diff --git a/crates/wasm_interp/src/lib.rs b/crates/wasm_interp/src/lib.rs
index 1417751561..f134b54857 100644
--- a/crates/wasm_interp/src/lib.rs
+++ b/crates/wasm_interp/src/lib.rs
@@ -2,9 +2,25 @@ mod call_stack;
 mod instance;
 pub mod test_utils;
 mod value_stack;
-mod wasi;
+pub mod wasi;
+
+// Main external interface
+pub use instance::Instance;
 
 // Exposed for testing only. Should eventually become private.
 pub use call_stack::CallStack;
-pub use instance::{Action, Instance};
+pub use instance::Action;
 pub use value_stack::ValueStack;
+
+use roc_wasm_module::Value;
+
+pub trait ImportDispatcher {
+    /// Dispatch a call from WebAssembly to your own code, based on module and function name.
+    fn dispatch(
+        &mut self,
+        module_name: &str,
+        function_name: &str,
+        arguments: &[Value],
+        memory: &mut [u8],
+    ) -> Option<Value>;
+}
diff --git a/crates/wasm_interp/src/wasi.rs b/crates/wasm_interp/src/wasi.rs
index d768561bee..a1f8e573e9 100644
--- a/crates/wasm_interp/src/wasi.rs
+++ b/crates/wasm_interp/src/wasi.rs
@@ -1,88 +1,54 @@
 use roc_wasm_module::Value;
 
-pub trait ImportDispatcher {
-    /// Dispatch a call from WebAssembly to your own code, based on module and function name.
-    /// The call arguments are passed in, along with a mutable pointer to WebAssembly memory.
-    fn dispatch(
-        &mut self,
-        module_name: &str,
-        function_name: &str,
-        arguments: &[Value],
-        memory: &mut [u8],
-    ) -> Option<Value>;
-}
+pub const MODULE_NAME: &'static str = "wasi_snapshot_preview1";
 
-pub trait ImportDispatcherModule {
-    const NAME: &'static str;
-
-    /// Dispatch a call from WebAssembly to your own code, based on the function name.
-    /// The call arguments are passed in, along with a mutable pointer to WebAssembly memory.
-    fn dispatch(
-        &mut self,
-        function_name: &str,
-        arguments: &[Value],
-        memory: &mut [u8],
-    ) -> Option<Value>;
-}
-
-pub struct WasiDispatcher {}
-
-impl ImportDispatcherModule for WasiDispatcher {
-    const NAME: &'static str = "wasi_snapshot_preview1";
-
-    fn dispatch(
-        &mut self,
-        function_name: &str,
-        arguments: &[Value],
-        _memory: &mut [u8],
-    ) -> Option<Value> {
-        match function_name {
-            "args_get" => todo!("WASI {}({:?})", function_name, arguments),
-            "args_sizes_get" => todo!("WASI {}({:?})", function_name, arguments),
-            "environ_get" => todo!("WASI {}({:?})", function_name, arguments),
-            "environ_sizes_get" => todo!("WASI {}({:?})", function_name, arguments),
-            "clock_res_get" => todo!("WASI {}({:?})", function_name, arguments),
-            "clock_time_get" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_advise" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_allocate" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_close" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_datasync" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_fdstat_get" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_fdstat_set_flags" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_fdstat_set_rights" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_filestat_get" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_filestat_set_size" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_filestat_set_times" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_pread" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_prestat_get" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_prestat_dir_name" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_pwrite" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_read" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_readdir" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_renumber" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_seek" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_sync" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_tell" => todo!("WASI {}({:?})", function_name, arguments),
-            "fd_write" => todo!("WASI {}({:?})", function_name, arguments),
-            "path_create_directory" => todo!("WASI {}({:?})", function_name, arguments),
-            "path_filestat_get" => todo!("WASI {}({:?})", function_name, arguments),
-            "path_filestat_set_times" => todo!("WASI {}({:?})", function_name, arguments),
-            "path_link" => todo!("WASI {}({:?})", function_name, arguments),
-            "path_open" => todo!("WASI {}({:?})", function_name, arguments),
-            "path_readlink" => todo!("WASI {}({:?})", function_name, arguments),
-            "path_remove_directory" => todo!("WASI {}({:?})", function_name, arguments),
-            "path_rename" => todo!("WASI {}({:?})", function_name, arguments),
-            "path_symlink" => todo!("WASI {}({:?})", function_name, arguments),
-            "path_unlink_file" => todo!("WASI {}({:?})", function_name, arguments),
-            "poll_oneoff" => todo!("WASI {}({:?})", function_name, arguments),
-            "proc_exit" => todo!("WASI {}({:?})", function_name, arguments),
-            "proc_raise" => todo!("WASI {}({:?})", function_name, arguments),
-            "sched_yield" => todo!("WASI {}({:?})", function_name, arguments),
-            "random_get" => todo!("WASI {}({:?})", function_name, arguments),
-            "sock_recv" => todo!("WASI {}({:?})", function_name, arguments),
-            "sock_send" => todo!("WASI {}({:?})", function_name, arguments),
-            "sock_shutdown" => todo!("WASI {}({:?})", function_name, arguments),
-            _ => panic!("Unknown WASI function {}({:?})", function_name, arguments),
-        }
+pub fn dispatch(function_name: &str, arguments: &[Value], _memory: &mut [u8]) -> Option<Value> {
+    match function_name {
+        "args_get" => todo!("WASI {}({:?})", function_name, arguments),
+        "args_sizes_get" => todo!("WASI {}({:?})", function_name, arguments),
+        "environ_get" => todo!("WASI {}({:?})", function_name, arguments),
+        "environ_sizes_get" => todo!("WASI {}({:?})", function_name, arguments),
+        "clock_res_get" => todo!("WASI {}({:?})", function_name, arguments),
+        "clock_time_get" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_advise" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_allocate" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_close" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_datasync" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_fdstat_get" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_fdstat_set_flags" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_fdstat_set_rights" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_filestat_get" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_filestat_set_size" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_filestat_set_times" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_pread" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_prestat_get" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_prestat_dir_name" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_pwrite" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_read" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_readdir" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_renumber" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_seek" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_sync" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_tell" => todo!("WASI {}({:?})", function_name, arguments),
+        "fd_write" => todo!("WASI {}({:?})", function_name, arguments),
+        "path_create_directory" => todo!("WASI {}({:?})", function_name, arguments),
+        "path_filestat_get" => todo!("WASI {}({:?})", function_name, arguments),
+        "path_filestat_set_times" => todo!("WASI {}({:?})", function_name, arguments),
+        "path_link" => todo!("WASI {}({:?})", function_name, arguments),
+        "path_open" => todo!("WASI {}({:?})", function_name, arguments),
+        "path_readlink" => todo!("WASI {}({:?})", function_name, arguments),
+        "path_remove_directory" => todo!("WASI {}({:?})", function_name, arguments),
+        "path_rename" => todo!("WASI {}({:?})", function_name, arguments),
+        "path_symlink" => todo!("WASI {}({:?})", function_name, arguments),
+        "path_unlink_file" => todo!("WASI {}({:?})", function_name, arguments),
+        "poll_oneoff" => todo!("WASI {}({:?})", function_name, arguments),
+        "proc_exit" => todo!("WASI {}({:?})", function_name, arguments),
+        "proc_raise" => todo!("WASI {}({:?})", function_name, arguments),
+        "sched_yield" => todo!("WASI {}({:?})", function_name, arguments),
+        "random_get" => todo!("WASI {}({:?})", function_name, arguments),
+        "sock_recv" => todo!("WASI {}({:?})", function_name, arguments),
+        "sock_send" => todo!("WASI {}({:?})", function_name, arguments),
+        "sock_shutdown" => todo!("WASI {}({:?})", function_name, arguments),
+        _ => panic!("Unknown WASI function {}({:?})", function_name, arguments),
     }
 }