diff --git a/cmake/avendish.clap.cmake b/cmake/avendish.clap.cmake
index feac702b..623e5ce3 100644
--- a/cmake/avendish.clap.cmake
+++ b/cmake/avendish.clap.cmake
@@ -43,10 +43,10 @@ function(avnd_make_clap)
     NEWLINE_STYLE LF
   )
 
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
-      "${AVND_MAIN_FILE}"
       "${CMAKE_BINARY_DIR}/${AVND_C_NAME}_clap.cpp"
   )
 
diff --git a/cmake/avendish.cmake b/cmake/avendish.cmake
index be0663ff..5f81c88c 100644
--- a/cmake/avendish.cmake
+++ b/cmake/avendish.cmake
@@ -47,6 +47,10 @@ function(_avnd_dispatch_backend backend)
   if(DEFINED ${_flag} AND NOT ${${_flag}})
     return()
   endif()
+  # Compute the prototype's object-pull-in line once; the called backend's
+  # configure_file picks up AVND_MAIN_IMPORT from this (calling) scope.
+  cmake_parse_arguments(AVND "" "MAIN_FILE;C_NAME" "" ${ARGN})
+  avnd_main_import(AVND_MAIN_IMPORT "${AVND_MAIN_FILE}" "${AVND_C_NAME}")
   cmake_language(CALL "avnd_make_${backend}" ${ARGN})
 endfunction()
 
@@ -259,6 +263,7 @@ add_library(avnd_dummy_lib OBJECT "${AVND_SOURCE_DIR}/src/dummy.cpp")
 include(avendish.dependencies)
 include(avendish.disableexceptions)
 include(avendish.sources)
+include(avendish.modules)
 include(avendish.tools)
 
 include(avendish.ui.qt)
@@ -286,7 +291,7 @@ function(avnd_register)
     add_library("${AVND_TARGET}" STATIC $<TARGET_OBJECTS:avnd_dummy_lib>)
   endif()
 
-  target_sources("${AVND_TARGET}" PRIVATE "${AVND_MAIN_FILE}")
+  avnd_add_object_to_base("${AVND_TARGET}" "${AVND_MAIN_FILE}")
   if(AVND_COMPILE_OPTIONS)
     target_compile_options("${AVND_TARGET}" PUBLIC "${AVND_COMPILE_OPTIONS}")
   endif()
diff --git a/cmake/avendish.dump.cmake b/cmake/avendish.dump.cmake
index 338beba1..15a29e2d 100644
--- a/cmake/avendish.dump.cmake
+++ b/cmake/avendish.dump.cmake
@@ -15,6 +15,7 @@ function(avnd_make_dump)
 
   string(MAKE_C_IDENTIFIER "${AVND_MAIN_CLASS}" MAIN_OUT_FILE)
 
+  avnd_main_import(AVND_MAIN_IMPORT "${AVND_MAIN_FILE}" "${AVND_C_NAME}")
   configure_file(
     "${AVND_SOURCE_DIR}/include/avnd/binding/dump/prototype.cpp.in"
     "${CMAKE_BINARY_DIR}/${MAIN_OUT_FILE}_dump.cpp"
@@ -31,10 +32,10 @@ function(avnd_make_dump)
       RUNTIME_OUTPUT_DIRECTORY dump
   )
 
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
-      "${AVND_MAIN_FILE}"
       "${CMAKE_BINARY_DIR}/${MAIN_OUT_FILE}_dump.cpp"
   )
 
diff --git a/cmake/avendish.example.cmake b/cmake/avendish.example.cmake
index df8a507f..33ec0fae 100644
--- a/cmake/avendish.example.cmake
+++ b/cmake/avendish.example.cmake
@@ -1,7 +1,7 @@
 include(CTest)
 
 function(avnd_make_example_host)
-  cmake_parse_arguments(AVND "" "TARGET;MAIN_FILE;MAIN_CLASS" "" ${ARGN})
+  cmake_parse_arguments(AVND "" "TARGET;MAIN_FILE;MAIN_CLASS;C_NAME" "" ${ARGN})
 
   set(AVND_FX_TARGET "${AVND_TARGET}_example_host")
   if(TARGET "${AVND_FX_TARGET}")
@@ -11,6 +11,7 @@ function(avnd_make_example_host)
 
   string(MAKE_C_IDENTIFIER "${AVND_MAIN_CLASS}" MAIN_OUT_FILE)
 
+  avnd_main_import(AVND_MAIN_IMPORT "${AVND_MAIN_FILE}" "${AVND_C_NAME}")
   configure_file(
     "${AVND_SOURCE_DIR}/include/avnd/binding/example/prototype.cpp.in"
     "${CMAKE_BINARY_DIR}/${MAIN_OUT_FILE}_example_host.cpp"
@@ -25,6 +26,7 @@ function(avnd_make_example_host)
     PROPERTIES
       RUNTIME_OUTPUT_DIRECTORY example
   )
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
diff --git a/cmake/avendish.fuzz.cmake b/cmake/avendish.fuzz.cmake
index b04b8cbb..42de63b9 100644
--- a/cmake/avendish.fuzz.cmake
+++ b/cmake/avendish.fuzz.cmake
@@ -47,10 +47,10 @@ function(avnd_make_fuzz)
       RUNTIME_OUTPUT_DIRECTORY fuzz
   )
 
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
-      "${AVND_MAIN_FILE}"
       "${CMAKE_BINARY_DIR}/${MAIN_OUT_FILE}_fuzz.cpp"
   )
 
diff --git a/cmake/avendish.godot.cmake b/cmake/avendish.godot.cmake
index d984ca94..d193e9a8 100644
--- a/cmake/avendish.godot.cmake
+++ b/cmake/avendish.godot.cmake
@@ -173,10 +173,10 @@ function(avnd_make_godot)
     PUBLIC
       cxx_std_23
   )
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
-      "${AVND_MAIN_FILE}"
       "${CMAKE_BINARY_DIR}/${MAIN_OUT_FILE}_godot.cpp"
       ${AVND_GODOT_SOURCES}
   )
diff --git a/cmake/avendish.gstreamer.cmake b/cmake/avendish.gstreamer.cmake
index 11d2f0dc..c3d002dd 100644
--- a/cmake/avendish.gstreamer.cmake
+++ b/cmake/avendish.gstreamer.cmake
@@ -63,10 +63,10 @@ function(avnd_make_gstreamer)
       ARCHIVE_OUTPUT_DIRECTORY gstreamer
   )
 
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
-      "${AVND_MAIN_FILE}"
       "${AVND_SOURCE_DIR}/include/avnd/binding/gstreamer/audio_source.hpp"
       "${AVND_SOURCE_DIR}/include/avnd/binding/gstreamer/audio_sink.hpp"
       "${AVND_SOURCE_DIR}/include/avnd/binding/gstreamer/audio_filter.hpp"
diff --git a/cmake/avendish.max.cmake b/cmake/avendish.max.cmake
index 44f5f622..3aed5481 100644
--- a/cmake/avendish.max.cmake
+++ b/cmake/avendish.max.cmake
@@ -123,10 +123,10 @@ function(avnd_make_max)
       AVND_C_NAME "${AVND_C_NAME}"
   )
 
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
-      "${AVND_MAIN_FILE}"
       "${CMAKE_BINARY_DIR}/${MAIN_OUT_FILE}_max.cpp"
 
       "${AVND_SOURCE_DIR}/include/avnd/binding/max/all.hpp"
diff --git a/cmake/avendish.modules.cmake b/cmake/avendish.modules.cmake
new file mode 100644
index 00000000..5019bb61
--- /dev/null
+++ b/cmake/avendish.modules.cmake
@@ -0,0 +1,60 @@
+# C++20 module support.
+#
+# A user object can be written as a module (`export module <c_name>; import halp;`)
+# in a .cppm MAIN_FILE instead of a header. The per-backend prototype then either
+# `#include`s the header or `import`s the module -- only that one line differs.
+#
+# GCC requires a module BMI's exception/rtti dialect to match every consumer
+# exactly (a mismatch is a hard "Bad file data" error), and avendish backends
+# disagree: dump/python/ossia build with exceptions+rtti, while the plugin
+# backends (clap/pd/max/vst3/vintage/gstreamer/wasm/example) build with
+# -fno-exceptions -fno-rtti. So a single shared halp BMI cannot serve all of
+# them. Instead the slim halp module and the user object are compiled *into each
+# backend target*, inheriting that backend's dialect. Both are one small object,
+# so the duplication is cheap and every backend stays self-contained.
+#
+# Requirements for the module path: a generator with module support (Ninja --
+# the Makefiles generator drops -fmodules) and -DCMAKE_CXX_SCAN_FOR_MODULES=ON
+# so the generated prototype's `import` is scanned for its BMI dependency.
+
+# Line a prototype uses to pull in the user object.
+function(avnd_main_import out main_file c_name)
+  if("${main_file}" MATCHES "\\.cppm$")
+    set("${out}" "import ${c_name};" PARENT_SCOPE)
+  else()
+    set("${out}" "#include <${main_file}>" PARENT_SCOPE)
+  endif()
+endfunction()
+
+# Add the user object to its per-object base library. A header compiles once here
+# as before; a .cppm is compiled per-backend instead (see below), so there is
+# nothing to add to the base for the module case.
+function(avnd_add_object_to_base base main_file)
+  if(NOT "${main_file}" MATCHES "\\.cppm$")
+    target_sources(${base} PRIVATE "${main_file}")
+  endif()
+endfunction()
+
+# Make a backend target consume the user object. For a module, compile the slim
+# halp module and the user .cppm into the backend itself, in the backend's own
+# dialect, so the prototype's `import` resolves against a BMI built with matching
+# exception/rtti flags. For a header, compile it into the backend TU as before.
+function(avnd_add_object_to_backend backend base main_file)
+  if("${main_file}" MATCHES "\\.cppm$")
+    # The halp module lives in the avendish tree, the user object wherever the
+    # caller put it; a CXX_MODULES file set requires every file under one of its
+    # base dirs, so cover both.
+    get_filename_component(_avnd_mf_dir "${main_file}" DIRECTORY)
+    target_sources(${backend}
+      PRIVATE
+        FILE_SET avnd_modules TYPE CXX_MODULES
+        BASE_DIRS "${AVND_SOURCE_DIR}/include/halp" "${_avnd_mf_dir}"
+        FILES
+          "${AVND_SOURCE_DIR}/include/halp/halp.cppm"
+          "${main_file}"
+    )
+    target_compile_features(${backend} PRIVATE cxx_std_23)
+  else()
+    target_sources(${backend} PRIVATE "${main_file}")
+  endif()
+endfunction()
diff --git a/cmake/avendish.ossia.cmake b/cmake/avendish.ossia.cmake
index f88962b7..956b8213 100644
--- a/cmake/avendish.ossia.cmake
+++ b/cmake/avendish.ossia.cmake
@@ -36,6 +36,7 @@ function(avnd_make_ossia)
 
   string(MAKE_C_IDENTIFIER "${AVND_MAIN_CLASS}" MAIN_OUT_FILE)
 
+  avnd_main_import(AVND_MAIN_IMPORT "${AVND_MAIN_FILE}" "${AVND_C_NAME}")
   configure_file(
     "${AVND_SOURCE_DIR}/include/avnd/binding/ossia/prototype.cpp.in"
     "${CMAKE_BINARY_DIR}/${MAIN_OUT_FILE}_ossia.cpp"
@@ -50,10 +51,10 @@ function(avnd_make_ossia)
       RUNTIME_OUTPUT_DIRECTORY ossia
   )
 
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
-      "${AVND_MAIN_FILE}"
       "${CMAKE_BINARY_DIR}/${MAIN_OUT_FILE}_ossia.cpp"
   )
 
diff --git a/cmake/avendish.pd.cmake b/cmake/avendish.pd.cmake
index d14b62e9..aa4617d6 100644
--- a/cmake/avendish.pd.cmake
+++ b/cmake/avendish.pd.cmake
@@ -68,10 +68,10 @@ function(avnd_make_pd)
       ARCHIVE_OUTPUT_DIRECTORY pd
   )
 
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
-      "${AVND_MAIN_FILE}"
       "${CMAKE_BINARY_DIR}/${MAIN_OUT_FILE}_pd.cpp"
   )
 
diff --git a/cmake/avendish.python.cmake b/cmake/avendish.python.cmake
index f48be6f9..bec26656 100644
--- a/cmake/avendish.python.cmake
+++ b/cmake/avendish.python.cmake
@@ -54,10 +54,10 @@ function(avnd_make_python)
     )
   endif()
 
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
-      "${AVND_MAIN_FILE}"
       "${CMAKE_BINARY_DIR}/${MAIN_OUT_FILE}_python.cpp"
   )
 
diff --git a/cmake/avendish.standalone.cmake b/cmake/avendish.standalone.cmake
index d2c1d0ff..e22e5c7a 100644
--- a/cmake/avendish.standalone.cmake
+++ b/cmake/avendish.standalone.cmake
@@ -80,10 +80,10 @@ function(avnd_make_standalone)
         RUNTIME_OUTPUT_DIRECTORY standalone
     )
   endif()
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
-      "${AVND_MAIN_FILE}"
       "${CMAKE_BINARY_DIR}/${MAIN_OUT_FILE}_standalone.cpp"
   )
 
diff --git a/cmake/avendish.touchdesigner.cmake b/cmake/avendish.touchdesigner.cmake
index 0408f167..b584bf82 100644
--- a/cmake/avendish.touchdesigner.cmake
+++ b/cmake/avendish.touchdesigner.cmake
@@ -69,10 +69,10 @@ function(avnd_make_touchdesigner)
 
   add_library(${AVND_FX_TARGET} MODULE)
 
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
-      "${AVND_MAIN_FILE}"
       "${CMAKE_BINARY_DIR}/${MAIN_OUT_FILE}_touchdesigner.cpp"
       ${AVND_TD_SOURCES}
   )
diff --git a/cmake/avendish.vintage.cmake b/cmake/avendish.vintage.cmake
index 1768eade..2aa2c848 100644
--- a/cmake/avendish.vintage.cmake
+++ b/cmake/avendish.vintage.cmake
@@ -27,10 +27,10 @@ function(avnd_make_vintage)
     NEWLINE_STYLE LF
   )
 
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
-      "${AVND_MAIN_FILE}"
       "${CMAKE_BINARY_DIR}/${AVND_C_NAME}_vintage.cpp"
   )
 
diff --git a/cmake/avendish.vst3.cmake b/cmake/avendish.vst3.cmake
index 27c9d501..8ced8789 100644
--- a/cmake/avendish.vst3.cmake
+++ b/cmake/avendish.vst3.cmake
@@ -50,10 +50,10 @@ function(avnd_make_vst3)
     NEWLINE_STYLE LF
   )
 
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
-      "${AVND_MAIN_FILE}"
       "${CMAKE_BINARY_DIR}/${AVND_C_NAME}_vst3.cpp"
   )
 
diff --git a/cmake/avendish.wasm.cmake b/cmake/avendish.wasm.cmake
index 3659b5e9..f00865a8 100644
--- a/cmake/avendish.wasm.cmake
+++ b/cmake/avendish.wasm.cmake
@@ -69,10 +69,10 @@ function(avnd_make_wasm)
       AVND_C_NAME "${AVND_C_NAME}"
   )
 
+  avnd_add_object_to_backend(${AVND_FX_TARGET} ${AVND_TARGET} "${AVND_MAIN_FILE}")
   target_sources(
     ${AVND_FX_TARGET}
     PRIVATE
-      "${AVND_MAIN_FILE}"
       "${CMAKE_BINARY_DIR}/${MAIN_OUT_FILE}_wasm.cpp"
   )
 
diff --git a/include/avnd/binding/clap/prototype.cpp.in b/include/avnd/binding/clap/prototype.cpp.in
index 5698c61c..46a06500 100644
--- a/include/avnd/binding/clap/prototype.cpp.in
+++ b/include/avnd/binding/clap/prototype.cpp.in
@@ -1,9 +1,10 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 
-#include <@AVND_MAIN_FILE@>
 #include <avnd/binding/clap/audio_effect.hpp>
 #include <avnd/binding/clap/configure.hpp>
 
+@AVND_MAIN_IMPORT@
+
 // clang-format off
 using plug_type = decltype(avnd::configure<avnd_clap::config, @AVND_MAIN_CLASS@>())::type;
 using effect_type = avnd_clap::SimpleAudioEffect<plug_type>;
diff --git a/include/avnd/binding/dump/prototype.cpp.in b/include/avnd/binding/dump/prototype.cpp.in
index cbeca65a..d1c438d4 100644
--- a/include/avnd/binding/dump/prototype.cpp.in
+++ b/include/avnd/binding/dump/prototype.cpp.in
@@ -13,7 +13,7 @@ struct config
 };
 }
 
-#include <@AVND_MAIN_FILE@>
+@AVND_MAIN_IMPORT@
 int main(int argc, char** argv)
 {
   using type = decltype(avnd::configure<dump::config, @AVND_MAIN_CLASS@>())::type;
diff --git a/include/avnd/binding/example/prototype.cpp.in b/include/avnd/binding/example/prototype.cpp.in
index 7bd68fc1..9dce5458 100644
--- a/include/avnd/binding/example/prototype.cpp.in
+++ b/include/avnd/binding/example/prototype.cpp.in
@@ -1,8 +1,9 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 
-#include <@AVND_MAIN_FILE@>
 #include <avnd/binding/example/example_processor.hpp>
 
+@AVND_MAIN_IMPORT@
+
 using type = decltype(avnd::configure<exhs::config, @AVND_MAIN_CLASS@>())::type;
 
 int main()
diff --git a/include/avnd/binding/fuzz/prototype.cpp.in b/include/avnd/binding/fuzz/prototype.cpp.in
index bd4def02..78cd650b 100644
--- a/include/avnd/binding/fuzz/prototype.cpp.in
+++ b/include/avnd/binding/fuzz/prototype.cpp.in
@@ -12,7 +12,7 @@ struct config
 };
 }
 
-#include <@AVND_MAIN_FILE@>
+@AVND_MAIN_IMPORT@
 
 // libFuzzer provides main(); we only supply the per-input entry point.
 extern "C" int LLVMFuzzerTestOneInput(const std::uint8_t* data, std::size_t size)
diff --git a/include/avnd/binding/godot/prototype.cpp.in b/include/avnd/binding/godot/prototype.cpp.in
index a4cc0f44..b18fdc75 100644
--- a/include/avnd/binding/godot/prototype.cpp.in
+++ b/include/avnd/binding/godot/prototype.cpp.in
@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 
 // clang-format off
-#include <@AVND_MAIN_FILE@>
 #include <avnd/binding/godot/configure.hpp>
 #include <avnd/binding/godot/node.hpp>
 
@@ -9,6 +8,8 @@
 #include <godot_cpp/core/defs.hpp>
 #include <godot_cpp/godot.hpp>
 
+@AVND_MAIN_IMPORT@
+
 using type = decltype(avnd::configure<godot_binding::config, @AVND_MAIN_CLASS@>())::type;
 // clang-format on
 
diff --git a/include/avnd/binding/gstreamer/prototype.cpp.in b/include/avnd/binding/gstreamer/prototype.cpp.in
index 3974b778..f91db44c 100644
--- a/include/avnd/binding/gstreamer/prototype.cpp.in
+++ b/include/avnd/binding/gstreamer/prototype.cpp.in
@@ -3,7 +3,7 @@
 // clang-format off
 #include <avnd/binding/gstreamer/element.hpp>
 #include <avnd/binding/gstreamer/configuration.hpp>
-#include <@AVND_MAIN_FILE@>
+@AVND_MAIN_IMPORT@
 
 
 using type = decltype(avnd::configure<gst::config, @AVND_MAIN_CLASS@>())::type;
diff --git a/include/avnd/binding/max/prototype.cpp.in b/include/avnd/binding/max/prototype.cpp.in
index ab913458..c718ffc0 100644
--- a/include/avnd/binding/max/prototype.cpp.in
+++ b/include/avnd/binding/max/prototype.cpp.in
@@ -1,12 +1,13 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 
 // clang-format off
-#include <@AVND_MAIN_FILE@>
 #include <avnd/binding/max/audio_processor.hpp>
 #include <avnd/binding/max/message_processor.hpp>
 #include <avnd/binding/max/configure.hpp>
 #include <avnd/binding/max/jitter_processor.hpp>
 #include "commonsyms.h"
+
+@AVND_MAIN_IMPORT@
 using type = decltype(avnd::configure<max::config, @AVND_MAIN_CLASS@>())::type;
 // clang-format on
 
diff --git a/include/avnd/binding/ossia/prototype.cpp.in b/include/avnd/binding/ossia/prototype.cpp.in
index d385d1bf..82f3c4ca 100644
--- a/include/avnd/binding/ossia/prototype.cpp.in
+++ b/include/avnd/binding/ossia/prototype.cpp.in
@@ -1,9 +1,10 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 
-#include <@AVND_MAIN_FILE@>
 #include <avnd/binding/ossia/all.hpp>
 #include <avnd/binding/ossia/configure.hpp>
 
+@AVND_MAIN_IMPORT@
+
 using type = decltype(avnd::configure<oscr::config, @AVND_MAIN_CLASS@>())::type;
 
 void test_instantiate(ossia::exec_state_facade st)
diff --git a/include/avnd/binding/pd/prototype.cpp.in b/include/avnd/binding/pd/prototype.cpp.in
index 5cefe039..88ab8e89 100644
--- a/include/avnd/binding/pd/prototype.cpp.in
+++ b/include/avnd/binding/pd/prototype.cpp.in
@@ -1,10 +1,11 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 
 // clang-format off
-#include <@AVND_MAIN_FILE@>
 #include <avnd/binding/pd/audio_processor.hpp>
 #include <avnd/binding/pd/message_processor.hpp>
 #include <avnd/binding/pd/configure.hpp>
+
+@AVND_MAIN_IMPORT@
 using type = decltype(avnd::configure<pd::config, @AVND_MAIN_CLASS@>())::type;
 // clang-format on
 
diff --git a/include/avnd/binding/python/prototype.cpp.in b/include/avnd/binding/python/prototype.cpp.in
index 2ff0863a..a3f846e5 100644
--- a/include/avnd/binding/python/prototype.cpp.in
+++ b/include/avnd/binding/python/prototype.cpp.in
@@ -1,9 +1,10 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 
-#include <@AVND_MAIN_FILE@>
 #include <avnd/binding/python/configure.hpp>
 #include <avnd/binding/python/processor.hpp>
 
+@AVND_MAIN_IMPORT@
+
 PYBIND11_MODULE(py@AVND_C_NAME@, m)
 {
   using type = decltype(avnd::configure<python::config, @AVND_MAIN_CLASS@>())::type;
diff --git a/include/avnd/binding/standalone/prototype.cpp.in b/include/avnd/binding/standalone/prototype.cpp.in
index c21a5fa5..fceb57b2 100644
--- a/include/avnd/binding/standalone/prototype.cpp.in
+++ b/include/avnd/binding/standalone/prototype.cpp.in
@@ -6,7 +6,7 @@
 
 #include <thread>
 
-#include <@AVND_MAIN_FILE@>
+@AVND_MAIN_IMPORT@
 
 #if AVND_STANDALONE_QML
 #include <QCommandLineOption>
diff --git a/include/avnd/binding/vintage/prototype.cpp.in b/include/avnd/binding/vintage/prototype.cpp.in
index 5d4af621..5fc12f36 100644
--- a/include/avnd/binding/vintage/prototype.cpp.in
+++ b/include/avnd/binding/vintage/prototype.cpp.in
@@ -1,9 +1,10 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 
-#include <@AVND_MAIN_FILE@>
 #include <avnd/binding/vintage/audio_effect.hpp>
 #include <avnd/binding/vintage/configure.hpp>
 
+@AVND_MAIN_IMPORT@
+
 extern "C"
 AVND_EXPORTED_SYMBOL vintage::Effect* VSTPluginMain(
     vintage::HostCallback cb)
diff --git a/include/avnd/binding/vst3/prototype.cpp.in b/include/avnd/binding/vst3/prototype.cpp.in
index 6e271b2a..b420c9e7 100644
--- a/include/avnd/binding/vst3/prototype.cpp.in
+++ b/include/avnd/binding/vst3/prototype.cpp.in
@@ -5,7 +5,7 @@
 #include <avnd/common/export.hpp>
 
 // clang-format off
-#include <@AVND_MAIN_FILE@>
+@AVND_MAIN_IMPORT@
 
 // Needed everywhere
 bool InitModule() { return true; }
diff --git a/include/avnd/binding/wasm/prototype.cpp.in b/include/avnd/binding/wasm/prototype.cpp.in
index ce6d31c0..14cce656 100644
--- a/include/avnd/binding/wasm/prototype.cpp.in
+++ b/include/avnd/binding/wasm/prototype.cpp.in
@@ -1,10 +1,11 @@
 /* SPDX-License-Identifier: GPL-3.0-or-later */
 
 // clang-format off
-#include <@AVND_MAIN_FILE@>
 #include <avnd/binding/wasm/configure.hpp>
 #include <avnd/binding/wasm/module.hpp>
 
+@AVND_MAIN_IMPORT@
+
 using type = decltype(avnd::configure<wasm::config, @AVND_MAIN_CLASS@>())::type;
 // clang-format on
 
diff --git a/include/halp/halp.cppm b/include/halp/halp.cppm
new file mode 100644
index 00000000..b0a6fa2d
--- /dev/null
+++ b/include/halp/halp.cppm
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-3.0-or-later OR BSL-1.0 OR CC0-1.0 OR CC-PDCC OR 0BSD
+
+// The `halp` C++20 module: exports the halp convenience layer so user objects can
+// `import halp;` instead of including the (heavy) halp headers. Only halp's own
+// dependencies are pulled in -- no binding / score / ossia / Qt -- so this builds
+// standalone. Built into the `avnd_halp_module` target (CMAKE_CXX_SCAN_FOR_MODULES).
+//
+// The global module fragment includes everything halp transitively needs so those
+// declarations stay attached to the global module; the purview then includes the
+// halp headers with HALP_MODULE_BUILD set, which turns their HALP_MODULE_EXPORT
+// markers into real `export`s.
+
+module;
+
+// --- std ---
+#include <algorithm>
+#include <array>
+#include <atomic>
+#include <cassert>
+#include <cctype>
+#include <chrono>
+#include <cmath>
+#include <complex>
+#include <concepts>
+#include <coroutine>
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <deque>
+#include <functional>
+#include <initializer_list>
+#include <iosfwd>
+#include <iostream>
+#include <iterator>
+#include <limits>
+#include <map>
+#include <memory>
+#include <mutex>
+#include <numbers>
+#include <numeric>
+#include <optional>
+#include <ostream>
+#include <ratio>
+#include <set>
+#include <span>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+#include <string_view>
+#include <thread>
+#include <tuple>
+#include <type_traits>
+#include <unordered_map>
+#include <utility>
+#include <variant>
+#include <vector>
+#include <version>
+
+// --- halp's third-party + avnd dependencies (top-level roots; each pulls its tree) ---
+#include <avnd/common/enum_reflection.hpp>
+#include <avnd/common/message_tag.hpp>
+#include <avnd/common/metadata_tag.hpp>
+#include <avnd/common/span_polyfill.hpp>
+#include <avnd/introspection/input.hpp>
+#include <boost/container/flat_map.hpp>
+#include <boost/container/small_vector.hpp>
+#include <boost/predef.h>
+#include <fmt/format.h>
+#include <fmt/printf.h>
+#include <fmt/ranges.h>
+
+export module halp;
+
+#define HALP_MODULE_BUILD 1
+
+// --- the exported halp API ---
+// Note: halp/gradient_port.hpp is intentionally omitted -- it instantiates a
+// boost::container::flat_map in an exported context, which exposes a TU-local
+// entity (ill-formed in a module interface). Gradient ports remain header-only.
+#include <halp/attributes.hpp>
+#include <halp/audio.hpp>
+#include <halp/callback.hpp>
+#include <halp/controls.hpp>
+#include <halp/controls_fmt.hpp>
+#include <halp/curve.hpp>
+#include <halp/custom_widgets.hpp>
+#include <halp/device.hpp>
+#include <halp/dynamic_port.hpp>
+#include <halp/fft.hpp>
+#include <halp/file_port.hpp>
+#include <halp/geometry.hpp>
+#include <halp/inline.hpp>
+#include <halp/layout.hpp>
+#include <halp/log.hpp>
+#include <halp/mappers.hpp>
+#include <halp/messages.hpp>
+#include <halp/meta.hpp>
+#include <halp/midi.hpp>
+#include <halp/midifile_port.hpp>
+#include <halp/modules.hpp>
+#include <halp/polyfill.hpp>
+#include <halp/reactive_value.hpp>
+#include <halp/sample_accurate_controls.hpp>
+#include <halp/schedule.hpp>
+#include <halp/shared_instance.hpp>
+#include <halp/smooth_controls.hpp>
+#include <halp/smoothers.hpp>
+#include <halp/soundfile_port.hpp>
+#include <halp/static_string.hpp>
+#include <halp/texture.hpp>
+#include <halp/texture_formats.hpp>
+#include <halp/value_types.hpp>
+
+#include <halp/controls.basic.hpp>
+#include <halp/controls.buttons.hpp>
+#include <halp/controls.enums.hpp>
+#include <halp/controls.sliders.hpp>
+#include <halp/controls.typedefs.hpp>