diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index 5cd0b05f0d..d67dc4dd7d 100644
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -119,10 +119,6 @@ if(MINIMAL_BUILD)
     set(USD_SUPPORT OFF)
 endif()
 
-if(NOT BUILD_SHARED_LIBS)
-    message(FATAL_ERROR "BUILD_SHARED_LIBS=OFF is not supported. Configure with -DBUILD_SHARED_LIBS=ON.")
-endif()
-
 if((BUILD_CONVERT OR BUILD_GEOMSERVER OR BUILD_IFCPYTHON) AND(NOT BUILD_IFCGEOM))
     message(STATUS "'IfcGeom' is required with current outputs")
     set(BUILD_IFCGEOM ON)
diff --git a/nix/build-all.py b/nix/build-all.py
index 2fa2626e6e..79b0a64932 100644
--- a/nix/build-all.py
+++ b/nix/build-all.py
@@ -591,6 +591,10 @@ def run_cmake(arg1, cmake_args: "list[str]", cmake_dir: Union[str, None] = None,
             f"-DBUILD_SHARED_LIBS={OFF_ON[not BUILD_STATIC]}",
         )
 
+    module_flags = []
+    if "wasm" in flags:
+        module_flags.append(f"-DCMAKE_MODULE_LINKER_FLAGS={os.environ['LDFLAGS']}")
+
     run(
         [
             *wasm,
@@ -600,6 +604,7 @@ def run_cmake(arg1, cmake_args: "list[str]", cmake_dir: Union[str, None] = None,
             *cmake_args,
             f"-DCMAKE_BUILD_TYPE={BUILD_CFG}",
             f"-DCMAKE_SHARED_LINKER_FLAGS={os.environ['LDFLAGS']}",
+            *module_flags
         ],
         cwd=cwd,
     )
@@ -1341,7 +1346,7 @@ os.makedirs(ifcos_build_dir, exist_ok=True)
 cmake_args = [
     "-DUSE_MMAP=OFF",
     "-DBUILD_EXAMPLES=OFF",
-    "-DBUILD_SHARED_LIBS=ON",
+    "-DBUILD_SHARED_LIBS=" + OFF_ON[not BUILD_STATIC],
     "-DGLTF_SUPPORT=ON",
     "-DBoost_NO_BOOST_CMAKE=On",
     "-DCREATE_BUNDLE=On",
@@ -1394,9 +1399,9 @@ elif "occ" in targets:
     occ_library_dir = f"{DEPS_DIR}/install/oce-{OCE_VERSION}/lib"
     cmake_args.extend(["-DOCC_INCLUDE_DIR=" + occ_include_dir, "-DOCC_LIBRARY_DIR=" + occ_library_dir])
 
-if "manifold" in targets:
-    cmake_args_prefix_path.append(f"{DEPS_DIR}/install/manifold-{MANIFOLD_VERSION}")
-    cmake_args.append("-DWITH_MANIFOLD=On")
+# if "manifold" in targets:
+#     cmake_args_prefix_path.append(f"{DEPS_DIR}/install/manifold-{MANIFOLD_VERSION}")
+#     cmake_args.append("-DWITH_MANIFOLD=On")
 
 if "OpenCOLLADA" in targets:
     # pcre is a dependency of OpenCOLLADA, but since we `find_package`,
diff --git a/pyodide/meta.yaml b/pyodide/meta.yaml
index 7c6580d801..fd8e6b4102 100644
--- a/pyodide/meta.yaml
+++ b/pyodide/meta.yaml
@@ -8,7 +8,7 @@ source:
 
 build:
   script: |
-    BUILD_CFG=Release python nix/build-all.py -v --wasm --py313
+    CFLAGS="-O0 -g" CXXFLAGS="-O0 -g" LDFLAGS="-O0 -g" IFCOS_SCHEMAS=4 BUILD_CFG=Debug python nix/build-all.py -v --wasm --py313
 
 about:
   home: http://ifcopenshell.org
diff --git a/src/ifcgeom/Serialization/schema/CMakeLists.txt b/src/ifcgeom/Serialization/schema/CMakeLists.txt
index 5d56ebf383..c9e77debe6 100644
--- a/src/ifcgeom/Serialization/schema/CMakeLists.txt
+++ b/src/ifcgeom/Serialization/schema/CMakeLists.txt
@@ -1,3 +1,5 @@
+if (NOT WASM_BUILD)
+
 foreach(schema ${SCHEMA_VERSIONS})
     add_library(geometry_serializer_ifc${schema} SHARED Serialization.cpp plugin.cpp)
     target_link_libraries(geometry_serializer_ifc${schema} PRIVATE plugin geometry_serializer IfcGeom IfcParse ${OpenCASCADE_LIBRARIES})
@@ -10,3 +12,5 @@ foreach(schema ${SCHEMA_VERSIONS})
     list(APPEND geometry_serializer_libraries geometry_serializer_ifc${schema})
 endforeach()
 set(geometry_serializer_libraries ${geometry_serializer_libraries} PARENT_SCOPE)
+
+endif()
diff --git a/src/ifcgeom/kernels/CMakeLists.txt b/src/ifcgeom/kernels/CMakeLists.txt
index af5b415ef9..7794bd05f7 100644
--- a/src/ifcgeom/kernels/CMakeLists.txt
+++ b/src/ifcgeom/kernels/CMakeLists.txt
@@ -2,6 +2,12 @@ message(STATUS "GEOMETRY_KERNELS ${GEOMETRY_KERNELS}")
 
 set(kernel_plugin_runtime_dir "${CMAKE_BINARY_DIR}/ifcgeom/$<CONFIG>")
 
+if (NOT WASM_BUILD)
+# wasm-ld (?) trips up on multiple defined symbols. IfcParse already brings
+# in plugin so we skip it here.
+set(plugin_when_not_wasm plugin)
+endif()
+
 foreach(kernel ${GEOMETRY_KERNELS})
     string(TOUPPER ${kernel} KERNEL_UPPER)
     file(GLOB IFCGEOM_H_FILES ${kernel}/*.h)
@@ -16,6 +22,14 @@ foreach(kernel ${GEOMETRY_KERNELS})
 
     set(KERNEL_TARGET "geometry_kernel_${kernel}")
     add_library(${KERNEL_TARGET} SHARED ${IFCGEOM_FILES})
+
+    if (WASM_BUILD)
+        target_link_options(
+            ${KERNEL_TARGET}
+            PRIVATE "SHELL:-s -s SIDE_MODULE=1"
+        )
+    endif()    
+
     set_target_properties(${KERNEL_TARGET} PROPERTIES
         COMPILE_FLAGS "-DIFC_GEOMLIBRARY_EXPORTS"
         OUTPUT_NAME "geometry.kernel.${kernel}"
@@ -23,7 +37,7 @@ foreach(kernel ${GEOMETRY_KERNELS})
         LIBRARY_OUTPUT_DIRECTORY "${kernel_plugin_runtime_dir}"
     )
     list(APPEND kernel_libraries ${KERNEL_TARGET})
-    target_link_libraries(${KERNEL_TARGET} PRIVATE plugin IfcGeom ${${KERNEL_UPPER}_LIBRARIES} Eigen3::Eigen)
+    target_link_libraries(${KERNEL_TARGET} PRIVATE ${plugin_when_not_wasm} IfcGeom ${${KERNEL_UPPER}_LIBRARIES} Eigen3::Eigen)
 
     install(TARGETS ${KERNEL_TARGET})
 
@@ -32,6 +46,14 @@ foreach(kernel ${GEOMETRY_KERNELS})
 
         set(KERNEL_TARGET_SIMPLE "${KERNEL_TARGET}_simple")
         add_library(${KERNEL_TARGET_SIMPLE} SHARED ${IFCGEOM_FILES})
+
+    if (WASM_BUILD)
+        target_link_options(
+            ${KERNEL_TARGET_SIMPLE}
+            PRIVATE "SHELL:-s -s SIDE_MODULE=1"
+        )
+    endif()
+
         set_target_properties(${KERNEL_TARGET_SIMPLE} PROPERTIES
             COMPILE_FLAGS "-DIFC_GEOMLIBRARY_EXPORTS -DIFOPSH_SIMPLE_KERNEL -DCGAL_HAS_THREADS"
             OUTPUT_NAME "geometry.kernel.cgalsimple"
@@ -39,11 +61,20 @@ foreach(kernel ${GEOMETRY_KERNELS})
             LIBRARY_OUTPUT_DIRECTORY "${kernel_plugin_runtime_dir}"
         )
         list(APPEND kernel_libraries ${KERNEL_TARGET_SIMPLE})
-        target_link_libraries(${KERNEL_TARGET_SIMPLE} PRIVATE plugin IfcGeom ${${KERNEL_UPPER}_LIBRARIES} Eigen3::Eigen)
+        target_link_libraries(${KERNEL_TARGET_SIMPLE} PRIVATE ${plugin_when_not_wasm} IfcGeom ${${KERNEL_UPPER}_LIBRARIES} Eigen3::Eigen)
         install(TARGETS ${KERNEL_TARGET_SIMPLE})
     elseif(${kernel} STREQUAL "opencascade")
-        target_link_libraries(${KERNEL_TARGET} PRIVATE ${OpenCASCADE_LIBRARIES})
+        if (WASM_BUILD)
+            # exclude due to duplicate symbols tripping up wasm-ld
+            set(OCCT_LIBS_FILTERED ${OpenCASCADE_LIBRARIES})
+            list(FILTER OCCT_LIBS_FILTERED EXCLUDE REGEX "(^|;)TKXMesh($|;)")
+            target_link_libraries(${KERNEL_TARGET} PRIVATE ${OCCT_LIBS_FILTERED})
+		# message(FATAL_ERROR "OCCT_LIBS_FILTERED ${OCCT_LIBS_FILTERED}")
+        else()
+            target_link_libraries(${KERNEL_TARGET} PRIVATE ${OpenCASCADE_LIBRARIES})
+        endif()
 
+	if (NOT WASM_BUILD)
         foreach(tree_backend brep trianglebvh)
             set(TREE_TARGET "geometry_tree_opencascade_${tree_backend}")
             add_library(${TREE_TARGET} SHARED
@@ -60,6 +91,7 @@ foreach(kernel ${GEOMETRY_KERNELS})
             target_link_libraries(${TREE_TARGET} PRIVATE plugin IfcGeom geometry_kernel_opencascade ${OpenCASCADE_LIBRARIES} Eigen3::Eigen)
             install(TARGETS ${TREE_TARGET})
         endforeach()
+	endif()
     endif()
 
     install(FILES ${IFCGEOM_H_FILES}
diff --git a/src/ifcgeom/mapping/CMakeLists.txt b/src/ifcgeom/mapping/CMakeLists.txt
index 77778df425..b218453248 100644
--- a/src/ifcgeom/mapping/CMakeLists.txt
+++ b/src/ifcgeom/mapping/CMakeLists.txt
@@ -2,6 +2,12 @@ find_package(Eigen3 REQUIRED)
 
 set(mapping_plugin_runtime_dir "${CMAKE_BINARY_DIR}/ifcgeom/$<CONFIG>")
 
+if (NOT WASM_BUILD)
+# wasm-ld (?) trips up on multiple defined symbols. IfcParse already brings
+# in plugin so we skip it here.
+set(plugin_when_not_wasm plugin)
+endif()
+
 foreach(schema ${SCHEMA_VERSIONS})
     file(GLOB IFCGEOM_I_FILES *.i)
     file(GLOB IFCGEOM_H_FILES *.h)
@@ -15,7 +21,15 @@ foreach(schema ${SCHEMA_VERSIONS})
         RUNTIME_OUTPUT_DIRECTORY "${mapping_plugin_runtime_dir}"
         LIBRARY_OUTPUT_DIRECTORY "${mapping_plugin_runtime_dir}"
     )
-    target_link_libraries(geometry_mapping_ifc${schema} PRIVATE plugin IfcGeom IfcParse Eigen3::Eigen ${OpenCASCADE_LIBRARIES})
+
+    if (WASM_BUILD)
+        target_link_options(
+            geometry_mapping_ifc${schema}
+            PRIVATE "SHELL:-s -s SIDE_MODULE=1"
+        )
+    endif()
+
+    target_link_libraries(geometry_mapping_ifc${schema} PRIVATE ${plugin_when_not_wasm} IfcGeom IfcParse Eigen3::Eigen)
 
     list(APPEND mapping_libraries geometry_mapping_ifc${schema})
 
diff --git a/src/ifcparse/character_decoder.cpp b/src/ifcparse/character_decoder.cpp
index b354c70052..89b96156cc 100644
--- a/src/ifcparse/character_decoder.cpp
+++ b/src/ifcparse/character_decoder.cpp
@@ -311,11 +311,11 @@ std::string character_decoder<Reader>::get(size_t& ptr) {
     return s;
 }
 
-template class IFC_PARSE_API character_decoder<file_reader<full_buffer_impl>>;
-template class IFC_PARSE_API character_decoder<file_reader<paged_file_impl>>;
-template class IFC_PARSE_API character_decoder<file_reader<pushed_sequential_impl>>;
+template class IFC_PARSE_API ifcopenshell::character_decoder<file_reader<full_buffer_impl>>;
+template class IFC_PARSE_API ifcopenshell::character_decoder<file_reader<paged_file_impl>>;
+template class IFC_PARSE_API ifcopenshell::character_decoder<file_reader<pushed_sequential_impl>>;
 #ifdef USE_MMAP
-template class IFC_PARSE_API character_decoder<file_reader<mmap_impl>>;
+template class IFC_PARSE_API ifcopenshell::character_decoder<file_reader<mmap_impl>>;
 #endif
 
 character_encoder::character_encoder(const std::string& input)
diff --git a/src/ifcparse/file.h b/src/ifcparse/file.h
index f0f74583ad..f4a900b5f8 100644
--- a/src/ifcparse/file.h
+++ b/src/ifcparse/file.h
@@ -412,16 +412,6 @@ public:
 
     void build_inverses_(const express::Base& entity);
 
-    // @nb this does not support id assignment
-    template <typename T, typename... Ts>
-    T create(Ts&&... args) {
-        T t = create(&T::Class()).template as<T>();
-        if constexpr (sizeof...(Ts) > 0) {
-            t.initialize(std::forward<Ts>(args)...);
-        }
-        return t;
-    }
-
     template <typename T>
     T create(int instance_id = -1) {
         return create(&T::Class(), instance_id).template as<T>();
diff --git a/src/ifcparse/parse.cpp b/src/ifcparse/parse.cpp
index f1a1ba2fd6..14ebb1a1b4 100644
--- a/src/ifcparse/parse.cpp
+++ b/src/ifcparse/parse.cpp
@@ -411,11 +411,11 @@ token spf_lexer<Reader>::next() {
     }
 }
 
-template class IFC_PARSE_API spf_lexer<file_reader<full_buffer_impl>>;
-template class IFC_PARSE_API spf_lexer<file_reader<paged_file_impl>>;
-template class IFC_PARSE_API spf_lexer<file_reader<pushed_sequential_impl>>;
+template class IFC_PARSE_API ifcopenshell::spf_lexer<file_reader<full_buffer_impl>>;
+template class IFC_PARSE_API ifcopenshell::spf_lexer<file_reader<paged_file_impl>>;
+template class IFC_PARSE_API ifcopenshell::spf_lexer<file_reader<pushed_sequential_impl>>;
 #ifdef USE_MMAP
-template class IFC_PARSE_API spf_lexer<file_reader<mmap_impl>>;
+template class IFC_PARSE_API ifcopenshell::spf_lexer<file_reader<mmap_impl>>;
 #endif
 
 bool token::is_operator() {
diff --git a/src/serializers/CMakeLists.txt b/src/serializers/CMakeLists.txt
index 7e86046a9c..093a931094 100644
--- a/src/serializers/CMakeLists.txt
+++ b/src/serializers/CMakeLists.txt
@@ -4,12 +4,18 @@ set(geometry_serializer_plugin_runtime_dir "${CMAKE_BINARY_DIR}/serializers/$<CO
 file(GLOB SERIALIZERS_H_FILES *.h)
 file(GLOB SERIALIZERS_S_H_FILES schema_dependent/*.h)
 
+if (NOT WASM_BUILD)
+# wasm-ld (?) trips up on multiple defined symbols. IfcParse already brings
+# in plugin so we skip it here.
+set(plugin_when_not_wasm plugin)
+endif()
+
 function(add_document_serializer_plugin target output_name)
     cmake_parse_arguments(PLUGIN "" "" "SOURCES;LIBRARIES;DEFINITIONS" ${ARGN})
 
     add_library(${target} SHARED ${PLUGIN_SOURCES})
     target_compile_definitions(${target} PRIVATE SERIALIZERS_EXPORTS BOOST_DLL_USE_STD_FS ${PLUGIN_DEFINITIONS})
-    target_link_libraries(${target} PRIVATE plugin IfcGeom IfcParse ${PLUGIN_LIBRARIES})
+    target_link_libraries(${target} PRIVATE ${plugin_when_not_wasm} IfcGeom IfcParse ${PLUGIN_LIBRARIES})
     set_target_properties(${target} PROPERTIES
         OUTPUT_NAME "${output_name}"
         RUNTIME_OUTPUT_DIRECTORY "${document_serializer_plugin_runtime_dir}"
@@ -18,6 +24,13 @@ function(add_document_serializer_plugin target output_name)
 
     list(APPEND document_serializer_libraries ${target})
     set(document_serializer_libraries ${document_serializer_libraries} PARENT_SCOPE)
+
+    if (WASM_BUILD)
+        target_link_options(
+            ${target}
+            PRIVATE "SHELL:-s -s SIDE_MODULE=1"
+        )
+    endif()
 endfunction()
 
 function(add_geometry_serializer_plugin target output_name)
@@ -25,7 +38,7 @@ function(add_geometry_serializer_plugin target output_name)
 
     add_library(${target} SHARED ${PLUGIN_SOURCES})
     target_compile_definitions(${target} PRIVATE SERIALIZERS_EXPORTS BOOST_DLL_USE_STD_FS ${PLUGIN_DEFINITIONS})
-    target_link_libraries(${target} PRIVATE plugin IfcGeom IfcParse ${PLUGIN_LIBRARIES})
+    target_link_libraries(${target} PRIVATE ${plugin_when_not_wasm} IfcGeom IfcParse ${PLUGIN_LIBRARIES})
     if(WITH_PROJ)
         find_package(proj REQUIRED)
         target_compile_definitions(${target} PRIVATE "WITH_PROJ")
@@ -42,6 +55,14 @@ function(add_geometry_serializer_plugin target output_name)
 
     list(APPEND geometry_serializer_libraries ${target})
     set(geometry_serializer_libraries ${geometry_serializer_libraries} PARENT_SCOPE)
+
+    if (WASM_BUILD)
+        target_link_options(
+            ${target}
+            PRIVATE "SHELL:-s -s SIDE_MODULE=1"
+        )
+    endif()
+
 endfunction()
 
 if(WITH_ROCKSDB)
@@ -50,13 +71,15 @@ endif()
 
 add_subdirectory(schema_dependent)
 
+if (NOT WASM_BUILD)
 set(ttl_geometry_serializer_libraries)
 if(WITH_OPENCASCADE)
     set(ttl_geometry_serializer_libraries geometry_kernel_opencascade ${OpenCASCADE_LIBRARIES})
 endif()
+add_geometry_serializer_plugin(geometry_serializer_ttl "geometry.ttl" SOURCES geometry_ttl_plugin.cpp TtlWktSerializer.cpp LIBRARIES ${ttl_geometry_serializer_libraries})
+endif()
 
 add_geometry_serializer_plugin(geometry_serializer_obj "geometry.obj" SOURCES geometry_obj_plugin.cpp WavefrontObjSerializer.cpp)
-add_geometry_serializer_plugin(geometry_serializer_ttl "geometry.ttl" SOURCES geometry_ttl_plugin.cpp TtlWktSerializer.cpp LIBRARIES ${ttl_geometry_serializer_libraries})
 
 if(OPENCOLLADA_FOUND)
     add_geometry_serializer_plugin(geometry_serializer_dae "geometry.dae" SOURCES geometry_dae_plugin.cpp ColladaSerializer.cpp LIBRARIES OpenCOLLADA::OpenCOLLADA DEFINITIONS WITH_OPENCOLLADA)
@@ -70,7 +93,7 @@ if(USD_SUPPORT)
     add_geometry_serializer_plugin(geometry_serializer_usd "geometry.usd" SOURCES geometry_usd_plugin.cpp USDSerializer.cpp LIBRARIES pxr::USD)
 endif()
 
-if(WITH_OPENCASCADE)
+if(WITH_OPENCASCADE AND NOT WASM_BUILD)
     set(opencascade_geometry_serializer_libraries geometry_kernel_opencascade ${OpenCASCADE_LIBRARIES})
     add_geometry_serializer_plugin(geometry_serializer_stp "geometry.stp" SOURCES geometry_stp_plugin.cpp OpenCascadeBasedSerializer.cpp LIBRARIES ${opencascade_geometry_serializer_libraries})
     add_geometry_serializer_plugin(geometry_serializer_igs "geometry.igs" SOURCES geometry_igs_plugin.cpp OpenCascadeBasedSerializer.cpp LIBRARIES ${opencascade_geometry_serializer_libraries})