diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1243b4d9..8cdc2e47 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,7 +8,9 @@ execute_process(COMMAND git rev-parse --short HEAD
     OUTPUT_STRIP_TRAILING_WHITESPACE
 )
 
-find_package(GLEW REQUIRED)
+if (NOT EMSCRIPTEN)
+    find_package(GLEW REQUIRED)
+endif()
 find_package(fmt REQUIRED)
 
 include(cmake/utils.cmake)
@@ -21,6 +23,9 @@ option(ESSAGUI_EXAMPLES "Compile examples" ON)
 option(ESSAGUI_UTIL_ONLY "Compile only EssaUtil (no GUI or Engine)" OFF)
 
 include_directories(${Essa_SOURCE_DIR})
+if (EMSCRIPTEN)
+    include_directories(${fmt_DIR}/../../../include)
+endif()
 
 add_subdirectory(EssaUtil)
 
diff --git a/Essa/GUI/CMakeLists.txt b/Essa/GUI/CMakeLists.txt
index e78fbf2f..145de547 100644
--- a/Essa/GUI/CMakeLists.txt
+++ b/Essa/GUI/CMakeLists.txt
@@ -85,8 +85,3 @@ set_target_properties(GUI PROPERTIES OUTPUT_NAME "essa-gui")
 set_target_properties(GUI PROPERTIES SOVERSION ${ESSA_GIT_REVISION})
 essautil_setup_target(GUI)
 target_link_libraries(GUI PUBLIC Util LLGL-OpenGL LLGL-Window LLGL-Resources)
-
-# FIXME: This breaks build of eml/AST.cpp somewhere in Value::string()
-target_compile_options(GUI PRIVATE -Wno-restrict)
-# FIXME: This breaks build of RadioGroup::add_widget().
-target_compile_options(GUI PUBLIC -Wno-address)
diff --git a/Essa/GUI/Debug.hpp b/Essa/GUI/Debug.hpp
index 28730e9a..4407ffcb 100644
--- a/Essa/GUI/Debug.hpp
+++ b/Essa/GUI/Debug.hpp
@@ -33,9 +33,11 @@ class DebugSwitch {
     /*global*/ ::GUI::DebugSwitch __debug_##name { \
 #        name                                      \
     }
-#define DBG_PRINTLN(name, fmtstr, ...)                                    \
-    {                                                                     \
-        if (DBG_ENABLED(name)) {                                          \
-            fmt::vprint(fmtstr "\n", fmt::make_format_args(__VA_ARGS__)); \
-        }                                                                 \
-    }
+
+#define DBG_PRINTLN(name, fmtstr, ...)                              \
+    do {                                                            \
+        if (DBG_ENABLED(name)) {                                    \
+            const auto& vargs = fmt::make_format_args(__VA_ARGS__); \
+            fmt::vprint(fmtstr "\n", vargs);                        \
+        }                                                           \
+    } while (false)
diff --git a/Essa/GUI/EML/AST.cpp b/Essa/GUI/EML/AST.cpp
index 26f54779..8cca8390 100644
--- a/Essa/GUI/EML/AST.cpp
+++ b/Essa/GUI/EML/AST.cpp
@@ -58,7 +58,7 @@ template<class... Ts> struct overloaded : Ts... {
 
 std::string Value::string() const {
     return std::visit(
-        overloaded {
+        Util::Overloaded {
             [](double d) -> std::string { return fmt::format("{}", d); },
             [](bool b) -> std::string { return b ? "true" : "false"; },
             [](Util::UString const& str) -> std::string { return "\"" + str.encode() + "\""; },
diff --git a/Essa/GUI/EventLoop.cpp b/Essa/GUI/EventLoop.cpp
index b7c51397..86b2fbc9 100644
--- a/Essa/GUI/EventLoop.cpp
+++ b/Essa/GUI/EventLoop.cpp
@@ -11,6 +11,8 @@
 
 #ifdef __linux__
 #    include <sys/prctl.h>
+#elif defined(__EMSCRIPTEN__)
+#    include <emscripten.h>
 #endif
 
 using namespace std::chrono_literals;
@@ -39,8 +41,24 @@ void increase_system_timer_resolution() {
 void EventLoop::run() {
     auto old_event_loop = s_current_event_loop;
     s_current_event_loop = this;
-    Util::ScopeGuard guard = [&]() { s_current_event_loop = old_event_loop; };
+#ifdef __EMSCRIPTEN__
+    if (!old_event_loop) {
+        emscripten_set_main_loop(
+            []() {
+                s_current_event_loop->tick();
+                if (!s_current_event_loop->m_running) {
+                    // FIXME: Make this work properly with dialogs. It may require
+                    //        refactoring them to be asynchronous ?
+                    emscripten_cancel_main_loop();
+                }
+            },
+            0, true
+        );
+        return;
+    }
+#else
 
+    Util::ScopeGuard guard = [&]() { s_current_event_loop = old_event_loop; };
     Util::Clock clock;
 
     increase_system_timer_resolution();
@@ -73,6 +91,7 @@ void EventLoop::run() {
             }
         }
     }
+#endif
 }
 
 EventLoop::TimerHandle EventLoop::set_timeout(Timer::Clock::duration const& timeout, Timer::Callback&& callback) {
diff --git a/Essa/GUI/Graphics/DefaultGUIShader.cpp b/Essa/GUI/Graphics/DefaultGUIShader.cpp
index fd85021f..799fe48e 100644
--- a/Essa/GUI/Graphics/DefaultGUIShader.cpp
+++ b/Essa/GUI/Graphics/DefaultGUIShader.cpp
@@ -6,6 +6,45 @@
 
 namespace Gfx {
 
+#ifdef __EMSCRIPTEN__
+static std::string_view VertexShader = R"~~~(// Default GUI VS
+precision highp float;
+precision highp int;
+
+attribute vec2 position;
+attribute vec4 color;
+attribute vec2 texCoords;
+
+uniform mat4 projectionMatrix;
+uniform mat4 viewMatrix;
+uniform mat4 modelMatrix;
+uniform mat4 submodelMatrix;
+
+varying vec4 fColor;
+varying vec2 fTexCoords;
+
+void main() {
+    fColor = color;
+    fTexCoords = texCoords;
+    gl_Position = projectionMatrix * (viewMatrix * (modelMatrix * (submodelMatrix * vec4(position, 0, 1))));
+}
+)~~~";
+
+static std::string_view FragmentShader = R"~~~(// Default GUI FS
+precision highp float;
+precision highp int;
+
+varying vec4 fColor;
+varying vec2 fTexCoords;
+
+uniform sampler2D texture;
+uniform bool textureSet;
+
+void main() {
+    gl_FragColor = textureSet ? fColor * texture2D(texture, fTexCoords.xy) : fColor;
+}
+)~~~";
+#else
 static std::string_view VertexShader = R"~~~(// Default GUI VS
 #version 330 core
 
@@ -41,6 +80,7 @@ void main() {
     gl_FragColor = textureSet ? fColor * texture2D(texture, fTexCoords.xy) : fColor;
 }
 )~~~";
+#endif
 
 std::string_view DefaultGUIShader::source(llgl::ShaderType type) const {
     switch (type) {
diff --git a/Essa/GUI/Graphics/Drawing/Shape.hpp b/Essa/GUI/Graphics/Drawing/Shape.hpp
index 9c71d2a5..f28c025e 100644
--- a/Essa/GUI/Graphics/Drawing/Shape.hpp
+++ b/Essa/GUI/Graphics/Drawing/Shape.hpp
@@ -80,7 +80,6 @@ class Shape {
 
     private:
         Shape const& m_shape;
-        size_t m_index = 0;
     };
 
     Points points() const { return Points { *this }; }
diff --git a/Essa/GUI/Graphics/GUIBuilder.hpp b/Essa/GUI/Graphics/GUIBuilder.hpp
index a9176f6b..0f6f7c92 100644
--- a/Essa/GUI/Graphics/GUIBuilder.hpp
+++ b/Essa/GUI/Graphics/GUIBuilder.hpp
@@ -54,6 +54,7 @@ class GUIBuilder : public llgl::Builder<Vertex, GUIBuilderRenderRange> {
 
     virtual void
     render_range(llgl::Renderer& renderer, llgl::VertexArray<Vertex> const& vao, GUIBuilderRenderRange const& range) const override {
+        static Gfx::DefaultGUIShader m_shader;
         Gfx::DefaultGUIShader::Uniforms uniforms;
         uniforms.set_transform(range.model.matrix(), range.view.matrix(), range.projection.matrix());
         uniforms.set_texture(range.texture);
@@ -62,7 +63,6 @@ class GUIBuilder : public llgl::Builder<Vertex, GUIBuilderRenderRange> {
         renderer.draw_vertices(vao, llgl::DrawState { m_shader, uniforms, range.type }, range.first, range.size);
     }
 
-    mutable Gfx::DefaultGUIShader m_shader;
     llgl::Projection m_projection;
     llgl::Transform m_view;
     llgl::Transform m_model;
diff --git a/Essa/GUI/Graphics/ResourceManager.cpp b/Essa/GUI/Graphics/ResourceManager.cpp
index 33cec7c7..9b087da7 100644
--- a/Essa/GUI/Graphics/ResourceManager.cpp
+++ b/Essa/GUI/Graphics/ResourceManager.cpp
@@ -77,6 +77,8 @@ llgl::TTFFont& ResourceManager::fixed_width_font() const {
 static std::filesystem::path exec_path() {
 #ifdef __linux__
     return std::filesystem::read_symlink("/proc/" + std::to_string(getpid()) + "/exe").parent_path();
+#elif __EMSCRIPTEN__
+    return "/";
 #else
 #    error OS not supported (install linux)
 #endif
diff --git a/Essa/GUI/Overlays/FileExplorer.cpp b/Essa/GUI/Overlays/FileExplorer.cpp
index 3ef9fbd0..2c3c358e 100644
--- a/Essa/GUI/Overlays/FileExplorer.cpp
+++ b/Essa/GUI/Overlays/FileExplorer.cpp
@@ -15,7 +15,9 @@
 #include <EssaUtil/Config.hpp>
 #include <EssaUtil/UnitDisplay.hpp>
 #include <EssaUtil/Units.hpp>
+#include <chrono>
 #include <filesystem>
+#include <fmt/chrono.h>
 #include <fstream>
 #include <functional>
 #include <iostream>
@@ -63,12 +65,13 @@ Variant FileModel::data(Node row, size_t column) const {
     case 4: {
         return Util::UString { file_type(file) };
     }
-    case 3:
-        std::time_t cftime
-            = std::chrono::system_clock::to_time_t(std::chrono::file_clock::to_sys(std::filesystem::last_write_time(file.path)));
-        std::string string = std::asctime(std::localtime(&cftime));
-        string.pop_back(); // trailing \n
-        return Util::UString { string };
+    case 3: {
+        using namespace std::chrono_literals;
+        namespace ch = std::chrono;
+        // FIXME: Use clock cast when clang supports this.
+        auto time = ch::file_clock::to_sys(ch::time_point_cast<ch::sys_seconds::duration>(std::filesystem::last_write_time(file.path)));
+        return Util::UString { fmt::format("{:%x %X}", time) };
+    }
     }
     return "";
 }
diff --git a/Essa/GUI/Widgets/Container.cpp b/Essa/GUI/Widgets/Container.cpp
index 72f15663..fe654503 100644
--- a/Essa/GUI/Widgets/Container.cpp
+++ b/Essa/GUI/Widgets/Container.cpp
@@ -398,7 +398,9 @@ void Container::dump(unsigned depth) {
     for (unsigned i = 0; i < depth; i++)
         std::cout << "-   ";
     if (m_layout) {
-        std::cout << "layout: " << typeid(*m_layout).name() << std::endl;
+        // Note: Temporary variable is a workaround for -Wpotentially-evaluated-expression on Clang
+        auto& layout = *m_layout;
+        std::cout << "layout: " << typeid(layout).name() << std::endl;
     }
     else {
         std::cout << "layout: NONE!" << std::endl;
diff --git a/Essa/GUI/Widgets/ListView.cpp b/Essa/GUI/Widgets/ListView.cpp
index d52bce6b..0f70eae1 100644
--- a/Essa/GUI/Widgets/ListView.cpp
+++ b/Essa/GUI/Widgets/ListView.cpp
@@ -93,34 +93,34 @@ void ListView::draw(Gfx::Painter& wnd) const {
                 // configurable
 
                 std::visit(
-                    overloaded { [&](Util::UString const& data) {
-                                    Gfx::Text text { data, Application::the().bold_font() };
-                                    text.set_font_size(theme().label_font_size);
-                                    text.set_fill_color(c % 2 == 0 ? list_even.text : list_odd.text);
-                                    text.align(
-                                        Align::CenterLeft, { (cell_position + Util::Vector2i(5, 0)).cast<float>(), cell_size.cast<float>() }
-                                    );
-                                    text.draw(wnd);
-                                },
-                                 [&](Gfx::RichText const& data) {
-                                     Gfx::RichTextDrawable drawable { data,
-                                                                      {
-                                                                          .default_font = Application::the().font(),
-                                                                          .font_size = static_cast<int>(theme().label_font_size),
-                                                                          .text_alignment = GUI::Align::CenterLeft,
-                                                                      } };
-                                     drawable.set_rect({ (cell_position + Util::Vector2i(5, 0)).cast<float>(), cell_size.cast<float>() });
-                                     drawable.draw(wnd);
-                                 },
-                                 [&](llgl::Texture const* data) {
-                                     Gfx::RectangleDrawOptions rect;
-                                     rect.texture = data;
-                                     wnd.deprecated_draw_rectangle(
-                                         { { cell_position.x() + cell_size.x() / 2 - 8, cell_position.y() + cell_size.y() / 2 - 8 },
-                                           { 16, 16 } },
-                                         rect
-                                     );
-                                 } },
+                    Util::Overloaded {
+                        [&](Util::UString const& data) {
+                            Gfx::Text text { data, Application::the().bold_font() };
+                            text.set_font_size(theme().label_font_size);
+                            text.set_fill_color(c % 2 == 0 ? list_even.text : list_odd.text);
+                            text.align(
+                                Align::CenterLeft, { (cell_position + Util::Vector2i(5, 0)).cast<float>(), cell_size.cast<float>() }
+                            );
+                            text.draw(wnd);
+                        },
+                        [&](Gfx::RichText const& data) {
+                            Gfx::RichTextDrawable drawable { data,
+                                                             {
+                                                                 .default_font = Application::the().font(),
+                                                                 .font_size = static_cast<int>(theme().label_font_size),
+                                                                 .text_alignment = GUI::Align::CenterLeft,
+                                                             } };
+                            drawable.set_rect({ (cell_position + Util::Vector2i(5, 0)).cast<float>(), cell_size.cast<float>() });
+                            drawable.draw(wnd);
+                        },
+                        [&](llgl::Texture const* data) {
+                            Gfx::RectangleDrawOptions rect;
+                            rect.texture = data;
+                            wnd.deprecated_draw_rectangle(
+                                { { cell_position.x() + cell_size.x() / 2 - 8, cell_position.y() + cell_size.y() / 2 - 8 }, { 16, 16 } },
+                                rect
+                            );
+                        } },
                     data
                 );
             }
diff --git a/Essa/LLGL/OpenGL/Error.cpp b/Essa/LLGL/OpenGL/Error.cpp
index 80d515f2..4238e9f5 100644
--- a/Essa/LLGL/OpenGL/Error.cpp
+++ b/Essa/LLGL/OpenGL/Error.cpp
@@ -4,23 +4,25 @@
 
 #include <GL/glew.h>
 
-#include <GL/glu.h>
-#include <iostream>
 #include <Essa/LLGL/Window/AbstractOpenGLHelper.hpp>
+#include <iostream>
 
 namespace llgl::opengl {
 
 void enable_debug_output() {
     ensure_glew();
+
+#ifndef __EMSCRIPTEN__
     OpenGL::Enable(GL_DEBUG_OUTPUT);
     glDebugMessageCallback(
         []([[maybe_unused]] GLenum source, GLenum type, [[maybe_unused]] GLuint id, [[maybe_unused]] GLenum severity,
-           [[maybe_unused]] GLsizei length, const GLchar* message, [[maybe_unused]] const void* user_param) {
+           [[maybe_unused]] GLsizei length, GLchar const* message, [[maybe_unused]] void const* user_param) {
             if (type == GL_DEBUG_TYPE_ERROR)
                 std::cout << "GL Error: " << message << std::endl;
         },
         0
     );
+#endif
 }
 
 void handle_error(std::source_location location) {
diff --git a/Essa/LLGL/OpenGL/FBO.cpp b/Essa/LLGL/OpenGL/FBO.cpp
index 97f92a75..37951ec9 100644
--- a/Essa/LLGL/OpenGL/FBO.cpp
+++ b/Essa/LLGL/OpenGL/FBO.cpp
@@ -1,18 +1,16 @@
 #include "FBO.hpp"
 
-#include <Essa/LLGL/Window/AbstractOpenGLHelper.hpp>
 #include <Essa/LLGL/OpenGL/Extensions.hpp>
+#include <Essa/LLGL/Window/AbstractOpenGLHelper.hpp>
 #include <iostream>
 
 namespace llgl::opengl {
 
 FBO::FBO(Util::Size2u size) {
-    opengl::ensure_glew();
     OpenGL::GenFramebuffers(1, &m_fbo);
+    FBOScope scope { *this };
 
     resize(size);
-    FBOScope scope { *this };
-    OpenGL::FramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, m_depth_renderbuffer);
 
     GLenum buffers[] = { GL_COLOR_ATTACHMENT0 };
     OpenGL::DrawBuffers(1, buffers);
@@ -41,25 +39,35 @@ void FBO::bind(Target target) const {
 }
 
 void FBO::resize(Util::Size2u size) {
-    FBOScope scope { *this };
     if (m_color_texture.size() == size)
         return;
+
+    FBOScope scope { *this };
+
+    // Color
     if (!m_color_texture.id())
         m_color_texture = Texture::create_empty(size, Texture::Format::RGBA);
     else
         m_color_texture.recreate(size, Texture::Format::RGBA);
-    OpenGL::FramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, m_color_texture.id(), 0);
+
+    OpenGL::FramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_color_texture.id(), 0);
+    
+    // Depth
     if (m_depth_renderbuffer)
         OpenGL::DeleteRenderbuffers(1, &m_depth_renderbuffer);
+    
     OpenGL::GenRenderbuffers(1, &m_depth_renderbuffer);
     OpenGL::BindRenderbuffer(GL_RENDERBUFFER, m_depth_renderbuffer);
     OpenGL::RenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, size.x(), size.y());
+    OpenGL::FramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, m_depth_renderbuffer);
 
     // std::cout << "FBO: recreated with size " << size.x << "," << size.y << std::endl;
 }
 
 void FBO::set_label(std::string const& str) {
+#ifndef __EMSCRIPTEN__
     OpenGL::ObjectLabel(GL_FRAMEBUFFER, m_fbo, str.size(), str.data());
+#endif
     m_color_texture.set_label("FBO Texture: " + str);
 }
 
diff --git a/Essa/LLGL/OpenGL/Texture.cpp b/Essa/LLGL/OpenGL/Texture.cpp
index 95dcea30..5f892cb4 100644
--- a/Essa/LLGL/OpenGL/Texture.cpp
+++ b/Essa/LLGL/OpenGL/Texture.cpp
@@ -73,7 +73,7 @@ void Texture::ensure_initialized(Format format) {
 
         TextureBinder binder(*this);
         // std::cout << "glTexImage2D(" << m_size << ")\n";
-        OpenGL::TexImage2D(GL_TEXTURE_2D, 0, gl_format(format), m_size.x(), m_size.y(), 0, gl_format(format), GL_FLOAT, nullptr);
+        OpenGL::TexImage2D(GL_TEXTURE_2D, 0, gl_format(format), m_size.x(), m_size.y(), 0, gl_format(format), GL_UNSIGNED_BYTE, nullptr);
     }
 }
 
@@ -83,7 +83,7 @@ void Texture::recreate(Util::Size2u size, Format format) {
     if (m_id) {
         TextureBinder binder(*this);
         // std::cout << "glTexImage2D(" << m_size << ")\n";
-        glTexImage2D(GL_TEXTURE_2D, 0, gl_format(format), m_size.x(), m_size.y(), 0, gl_format(format), GL_FLOAT, nullptr);
+        glTexImage2D(GL_TEXTURE_2D, 0, gl_format(format), m_size.x(), m_size.y(), 0, gl_format(format), GL_UNSIGNED_BYTE, nullptr);
     }
 
     ensure_initialized(format);
@@ -126,6 +126,10 @@ void Texture::set_filtering(Filtering filtering) {
 
 void Texture::bind(Texture const* texture) { OpenGL::BindTexture(GL_TEXTURE_2D, texture ? texture->id() : 0); }
 
-void Texture::set_label(std::string const& label) { OpenGL::ObjectLabel(GL_TEXTURE, m_id, label.size(), label.data()); }
+void Texture::set_label([[maybe_unused]] std::string const& label) {
+#ifndef __EMSCRIPTEN__
+    OpenGL::ObjectLabel(GL_TEXTURE, m_id, label.size(), label.data());
+#endif
+}
 
 }
diff --git a/Essa/LLGL/Resources/CMakeLists.txt b/Essa/LLGL/Resources/CMakeLists.txt
index f9f63e09..dd7a6df4 100644
--- a/Essa/LLGL/Resources/CMakeLists.txt
+++ b/Essa/LLGL/Resources/CMakeLists.txt
@@ -4,4 +4,9 @@ set(SOURCES
     TTFFont.cpp
 )
 add_llgl_library(Resources resources)
-target_link_libraries(LLGL-Resources LLGL-Core LLGL-OpenGL SDL2_image SDL2_ttf)
+target_link_libraries(LLGL-Resources LLGL-Core LLGL-OpenGL)
+if (EMSCRIPTEN)
+    target_link_options(LLGL-Resources PUBLIC "SHELL:-s USE_SDL_IMAGE=2 -s USE_SDL_TTF=2 -s SDL2_IMAGE_FORMATS=\'[\"png\",\"jpg\"]\'")
+else()
+    target_link_libraries(LLGL-Resources SDL2_image SDL2_ttf)
+endif()
diff --git a/Essa/LLGL/Resources/ImageLoader.cpp b/Essa/LLGL/Resources/ImageLoader.cpp
index 44968f25..7b87b719 100644
--- a/Essa/LLGL/Resources/ImageLoader.cpp
+++ b/Essa/LLGL/Resources/ImageLoader.cpp
@@ -33,9 +33,11 @@ static Uint32 get_pixel(SDL_Surface& surface, Util::Point2u position) {
 }
 
 std::optional<Image> ImageLoader::load_from_file(std::string const& path) {
-    auto surface = IMG_Load(path.c_str());
-    if (!surface)
+    auto* surface = IMG_Load(path.c_str());
+    if (!surface) {
+        fmt::print("IMG_Load({}) failed: {}\n", path, SDL_GetError());
         return {};
+    }
 
     auto image = load_from_sdl_surface(surface);
     SDL_FreeSurface(surface);
diff --git a/Essa/LLGL/Window/AbstractOpenGLHelper.hpp b/Essa/LLGL/Window/AbstractOpenGLHelper.hpp
index b7c4c044..53367520 100644
--- a/Essa/LLGL/Window/AbstractOpenGLHelper.hpp
+++ b/Essa/LLGL/Window/AbstractOpenGLHelper.hpp
@@ -21,6 +21,7 @@ class OpenGL {
     ADD_OPENGL_FUNCTION(GenTextures)
     ADD_OPENGL_FUNCTION(TexImage2D)
     ADD_OPENGL_FUNCTION(FramebufferTexture)
+    ADD_OPENGL_FUNCTION(FramebufferTexture2D)
     ADD_OPENGL_FUNCTION(GetTexImage)
 
     ADD_OPENGL_FUNCTION(BufferData)
diff --git a/Essa/LLGL/Window/CMakeLists.txt b/Essa/LLGL/Window/CMakeLists.txt
index 0844af06..004ba6e1 100644
--- a/Essa/LLGL/Window/CMakeLists.txt
+++ b/Essa/LLGL/Window/CMakeLists.txt
@@ -7,4 +7,11 @@ set(SOURCES
     Window.cpp
 )
 add_llgl_library(Window window)
-target_link_libraries(LLGL-Window Util SDL2 Xrender)
+if(NOT EMSCRIPTEN) # FIXME: if(LINUX)
+    set(X11_LIBS Xrender)
+endif()
+target_link_libraries(LLGL-Window Util SDL2 ${X11_LIBS})
+if(EMSCRIPTEN)
+    target_compile_options(LLGL-Window PUBLIC "SHELL:-s USE_SDL=2")
+    target_link_options(LLGL-Window PUBLIC "SHELL:-s MAX_WEBGL_VERSION=2 -s USE_WEBGL2=1 -s MIN_WEBGL_VERSION=2 -s FULL_ES3=1")
+endif()
diff --git a/Essa/LLGL/Window/Impls/SDLHelpers.cpp b/Essa/LLGL/Window/Impls/SDLHelpers.cpp
index 69dc2e99..b073cbef 100644
--- a/Essa/LLGL/Window/Impls/SDLHelpers.cpp
+++ b/Essa/LLGL/Window/Impls/SDLHelpers.cpp
@@ -1,15 +1,19 @@
 #include "SDLHelpers.hpp"
 
 #include <EssaUtil/ScopeGuard.hpp>
+#ifndef __EMSCRIPTEN__
 #include <GL/glx.h>
 #include <GL/glxext.h>
+#endif
 #include <SDL2/SDL_error.h>
 #include <SDL2/SDL_events.h>
 #include <SDL2/SDL_hints.h>
 #include <SDL2/SDL_syswm.h>
 #include <SDL2/SDL_video.h>
+#ifndef __EMSCRIPTEN__
 #include <X11/Xlib.h>
 #include <X11/extensions/Xrender.h>
+#endif
 #include <cassert>
 #include <fmt/core.h>
 #include <fmt/format.h>
diff --git a/Essa/LLGL/Window/Impls/SDLWindow.cpp b/Essa/LLGL/Window/Impls/SDLWindow.cpp
index adf33d99..52c1eddb 100644
--- a/Essa/LLGL/Window/Impls/SDLWindow.cpp
+++ b/Essa/LLGL/Window/Impls/SDLWindow.cpp
@@ -39,6 +39,10 @@ void Window::create_impl(Util::Size2u size, Util::UString const& title, WindowSe
 
     initialized = true;
 
+#ifdef __EMSCRIPTEN__
+    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 2);
+    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 0);
+#else
     // Note: Remember to add these attributes to GLX in transparent window implementation
     SDL_GL_SetAttribute(SDL_GL_ACCELERATED_VISUAL, 1);
     SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
@@ -49,6 +53,7 @@ void Window::create_impl(Util::Size2u size, Util::UString const& title, WindowSe
     SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
     SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
     SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
+#endif
 
     uint32_t sdl_flags = SDLHelpers::llgl_window_flags_to_sdl(settings.flags);
     if (has_flag(settings.flags, WindowFlags::TransparentBackground)) {
@@ -80,10 +85,14 @@ void Window::create_impl(Util::Size2u size, Util::UString const& title, WindowSe
     }
     if (!s_context)
         s_context = SDL_GL_CreateContext(m_data->window);
+    if (!s_context) {
+        fmt::print("Failed to create OpenGL context: {}\n", SDL_GetError());
+    }
     int major, minor;
     SDL_GL_GetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, &major);
     SDL_GL_GetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, &minor);
     std::cout << "SDLWindow: Created OpenGL context version " << major << "." << minor << std::endl;
+    std::cout << "GL_VERSION=" << glGetString(GL_VERSION) << std::endl;
     set_active();
 }
 
diff --git a/Essa/LLGL/Window/Window.hpp b/Essa/LLGL/Window/Window.hpp
index f1b23bf1..2873411f 100644
--- a/Essa/LLGL/Window/Window.hpp
+++ b/Essa/LLGL/Window/Window.hpp
@@ -14,7 +14,7 @@
 namespace llgl {
 
 namespace Detail {
-class SDLWindowData;
+struct SDLWindowData;
 }
 
 class Window {
diff --git a/EssaUtil/CMakeLists.txt b/EssaUtil/CMakeLists.txt
index 2f4cd2a8..f116e24e 100644
--- a/EssaUtil/CMakeLists.txt
+++ b/EssaUtil/CMakeLists.txt
@@ -27,7 +27,4 @@ essautil_setup_target(Util)
 install(TARGETS Util EXPORT Essa DESTINATION lib)
 target_link_libraries(Util PUBLIC fmt::fmt)
 
-# FIXME: This breaks build of eml/AST.cpp somewhere in Value::string()
-target_compile_options(Util PRIVATE -Wno-restrict)
-
 add_subdirectory(Tests)
diff --git a/EssaUtil/Config.hpp b/EssaUtil/Config.hpp
index d484f781..620b50b2 100644
--- a/EssaUtil/Config.hpp
+++ b/EssaUtil/Config.hpp
@@ -24,6 +24,8 @@ constexpr bool UNREACHABLE = false;
 
 // https://en.cppreference.com/w/cpp/utility/variant/visit
 template<class... Ts> struct Overloaded : Ts... {
+    Overloaded(Ts... ts)
+        : Ts(std::forward<Ts>(ts))... { }
     using Ts::operator()...;
 };
 
diff --git a/EssaUtil/CoordinateSystem/GeoCoords.cpp b/EssaUtil/CoordinateSystem/GeoCoords.cpp
index 49bfa615..574eebe8 100644
--- a/EssaUtil/CoordinateSystem/GeoCoords.cpp
+++ b/EssaUtil/CoordinateSystem/GeoCoords.cpp
@@ -1,5 +1,10 @@
 #include "GeoCoords.hpp"
 
+// M_PIf is a GCC extension, define it for other compilers
+#ifndef M_PIf
+#    define M_PIf ((float)M_PI)
+#endif
+
 namespace Util {
 
 GeoCoords GeoCoords::normalized() const {
diff --git a/EssaUtil/Error.hpp b/EssaUtil/Error.hpp
index 7e730949..a0ac5069 100644
--- a/EssaUtil/Error.hpp
+++ b/EssaUtil/Error.hpp
@@ -159,7 +159,7 @@ template<typename T, typename... ErrorTypes> class [[nodiscard]] ErrorOr : publi
 
     auto location() const { return m_location; }
 
-    void dump(std::string_view header, CppSourceLocation loc = CppSourceLocation::current()) const {
+    void dump(std::string_view header, [[maybe_unused]] CppSourceLocation loc = CppSourceLocation::current()) const {
         if (is_error()) {
             fmt::print("\e[31;1m{}\e[m", header);
             std::visit(
@@ -171,10 +171,12 @@ template<typename T, typename... ErrorTypes> class [[nodiscard]] ErrorOr : publi
                 },
                 *this
             );
+#ifndef __EMSCRIPTEN__
             fmt::print("\e[m\n");
             fmt::print("  at {}\n", CppSourceLocation { location() });
             fmt::print("  ...\n");
             fmt::print("  at {}\n", loc);
+#endif
         }
     }
 
@@ -211,7 +213,7 @@ template<typename... ErrorTypes> class [[nodiscard]] ErrorOr<void, ErrorTypes...
 };
 
 struct OsError {
-    error_t error;
+    int error;
     std::string_view function;
 };
 
diff --git a/EssaUtil/Is.hpp b/EssaUtil/Is.hpp
index 642fd258..2d2959f3 100644
--- a/EssaUtil/Is.hpp
+++ b/EssaUtil/Is.hpp
@@ -4,6 +4,8 @@
 
 namespace Util {
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Waddress"
 template<class ExpectedT, class T>
     requires(std::is_base_of_v<T, ExpectedT>) bool
 is(T const& t) {
@@ -12,5 +14,6 @@ is(T const& t) {
 
     return dynamic_cast<ExpectedT const*>(&t);
 }
+#pragma GCC diagnostic pop
 
 }
diff --git a/EssaUtil/Stream/File.cpp b/EssaUtil/Stream/File.cpp
index 7b70324e..2fc429e6 100644
--- a/EssaUtil/Stream/File.cpp
+++ b/EssaUtil/Stream/File.cpp
@@ -89,7 +89,7 @@ OsErrorOr<size_t> ReadableFileStream::read(std::span<uint8_t> data) {
     // TODO: Buffering
     auto result = ::read(fd(), data.data(), data.size_bytes());
     if (result < 0) {
-        return OsError { .error = static_cast<error_t>(-result), .function = "FileStream::read_all" };
+        return OsError { .error = static_cast<int>(-result), .function = "FileStream::read_all" };
     }
     if (result == 0) {
         m_eof = true;
@@ -115,7 +115,7 @@ OsErrorOr<size_t> WritableFileStream::write(std::span<uint8_t const> data) {
     // TODO: Buffering
     auto result = ::write(fd(), data.data(), data.size_bytes());
     if (result < 0) {
-        return OsError { .error = static_cast<error_t>(-result), .function = "FileStream::write_all" };
+        return OsError { .error = static_cast<int>(-result), .function = "FileStream::write_all" };
     }
     return static_cast<size_t>(result);
 }
diff --git a/EssaUtil/Testing.hpp b/EssaUtil/Testing.hpp
index 18904db3..c471e4e8 100644
--- a/EssaUtil/Testing.hpp
+++ b/EssaUtil/Testing.hpp
@@ -16,6 +16,8 @@ using namespace Util;
 
 template<class T> struct FormatIfFormattable {
     T const& t;
+    FormatIfFormattable(T const& t_)
+        : t(t_) { }
 };
 
 namespace fmt {
diff --git a/EssaUtil/Tests/CMakeLists.txt b/EssaUtil/Tests/CMakeLists.txt
index ff992009..ed1e266d 100644
--- a/EssaUtil/Tests/CMakeLists.txt
+++ b/EssaUtil/Tests/CMakeLists.txt
@@ -7,7 +7,10 @@ essautil_add_test(GenericParser LIBS Util)
 essautil_add_test(Matrix LIBS Util)
 essautil_add_test(RAIIUtils LIBS Util)
 essautil_add_test(Stream LIBS Util)
-essautil_add_test(Threading LIBS Util)
+if (NOT EMSCRIPTEN)
+    # FIXME: Implement this
+    essautil_add_test(Threading LIBS Util)
+endif()
 essautil_add_test(UString LIBS Util)
 essautil_add_test(UStringBuilder LIBS Util)
 essautil_add_test(UnitDisplay LIBS Util)
diff --git a/EssaUtil/Threading/ThreadPool.hpp b/EssaUtil/Threading/ThreadPool.hpp
index 772d7380..3326bca1 100644
--- a/EssaUtil/Threading/ThreadPool.hpp
+++ b/EssaUtil/Threading/ThreadPool.hpp
@@ -12,6 +12,10 @@
 #include <type_traits>
 #include <vector>
 
+#ifdef __clang__
+#    error todo: implement this
+#endif
+
 namespace Util {
 
 template<class T> class MutexProtected {
diff --git a/EssaUtil/UString.cpp b/EssaUtil/UString.cpp
index 7a54f859..7c54b69d 100644
--- a/EssaUtil/UString.cpp
+++ b/EssaUtil/UString.cpp
@@ -298,11 +298,17 @@ template<> OsErrorOr<double> UString::parse<double>() const { return parse_impl(
 template<> OsErrorOr<long double> UString::parse<long double>() const { return parse_impl(std::stold, *this); }
 
 std::strong_ordering UString::operator<=>(UString const& other) const {
+#ifdef __clang__
+    return std::lexicographical_compare(m_storage, m_storage + m_size, other.m_storage, other.m_storage + other.m_size)
+        ? std::strong_ordering::less
+        : (*this == other ? std::strong_ordering::equal : std::strong_ordering::greater);
+#else
     return std::lexicographical_compare_three_way(m_storage, m_storage + m_size, other.m_storage, other.m_storage + other.m_size);
+#endif
 }
 
 bool UString::operator<(UString const& other) const { return (*this <=> other) == std::strong_ordering::less; }
-bool UString::operator==(UString const& other) const { return (*this <=> other) == std::strong_ordering::equal; }
+bool UString::operator==(UString const& other) const { return size() == other.size() && std::ranges::equal(span(), other.span()); }
 bool UString::operator>(UString const& other) const { return (*this <=> other) == std::strong_ordering::greater; }
 
 UString operator+(UString const& lhs, UString const& rhs) {
diff --git a/cmake/utils.cmake b/cmake/utils.cmake
index fb071492..6d37a6f5 100644
--- a/cmake/utils.cmake
+++ b/cmake/utils.cmake
@@ -44,18 +44,28 @@ function(essautil_setup_target targetname)
         if (ESSA_IS_PRODUCTION)
             set_target_properties(${targetname} PROPERTIES INSTALL_RPATH "${CMAKE_INSTALL_PREFIX}/lib")
         endif()
+        if (EMSCRIPTEN)
+            target_link_options(${targetname} PRIVATE "SHELL:--embed-file ${Essa_SOURCE_DIR}/assets")
+        endif()
     endif()
 
     target_include_directories(${targetname} PUBLIC ${PROJECT_SOURCE_DIR})
 
+    if (NOT EMSCRIPTEN)
+        set(GCC_OPTIONS 
+            -Wno-error=stringop-overflow    # FIXME: fmt on CI doesn't like it for some reason, find a way to workaround it!
+            -Wno-error=restrict             # FIXME: This breaks compilation of EML::value() and some more places
+        )
+    endif()
+
     target_compile_options(${targetname} PRIVATE
         -fdiagnostics-color=always
         -Wall -Wextra -Werror
         -Wnon-virtual-dtor
         -Wno-error=missing-field-initializers       # FIXME: This is buggy (?) for *DrawOptions
         -Wno-error=format                           # FIXME: We don't use formatting anyway except SimulationClock but this breaks mingw build
-        -Wno-error=stringop-overflow                # FIXME: fmt on CI doesn't like it for some reason, find a way to workaround it!
         -Wno-error=deprecated-declarations
+        ${GCC_OPTIONS}
     )
 
     set_property(TARGET ${targetname} PROPERTY CXX_STANDARD 20)
@@ -107,11 +117,15 @@ function(essa_resources targetname dir)
     set(outfile ${CMAKE_CURRENT_BINARY_DIR}/EssaResources.cpp)
     file(WRITE ${outfile} "extern \"C\" { const char* ESSA_RESOURCE_DIR = \"")
     if (ESSA_IS_PRODUCTION)
-        file(APPEND ${outfile} ${CMAKE_INSTALL_PREFIX}/${DEST_PATH})
+        set(resource_dir ${CMAKE_INSTALL_PREFIX}/${DEST_PATH})
     else()
-        file(APPEND ${outfile} ${CMAKE_CURRENT_SOURCE_DIR}/${dir})
+        set(resource_dir ${CMAKE_CURRENT_SOURCE_DIR}/${dir})
     endif()
+    file(APPEND ${outfile} ${resource_dir})
     file(APPEND ${outfile} "\"; }")
 
     target_sources(${targetname} PRIVATE ${outfile})
+    if (EMSCRIPTEN)
+        target_link_options(${targetname} PRIVATE "SHELL:--embed-file ${resource_dir}")
+    endif()
 endfunction()
diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 72ef7854..26ffed1f 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -18,7 +18,9 @@ add_example("essa-gui/image-widget")
 add_example("essa-gui/listboxes")
 add_example("essa-gui/message-box-multiline")
 add_example("essa-gui/multiple-windows")
-add_example("essa-gui/passthrough" LIBS Xfixes X11)
+if(NOT EMSCRIPTEN)
+    add_example("essa-gui/passthrough" LIBS Xfixes X11)
+endif()
 add_example("essa-gui/progressbars")
 add_example("essa-gui/rich-text")
 add_example("essa-gui/scrollable-container")