diff --git a/CMakeLists.txt b/CMakeLists.txt
index ea40581..502e1e4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,7 +4,6 @@ project(cruft-vulkan CXX)
 
 
 ###############################################################################
-find_package (Vulkan REQUIRED)
 find_package (PythonInterp 3 REQUIRED)
 find_package (glfw3 REQUIRED)
 
@@ -15,6 +14,7 @@ endif ()
 
 
 ###############################################################################
+file (MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/icd")
 include_directories ("${CMAKE_CURRENT_BINARY_DIR}")
 
 
@@ -31,6 +31,7 @@ endif()
 add_custom_command (
 OUTPUT
     "${CMAKE_CURRENT_BINARY_DIR}/vk.hpp"
+    "${CMAKE_CURRENT_BINARY_DIR}/icd/dispatch.cpp"
 COMMENT
     "[spec.py] vk.hpp"
 COMMAND
@@ -38,6 +39,7 @@ COMMAND
     "${CMAKE_CURRENT_SOURCE_DIR}/tools/spec.py"
     "--src" "${CMAKE_CURRENT_SOURCE_DIR}/specs/xml/vk.xml"
     "--dst" "${CMAKE_CURRENT_BINARY_DIR}/vk.hpp"
+    "--dispatch" "${CMAKE_CURRENT_BINARY_DIR}/icd/dispatch.cpp"
     "--platform" "${VK_PLATFORM}"
 DEPENDS
     "${CMAKE_CURRENT_SOURCE_DIR}/tools/spec.py"
@@ -47,7 +49,27 @@ DEPENDS
 include_directories("${CMAKE_CURRENT_SOURCE_DIR}/specs/include/vulkan")
 
 
+###############################################################################
+if (WIN32)
+    set(VK_LOADER_VENDOR win32)
+elseif (LINUX)
+    set(VK_LOADER_VENDOR posix)
+else ()
+    message (FATAL_ERROR "unhandled vk-loader platform")
+endif()
+
+
 ##-----------------------------------------------------------------------------
+add_library (cruft-vk-icd STATIC
+    ${CMAKE_CURRENT_BINARY_DIR}/icd/dispatch.cpp
+    icd/vendor.hpp
+    icd/vendor.cpp
+    icd/vendor_${VK_LOADER_VENDOR}
+)
+
+target_link_libraries (cruft-vk-icd cruft-json cruft)
+
+###############################################################################
 list (APPEND sources
     vk.hpp
 
@@ -107,7 +129,7 @@ list (APPEND sources
 
 ##-----------------------------------------------------------------------------
 add_library (cruft-vk STATIC ${sources})
-target_link_libraries (cruft-vk cruft vulkan)
+target_link_libraries (cruft-vk cruft-vk-icd cruft)
 
 
 ###############################################################################
diff --git a/icd/vendor.cpp b/icd/vendor.cpp
new file mode 100644
index 0000000..573c6a4
--- /dev/null
+++ b/icd/vendor.cpp
@@ -0,0 +1,34 @@
+#include "vendor.hpp"
+
+#include <cruft/json/tree.hpp>
+
+using cruft::vk::icd::vendor;
+
+
+template <>
+cruft::vk::icd::icd_t
+json::tree::io<cruft::vk::icd::icd_t>::deserialise (json::tree::node const &obj)
+{
+    return {
+        .file_format_version = obj["'file_format_version"].as_string (),
+        .icd = {
+            .library_path = obj["ICD"]["library_path"].as_string ().native (),
+            .api_version = obj["ICD"]["api_version"].as_string (),
+        },
+    };
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+vendor::vendor (icd_t const &_icd):
+    vendor (cruft::library (_icd.icd.library_path))
+{ ; }
+
+
+//-----------------------------------------------------------------------------
+vendor::vendor (::cruft::library &&_library)
+    : m_library (std::move (_library))
+    , m_get_proc (m_library.symbol<decltype(m_get_proc)> ("vk_icdGetInstanceProcAddr"))
+{
+    vtable.CreateInstance = reinterpret_cast<decltype(vtable.CreateInstance)> (m_get_proc (nullptr, "vkCreateInstance"));
+}
diff --git a/icd/vendor.hpp b/icd/vendor.hpp
new file mode 100644
index 0000000..5b03021
--- /dev/null
+++ b/icd/vendor.hpp
@@ -0,0 +1,40 @@
+#pragma once
+
+#include "vk.hpp"
+
+#include <cruft/util/library.hpp>
+
+#include <string>
+#include <experimental/filesystem>
+
+
+namespace cruft::vk::icd {
+    struct icd_t {
+        std::string file_format_version;
+        struct {
+            std::experimental::filesystem::path library_path;
+            std::string api_version;
+        } icd;
+    };
+
+
+    std::vector<icd_t>
+    enumerate (void);
+
+
+    class vendor {
+    public:
+        vendor (icd_t const&);
+        vendor (::cruft::library &&);
+
+        struct vtable_t {
+            VkResult (*CreateInstance) (const VkInstanceCreateInfo*, const VkAllocationCallbacks*, VkInstance*) noexcept;
+        } vtable;
+
+    private:
+        using get_proc_t = void* (*)(VkInstance, char const*);
+
+        ::cruft::library m_library;
+        get_proc_t const m_get_proc;
+    };
+}
\ No newline at end of file
diff --git a/icd/vendor_posix.cpp b/icd/vendor_posix.cpp
new file mode 100644
index 0000000..e69de29
diff --git a/icd/vendor_win32.cpp b/icd/vendor_win32.cpp
new file mode 100644
index 0000000..f4305f6
--- /dev/null
+++ b/icd/vendor_win32.cpp
@@ -0,0 +1,51 @@
+#include "vendor.hpp"
+
+#include <cruft/json/tree.hpp>
+
+#include <cruft/util/io.hpp>
+#include <cruft/util/log.hpp>
+#include <cruft/util/win32/registry.hpp>
+#include <cruft/util/win32/except.hpp>
+
+
+///////////////////////////////////////////////////////////////////////////////
+std::vector<cruft::vk::icd::icd_t>
+cruft::vk::icd::enumerate()
+{
+    std::vector<icd_t> res;
+
+    win32::key root (HKEY_LOCAL_MACHINE, "System\\CurrentControlSet\\Control\\Class\\");
+
+    for (auto &&adapter: root.subkeys ()) {
+        for (auto &&device: adapter.subkeys ()) {
+            // device keys must be of the form '000X'
+            auto const name = device.name ();
+            if (name.size () != 4 ||
+                name[0] != '0' ||
+                name[1] != '0' ||
+                name[2] != '0' ||
+                !std::isdigit(name[3]))
+            {
+                continue;
+            }
+
+            // 'VulkanDriverName' contains the JSON for the ICD data. Parse
+            // this and add to the list. If we encounter an error then
+            // quietly  drop it.
+            try {
+                auto const path = device.data<std::string> ("VulkanDriverName");
+                auto const text = cruft::slurp<char> (path);
+                auto const jobj = json::tree::parse (cruft::view{text});
+                auto const data = from_json<icd_t> (*jobj);
+
+                res.push_back (data);
+            } catch (win32::error const&) {
+                ;
+            } catch (std::exception const &e) {
+                LOG_WARNING ("error loading Vulkan ICD manifest, %!", e.what ());
+            }
+        }
+    }
+
+    return res;
+}
diff --git a/tools/info.cpp b/tools/info.cpp
index 740af7e..229d14e 100644
--- a/tools/info.cpp
+++ b/tools/info.cpp
@@ -16,10 +16,19 @@
 #include <iostream>
 
 
+#include "../icd/vendor.hpp"
+
+
 ///////////////////////////////////////////////////////////////////////////////
 int
 main (int, char**)
 {
+    auto all = cruft::vk::icd::enumerate ();
+    for (auto const &i: all) {
+        cruft::vk::icd::vendor v (i);
+    }
+
+
     std::cout << "available_layers: [ "
               << cruft::make_infix (cruft::vk::instance::available_layers ())
               << " ]\n";
diff --git a/tools/spec.py b/tools/spec.py
index e72b586..059ee5a 100644
--- a/tools/spec.py
+++ b/tools/spec.py
@@ -652,6 +652,7 @@ if __name__ == '__main__':
     parser = argparse.ArgumentParser(description='Transform XML API specification into C++ headers')
     parser.add_argument('--src', type=str, help='the path to the XML file to transform')
     parser.add_argument('--dst', type=str, help='the output path for the result')
+    parser.add_argument('--dispatch', type=str, help="the output path for function dispatch")
     parser.add_argument(
         '--platform',
         type=str,
@@ -662,7 +663,6 @@ if __name__ == '__main__':
     args = parser.parse_args()
 
     src = open(args.src, 'r')
-    dst = open(args.dst, 'w')
 
     tree = ET.parse(src)
     root = tree.getroot()
@@ -689,14 +689,29 @@ if __name__ == '__main__':
     extensions = ["VK_KHR_swapchain", "VK_EXT_debug_report", "VK_KHR_external_memory"]
     q = reg.serialise(args.platform)
 
+    with open(args.dst, 'w') as dst:
+        dst.write("#pragma once\n")
+        dst.write('extern "C" {\n')
+        for obj in q:
+            dst.write(obj.declare())
+            dst.write('\n')
+            dst.write(obj.define(reg))
+            dst.write('\n')
+        dst.write('}\n')
 
-    dst.write("#pragma once\n")
-    dst.write('extern "C" {\n')
-    for obj in q:
-        dst.write(obj.declare())
-        dst.write('\n')
-        dst.write(obj.define(reg))
-        dst.write('\n')
-    dst.write('}\n')
+    with open(args.dispatch, 'w') as dispatch:
+        dispatch.write("""
+        #include "vk.hpp"
+        #include <cruft/util/debug.hpp>
 
-    #write_types(dst, types)
+        #pragma GCC diagnostic ignored "-Wunused-parameter"
+        """)
+        for obj in q:
+            if not isinstance(obj, command):
+                continue
+
+            dispatch.write(f"""
+            extern "C" {obj.result} {rename(obj.name)} ({", ".join(obj.params)}) noexcept {{
+                unimplemented ();
+            }}
+            """)