxx b/include/settings.hxx
index 01653110..5cc749cb 100644
--- a/include/settings.hxx
+++ b/include/settings.hxx
@@ -44,17 +44,22 @@ public:
     {
         map().clear();
         save_path() = path;
-        std::ifstream ifs(save_path());
-        if (ifs.good())
+        std::string data = hydra::fread(path);
+        if (data.empty())
         {
-            json j_map;
-            ifs >> j_map;
-            map() = j_map.get<std::map<std::string, std::string>>();
+            return;
         }
-        else
+
+        json j_map;
+        try
         {
-            throw std::runtime_error("Failed to open settings");
+            j_map = json::parse(data);
+        } catch (std::exception& e)
+        {
+            hydra::log("Failed to parse settings file: {}", e.what());
+            return;
         }
+        map() = j_map.get<std::map<std::string, std::string>>();
     }
 
     static std::string Get(const std::string& key)
@@ -71,9 +76,9 @@ public:
     static void Set(const std::string& key, const std::string& value)
     {
         map()[key] = value;
-        std::ofstream ofs(save_path(), std::ios::trunc);
         json j_map(map());
-        ofs << j_map << std::endl;
+        std::string data = j_map.dump(4);
+        hydra::fwrite(save_path(), std::span<const uint8_t>((uint8_t*)data.data(), data.size()));
     }
 
     static bool IsEmpty()
@@ -98,6 +103,8 @@ public:
             std::string applicationName;
             std::getline(cmdline, applicationName, '\0');
             dir = std::filesystem::path("/data") / "data" / applicationName / "files";
+#elif defined(HYDRA_WEB)
+            dir = std::filesystem::path("/hydra");
 #endif
             if (dir.empty())
             {
@@ -161,7 +168,7 @@ public:
 
         if (!std::filesystem::exists(Settings::Get("core_path")))
         {
-            printf("Failed to find initialize core info\n");
+            printf("Failed to find core info: %s\n", Settings::Get("core_path").c_str());
             return;
         }
 
diff --git a/src/main.cxx b/src/main.cxx
index 9469d46c..9c8221b9 100644
--- a/src/main.cxx
+++ b/src/main.cxx
@@ -9,6 +9,10 @@
 #endif
 #include <settings.hxx>
 
+#ifdef HYDRA_WEB
+#include <emscripten.h>
+#endif
+
 // clang-format off
 
 const char* options =
@@ -110,12 +114,34 @@ int bot_main_cb(struct argparse*, const struct argparse_option*)
 #endif
 }
 
-int main(int argc, char* argv[])
+#if defined(HYDRA_WEB)
+// Setup the offline file system
+EM_JS(void, em_init_fs, (),{
+        FS.mkdir('/hydra');
+        // Then mount with IDBFS type
+        FS.mount(IDBFS, {}, '/hydra');
+        FS.mkdir('/hydra/cores');
+        FS.mount(IDBFS, {}, '/hydra/cores');
+        FS.mkdir('/hydra/cache');
+        FS.mount(IDBFS, {}, '/hydra/cache');
+        // Then sync
+        FS.syncfs(true, function (err) {
+            Module.ccall('main_impl');
+        });
+  });
+#endif
+
+extern "C" int main_impl(int argc, char* argv[])
 {
+    printf("hydra version %s\n", HYDRA_VERSION);
     auto settings_path = Settings::GetSavePath() / "settings.json";
     Settings::Open(settings_path);
     Settings::InitCoreInfo();
 
+#ifdef HYDRA_WEB
+    return imgui_main(argc, argv);
+#endif
+
     if (argc == 1)
     {
         return imgui_main(argc, argv);
@@ -144,3 +170,12 @@ int main(int argc, char* argv[])
     argparse_parse(&argparse, argc, const_cast<const char**>(argv));
     return 0;
 }
+
+int main(int argc, char* argv[])
+{
+#ifdef HYDRA_WEB
+    em_init_fs();
+#else
+    return main_impl(argc, argv);
+#endif
+}