diff --git a/sixtyfps_runtime/corelib/callbacks.rs b/sixtyfps_runtime/corelib/callbacks.rs
index 9f2d396aa..2a8123fcd 100644
--- a/sixtyfps_runtime/corelib/callbacks.rs
+++ b/sixtyfps_runtime/corelib/callbacks.rs
@@ -69,6 +69,7 @@ fn callback_simple_test() {
     assert_eq!(c.pressed.get(), true);
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 pub(crate) mod ffi {
     #![allow(unsafe_code)]
 
diff --git a/sixtyfps_runtime/corelib/component.rs b/sixtyfps_runtime/corelib/component.rs
index 4f5b5daa0..a8e4060e1 100644
--- a/sixtyfps_runtime/corelib/component.rs
+++ b/sixtyfps_runtime/corelib/component.rs
@@ -82,6 +82,7 @@ pub fn init_component_items<Base>(
     })
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 pub(crate) mod ffi {
     #![allow(unsafe_code)]
 
diff --git a/sixtyfps_runtime/corelib/graphics.rs b/sixtyfps_runtime/corelib/graphics.rs
index d3e04dc98..6dfc54434 100644
--- a/sixtyfps_runtime/corelib/graphics.rs
+++ b/sixtyfps_runtime/corelib/graphics.rs
@@ -127,6 +127,7 @@ pub trait FontMetrics {
     fn height(&self) -> f32;
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 pub(crate) mod ffi {
     #![allow(unsafe_code)]
 
diff --git a/sixtyfps_runtime/corelib/graphics/color.rs b/sixtyfps_runtime/corelib/graphics/color.rs
index 1d09b0ec8..6779748d2 100644
--- a/sixtyfps_runtime/corelib/graphics/color.rs
+++ b/sixtyfps_runtime/corelib/graphics/color.rs
@@ -317,6 +317,7 @@ fn test_brighter_darker() {
     assert_eq!(blue.darker(0.5), Color::from_rgb_u8(0, 0, 85));
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 pub(crate) mod ffi {
     #![allow(unsafe_code)]
     use super::*;
diff --git a/sixtyfps_runtime/corelib/graphics/path.rs b/sixtyfps_runtime/corelib/graphics/path.rs
index b4cd85519..78b2c2fb3 100644
--- a/sixtyfps_runtime/corelib/graphics/path.rs
+++ b/sixtyfps_runtime/corelib/graphics/path.rs
@@ -400,6 +400,7 @@ impl PathData {
     }
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 pub(crate) mod ffi {
     #![allow(unsafe_code)]
 
diff --git a/sixtyfps_runtime/corelib/item_tree.rs b/sixtyfps_runtime/corelib/item_tree.rs
index fab330c62..a2fe46433 100644
--- a/sixtyfps_runtime/corelib/item_tree.rs
+++ b/sixtyfps_runtime/corelib/item_tree.rs
@@ -278,6 +278,7 @@ pub fn visit_item_tree<Base>(
     }
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 pub(crate) mod ffi {
     #![allow(unsafe_code)]
 
diff --git a/sixtyfps_runtime/corelib/layout.rs b/sixtyfps_runtime/corelib/layout.rs
index dacd2a6e2..ce2e61693 100644
--- a/sixtyfps_runtime/corelib/layout.rs
+++ b/sixtyfps_runtime/corelib/layout.rs
@@ -778,6 +778,7 @@ pub fn solve_path_layout(data: &PathLayoutData) {
     }
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 pub(crate) mod ffi {
     #![allow(unsafe_code)]
 
diff --git a/sixtyfps_runtime/corelib/lib.rs b/sixtyfps_runtime/corelib/lib.rs
index 15b824835..fb2fa8d08 100644
--- a/sixtyfps_runtime/corelib/lib.rs
+++ b/sixtyfps_runtime/corelib/lib.rs
@@ -74,6 +74,7 @@ pub use graphics::PathData;
 /// This only use functions from modules which are not otherwise used.
 #[doc(hidden)]
 #[cold]
+#[cfg(not(target_arch = "wasm32"))]
 pub fn use_modules() -> usize {
     tests::sixtyfps_mock_elapsed_time as usize
         + callbacks::ffi::sixtyfps_callback_init as usize
diff --git a/sixtyfps_runtime/corelib/properties.rs b/sixtyfps_runtime/corelib/properties.rs
index 417806765..524504598 100644
--- a/sixtyfps_runtime/corelib/properties.rs
+++ b/sixtyfps_runtime/corelib/properties.rs
@@ -97,7 +97,6 @@ use core::cell::{Cell, RefCell, UnsafeCell};
 use core::{marker::PhantomPinned, pin::Pin};
 use std::rc::Rc;
 
-use crate::graphics::{Brush, Color};
 use crate::items::PropertyAnimation;
 
 /// The return value of a binding
@@ -1352,8 +1351,10 @@ fn test_property_listener_scope() {
     assert!(ok);
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 pub(crate) mod ffi {
     use super::*;
+    use crate::graphics::{Brush, Color};
     use core::pin::Pin;
 
     #[allow(non_camel_case_types)]
diff --git a/sixtyfps_runtime/corelib/sharedvector.rs b/sixtyfps_runtime/corelib/sharedvector.rs
index 553754bed..afc5b5f2e 100644
--- a/sixtyfps_runtime/corelib/sharedvector.rs
+++ b/sixtyfps_runtime/corelib/sharedvector.rs
@@ -459,6 +459,7 @@ fn invalid_capacity_test() {
     let _: SharedVector<u8> = SharedVector::with_capacity(usize::MAX / 2 - 1000);
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 pub(crate) mod ffi {
     use super::*;
 
diff --git a/sixtyfps_runtime/corelib/string.rs b/sixtyfps_runtime/corelib/string.rs
index e83d073b4..23db04b9e 100644
--- a/sixtyfps_runtime/corelib/string.rs
+++ b/sixtyfps_runtime/corelib/string.rs
@@ -316,6 +316,7 @@ fn simple_test() {
     );
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 pub(crate) mod ffi {
     use super::*;
 
diff --git a/sixtyfps_runtime/corelib/timers.rs b/sixtyfps_runtime/corelib/timers.rs
index 93f6ef70a..3096c994f 100644
--- a/sixtyfps_runtime/corelib/timers.rs
+++ b/sixtyfps_runtime/corelib/timers.rs
@@ -303,6 +303,7 @@ fn lower_bound<T>(vec: &Vec<T>, mut less_than: impl FnMut(&T) -> bool) -> usize
     left
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 pub(crate) mod ffi {
     #![allow(unsafe_code)]
 
diff --git a/sixtyfps_runtime/corelib/window.rs b/sixtyfps_runtime/corelib/window.rs
index c5c6fea24..a4da8fc74 100644
--- a/sixtyfps_runtime/corelib/window.rs
+++ b/sixtyfps_runtime/corelib/window.rs
@@ -271,6 +271,7 @@ impl ComponentWindow {
     }
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 /// This module contains the functions needed to interface with the event loop and window traits
 /// from outside the Rust language.
 pub mod ffi {
diff --git a/sixtyfps_runtime/rendering_backends/default/lib.rs b/sixtyfps_runtime/rendering_backends/default/lib.rs
index ac9cce1a9..594d85698 100644
--- a/sixtyfps_runtime/rendering_backends/default/lib.rs
+++ b/sixtyfps_runtime/rendering_backends/default/lib.rs
@@ -69,6 +69,7 @@ pub use default_backend::{
 
 #[doc(hidden)]
 #[cold]
+#[cfg(not(target_arch = "wasm32"))]
 pub fn use_modules() {
     default_backend::use_modules();
     #[cfg(feature = "sixtyfps-rendering-backend-qt")]
@@ -77,6 +78,7 @@ pub fn use_modules() {
     sixtyfps_rendering_backend_gl::use_modules();
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 pub mod ffi {
     use sixtyfps_corelib::window::ffi::ComponentWindowOpaque;
     use sixtyfps_corelib::window::ComponentWindow;
diff --git a/sixtyfps_runtime/rendering_backends/gl/lib.rs b/sixtyfps_runtime/rendering_backends/gl/lib.rs
index bea372f2c..9bc9d01e1 100644
--- a/sixtyfps_runtime/rendering_backends/gl/lib.rs
+++ b/sixtyfps_runtime/rendering_backends/gl/lib.rs
@@ -1399,6 +1399,7 @@ pub fn create_gl_window_with_canvas_id(canvas_id: String) -> ComponentWindow {
 
 #[doc(hidden)]
 #[cold]
+#[cfg(not(target_arch = "wasm32"))]
 pub fn use_modules() {
     sixtyfps_corelib::use_modules();
 }
diff --git a/sixtyfps_runtime/rendering_backends/qt/lib.rs b/sixtyfps_runtime/rendering_backends/qt/lib.rs
index d7887f6d1..3783e4d65 100644
--- a/sixtyfps_runtime/rendering_backends/qt/lib.rs
+++ b/sixtyfps_runtime/rendering_backends/qt/lib.rs
@@ -31,6 +31,7 @@ mod key_generated;
 
 #[doc(hidden)]
 #[cold]
+#[cfg(not(target_arch = "wasm32"))]
 pub fn use_modules() -> usize {
     sixtyfps_corelib::use_modules() + {
         #[cfg(no_qt)]