diff --git a/lib/api/Cargo.toml b/lib/api/Cargo.toml
index a08f8d87f..8817ba65f 100644
--- a/lib/api/Cargo.toml
+++ b/lib/api/Cargo.toml
@@ -100,6 +100,7 @@ core = ["hashbrown"]
 sys = [
   "wasmer-compiler/translator",
   "wasmer-compiler/compiler",
+  "std",
 ]
 sys-default = ["sys", "wat", "cranelift"]
 # - Compilers.
diff --git a/lib/api/src/engine.rs b/lib/api/src/engine.rs
index 605626aa4..10adb5818 100644
--- a/lib/api/src/engine.rs
+++ b/lib/api/src/engine.rs
@@ -42,12 +42,6 @@ impl Default for Engine {
     }
 }
 
-// impl Into<Engine> for engine_imp::Engine {
-//     fn into(self) -> Engine {
-//         Engine(self)
-//     }
-// }
-
 impl From<engine_imp::Engine> for Engine {
     fn from(inner: engine_imp::Engine) -> Self {
         Self(inner)
diff --git a/lib/api/src/errors.rs b/lib/api/src/errors.rs
index c5a9ad5ec..4b65e654f 100644
--- a/lib/api/src/errors.rs
+++ b/lib/api/src/errors.rs
@@ -4,43 +4,6 @@ use thiserror::Error;
 #[cfg(feature = "sys")]
 pub use wasmer_compiler::{LinkError, RuntimeError};
 
-// /// An error while instantiating a module.
-// ///
-// /// This is not a common WebAssembly error, however
-// /// we need to differentiate from a `LinkError` (an error
-// /// that happens while linking, on instantiation), a
-// /// Trap that occurs when calling the WebAssembly module
-// /// start function, and an error when initializing the user's
-// /// host environments.
-// #[derive(Debug)]
-// #[cfg_attr(feature = "std", derive(Error))]
-// pub enum InstantiationError {
-//     /// A linking ocurred during instantiation.
-//     #[cfg_attr(feature = "std", error(transparent))]
-//     Link(LinkError),
-
-//     /// A runtime error occured while invoking the start function
-//     #[cfg_attr(feature = "std", error(transparent))]
-//     Start(RuntimeError),
-
-//     /// The module was compiled with a CPU feature that is not available on
-//     /// the current host.
-//     #[cfg_attr(feature = "std", error("missing required CPU features: {0:?}"))]
-//     CpuFeature(String),
-
-//     /// Import from a different [`Store`].
-//     /// This error occurs when an import from a different store is used.
-//     #[cfg_attr(feature = "std", error("cannot mix imports from different stores"))]
-//     DifferentStores,
-// }
-
-// #[cfg(feature = "core")]
-// impl std::fmt::Display for InstantiationError {
-//     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-//         write!(f, "InstantiationError")
-//     }
-// }
-
 /// An error while instantiating a module.
 ///
 /// This is not a common WebAssembly error, however
@@ -49,28 +12,36 @@ pub use wasmer_compiler::{LinkError, RuntimeError};
 /// Trap that occurs when calling the WebAssembly module
 /// start function, and an error when initializing the user's
 /// host environments.
-#[derive(Error, Debug)]
+#[derive(Debug)]
+#[cfg_attr(feature = "std", derive(Error))]
 pub enum InstantiationError {
     /// A linking ocurred during instantiation.
-    #[error(transparent)]
+    #[cfg_attr(feature = "std", error(transparent))]
     Link(LinkError),
 
     /// A runtime error occured while invoking the start function
-    #[error(transparent)]
+    #[cfg_attr(feature = "std", error(transparent))]
     Start(RuntimeError),
 
     /// The module was compiled with a CPU feature that is not available on
     /// the current host.
-    #[error("missing required CPU features: {0:?}")]
+    #[cfg_attr(feature = "std", error("missing required CPU features: {0:?}"))]
     CpuFeature(String),
 
-    /// Import from a different Store.
+    /// Import from a different [`Store`].
     /// This error occurs when an import from a different store is used.
-    #[error("cannot mix imports from different stores")]
+    #[cfg_attr(feature = "std", error("cannot mix imports from different stores"))]
     DifferentStores,
 
     /// Import from a different Store.
     /// This error occurs when an import from a different store is used.
-    #[error("incorrect OS or architecture")]
+    #[cfg_attr(feature = "std", error("incorrect OS or architecture"))]
     DifferentArchOS,
 }
+
+#[cfg(feature = "core")]
+impl std::fmt::Display for InstantiationError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "InstantiationError")
+    }
+}
diff --git a/lib/api/src/js/extern_ref.rs b/lib/api/src/js/extern_ref.rs
index 7fad48ea9..a2ff01016 100644
--- a/lib/api/src/js/extern_ref.rs
+++ b/lib/api/src/js/extern_ref.rs
@@ -13,25 +13,25 @@ impl ExternRef {
     where
         T: Any + Send + Sync + 'static + Sized,
     {
-        unimplemented!();
+        unimplemented!("ExternRef is not yet supported in Javascript");
     }
 
     pub fn downcast<'a, T>(&self, store: &'a impl AsStoreRef) -> Option<&'a T>
     where
         T: Any + Send + Sync + 'static + Sized,
     {
-        unimplemented!();
+        unimplemented!("ExternRef is not yet supported in Javascript");
     }
 
     pub(crate) fn vm_externref(&self) -> VMExternRef {
-        unimplemented!();
+        unimplemented!("ExternRef is not yet supported in Javascript");
     }
 
     pub(crate) unsafe fn from_vm_externref(
         store: &mut impl AsStoreMut,
         vm_externref: VMExternRef,
     ) -> Self {
-        unimplemented!();
+        unimplemented!("ExternRef is not yet supported in Javascript");
     }
 
     pub fn is_from_store(&self, store: &impl AsStoreRef) -> bool {
diff --git a/lib/api/src/js/module.rs b/lib/api/src/js/module.rs
index a45a5ead6..0a8cee64f 100644
--- a/lib/api/src/js/module.rs
+++ b/lib/api/src/js/module.rs
@@ -237,7 +237,8 @@ impl Module {
         bytes: impl IntoBytes,
     ) -> Result<Self, DeserializeError> {
         #[cfg(feature = "js-serializable-module")]
-        return Self::new(_engine, bytes.into_bytes()).map_err(|e| DeserializeError::Compiler(e));
+        return Self::from_binary(_engine, &bytes.into_bytes())
+            .map_err(|e| DeserializeError::Compiler(e));
 
         #[cfg(not(feature = "js-serializable-module"))]
         return Err(DeserializeError::Generic("You need to enable the `js-serializable-module` feature flag to deserialize a `Module`".to_string()));
diff --git a/lib/api/src/js/vm.rs b/lib/api/src/js/vm.rs
index 1e48d0d67..0ce76e489 100644
--- a/lib/api/src/js/vm.rs
+++ b/lib/api/src/js/vm.rs
@@ -110,6 +110,7 @@ impl VMMemory {
 /// The shared memory is the same as the normal memory
 pub type VMSharedMemory = VMMemory;
 
+/// The VM Global type
 #[derive(Clone, Debug, PartialEq)]
 pub struct VMGlobal {
     pub(crate) global: JsGlobal,
@@ -125,6 +126,7 @@ impl VMGlobal {
 unsafe impl Send for VMGlobal {}
 unsafe impl Sync for VMGlobal {}
 
+/// The VM Table type
 #[derive(Clone, Debug, PartialEq)]
 pub struct VMTable {
     pub(crate) table: JsTable,
@@ -138,11 +140,14 @@ impl VMTable {
     pub(crate) fn new(table: JsTable, ty: TableType) -> Self {
         Self { table, ty }
     }
+
+    /// Get the table size at runtime
     pub fn get_runtime_size(&self) -> u32 {
         self.table.length()
     }
 }
 
+/// The VM Function type
 #[derive(Clone)]
 pub struct VMFunction {
     pub(crate) function: JsFunction,
diff --git a/lib/api/src/store.rs b/lib/api/src/store.rs
index 7111c5022..5e59b5113 100644
--- a/lib/api/src/store.rs
+++ b/lib/api/src/store.rs
@@ -13,7 +13,7 @@ use wasmer_vm::init_traps;
 pub use wasmer_vm::TrapHandlerFn;
 
 #[cfg(feature = "sys")]
-use crate::sys::WasmerCompilerEngine;
+use crate::sys::NativeEngineExt;
 #[cfg(feature = "sys")]
 pub use wasmer_vm::{StoreHandle, StoreObjects};
 
diff --git a/lib/api/src/sys/engine.rs b/lib/api/src/sys/engine.rs
index 1eac9ab90..38700d1fe 100644
--- a/lib/api/src/sys/engine.rs
+++ b/lib/api/src/sys/engine.rs
@@ -65,7 +65,7 @@ impl From<EngineBuilder> for crate::engine::Engine {
 
 /// The custom trait to access to all the `sys` function in the common
 /// engine.
-pub trait WasmerCompilerEngine {
+pub trait NativeEngineExt {
     /// Create a new `Engine` with the given config
     #[cfg(feature = "compiler")]
     fn new(compiler_config: Box<dyn CompilerConfig>, target: Target, features: Features) -> Self;
@@ -95,7 +95,7 @@ pub trait WasmerCompilerEngine {
     fn tunables(&self) -> &dyn Tunables;
 }
 
-impl WasmerCompilerEngine for crate::engine::Engine {
+impl NativeEngineExt for crate::engine::Engine {
     fn new(compiler_config: Box<dyn CompilerConfig>, target: Target, features: Features) -> Self {
         crate::engine::Engine(Engine::new(compiler_config, target, features))
     }
diff --git a/lib/api/src/sys/externals/memory.rs b/lib/api/src/sys/externals/memory.rs
index 63c1711dd..e61c3aeeb 100644
--- a/lib/api/src/sys/externals/memory.rs
+++ b/lib/api/src/sys/externals/memory.rs
@@ -1,6 +1,6 @@
 use super::memory_view::MemoryView;
 use crate::store::{AsStoreMut, AsStoreRef};
-use crate::sys::WasmerCompilerEngine;
+use crate::sys::NativeEngineExt;
 use crate::vm::VMExternMemory;
 use crate::MemoryAccessError;
 use crate::MemoryType;
diff --git a/lib/api/src/sys/externals/table.rs b/lib/api/src/sys/externals/table.rs
index 646dd30e8..7fc7b08cd 100644
--- a/lib/api/src/sys/externals/table.rs
+++ b/lib/api/src/sys/externals/table.rs
@@ -1,5 +1,5 @@
 use crate::store::{AsStoreMut, AsStoreRef};
-use crate::sys::WasmerCompilerEngine;
+use crate::sys::NativeEngineExt;
 use crate::TableType;
 use crate::Value;
 use crate::{vm::VMExternTable, ExternRef, Function, RuntimeError};
diff --git a/lib/api/src/sys/mod.rs b/lib/api/src/sys/mod.rs
index 0fc537a54..254e13b03 100644
--- a/lib/api/src/sys/mod.rs
+++ b/lib/api/src/sys/mod.rs
@@ -6,7 +6,7 @@ pub(crate) mod module;
 mod tunables;
 pub(crate) mod typed_function;
 
-pub use crate::sys::engine::WasmerCompilerEngine;
+pub use crate::sys::engine::NativeEngineExt;
 pub use crate::sys::tunables::BaseTunables;
 pub use target_lexicon::{Architecture, CallingConvention, OperatingSystem, Triple, HOST};
 #[cfg(feature = "compiler")]
diff --git a/lib/api/src/sys/module.rs b/lib/api/src/sys/module.rs
index 4d450b141..1eca3fa19 100644
--- a/lib/api/src/sys/module.rs
+++ b/lib/api/src/sys/module.rs
@@ -1,5 +1,5 @@
 use crate::engine::AsEngineRef;
-use crate::sys::engine::WasmerCompilerEngine;
+use crate::sys::engine::NativeEngineExt;
 use bytes::Bytes;
 use std::path::Path;
 use std::sync::Arc;
diff --git a/lib/api/src/sys/tunables.rs b/lib/api/src/sys/tunables.rs
index 379cedfce..80111464f 100644
--- a/lib/api/src/sys/tunables.rs
+++ b/lib/api/src/sys/tunables.rs
@@ -6,7 +6,7 @@ pub use wasmer_compiler::BaseTunables;
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::sys::WasmerCompilerEngine;
+    use crate::sys::NativeEngineExt;
     use crate::TableType;
     use std::cell::UnsafeCell;
     use std::ptr::NonNull;
diff --git a/lib/api/src/vm.rs b/lib/api/src/vm.rs
index e2dabb260..8fc058d64 100644
--- a/lib/api/src/vm.rs
+++ b/lib/api/src/vm.rs
@@ -3,8 +3,7 @@
 #[cfg(feature = "js")]
 pub(crate) use crate::js::vm::{
     VMExtern, VMExternFunction, VMExternGlobal, VMExternMemory, VMExternRef, VMExternTable,
-    VMFuncRef, VMFunction, VMFunctionBody, VMFunctionEnvironment, VMGlobal, VMInstance, VMMemory,
-    VMSharedMemory, VMTable, VMTrampoline,
+    VMFuncRef, VMFunctionBody, VMFunctionEnvironment, VMInstance, VMTrampoline,
 };
 
 #[cfg(feature = "sys")]
@@ -13,17 +12,18 @@ pub(crate) use crate::sys::vm::{
     VMFuncRef, VMFunctionBody, VMFunctionEnvironment, VMInstance, VMTrampoline,
 };
 
+#[cfg(feature = "js")]
+pub use crate::js::vm::{VMFunction, VMGlobal, VMMemory, VMSharedMemory, VMTable};
+
+#[cfg(feature = "sys")]
+pub use wasmer_vm::{VMFunction, VMGlobal, VMMemory, VMSharedMemory, VMTable};
+
 // Needed for tunables customization (those are public types now)
 #[cfg(feature = "sys")]
 pub use wasmer_vm::{
     // An extra one for VMMemory implementors
     LinearMemory,
-    VMFunction,
-    VMGlobal,
-    VMMemory,
     VMMemoryDefinition,
-    VMSharedMemory,
-    VMTable,
     VMTableDefinition,
 };
 
diff --git a/lib/wasi/src/bin_factory/exec.rs b/lib/wasi/src/bin_factory/exec.rs
index eec9ca32b..b53df25c0 100644
--- a/lib/wasi/src/bin_factory/exec.rs
+++ b/lib/wasi/src/bin_factory/exec.rs
@@ -12,7 +12,7 @@ use futures::Future;
 use tokio::sync::mpsc;
 use tracing::*;
 #[cfg(feature = "sys")]
-use wasmer::WasmerCompilerEngine;
+use wasmer::NativeEngineExt;
 use wasmer::{FunctionEnvMut, Instance, Memory, Module, Store};
 use wasmer_wasi_types::wasi::{Errno, ExitCode};
 
diff --git a/lib/wasi/src/runtime/task_manager/mod.rs b/lib/wasi/src/runtime/task_manager/mod.rs
index 70fd95664..d78e412f8 100644
--- a/lib/wasi/src/runtime/task_manager/mod.rs
+++ b/lib/wasi/src/runtime/task_manager/mod.rs
@@ -6,13 +6,8 @@ use std::{pin::Pin, time::Duration};
 
 use ::tokio::runtime::Handle;
 use futures::Future;
-use wasmer::MemoryType;
-
-#[cfg(feature = "js")]
-use wasmer::VMMemory;
-
-#[cfg(not(target_family = "wasm"))]
 use wasmer::vm::VMMemory;
+use wasmer::MemoryType;
 
 #[cfg(feature = "sys")]
 use wasmer_types::MemoryStyle;
diff --git a/lib/wasi/src/state/env.rs b/lib/wasi/src/state/env.rs
index 76690a517..246b07188 100644
--- a/lib/wasi/src/state/env.rs
+++ b/lib/wasi/src/state/env.rs
@@ -4,7 +4,7 @@ use derivative::Derivative;
 use rand::Rng;
 use tracing::{trace, warn};
 #[cfg(feature = "sys")]
-use wasmer::WasmerCompilerEngine;
+use wasmer::NativeEngineExt;
 use wasmer::{
     AsStoreMut, AsStoreRef, FunctionEnvMut, Global, Instance, Memory, MemoryView, Module,
     TypedFunction,
diff --git a/lib/wasi/src/syscalls/wasix/proc_fork.rs b/lib/wasi/src/syscalls/wasix/proc_fork.rs
index ac4bdf3df..7fdfe7deb 100644
--- a/lib/wasi/src/syscalls/wasix/proc_fork.rs
+++ b/lib/wasi/src/syscalls/wasix/proc_fork.rs
@@ -1,10 +1,7 @@
 use super::*;
 use crate::syscalls::*;
 
-#[cfg(feature = "sys")]
 use wasmer::vm::VMMemory;
-#[cfg(feature = "js")]
-use wasmer::VMMemory;
 
 /// ### `proc_fork()`
 /// Forks the current process into a new subprocess. If the function
diff --git a/lib/wasi/src/syscalls/wasix/thread_spawn.rs b/lib/wasi/src/syscalls/wasix/thread_spawn.rs
index db8661649..d0df6631e 100644
--- a/lib/wasi/src/syscalls/wasix/thread_spawn.rs
+++ b/lib/wasi/src/syscalls/wasix/thread_spawn.rs
@@ -1,10 +1,7 @@
 use super::*;
 use crate::syscalls::*;
 
-#[cfg(feature = "sys")]
 use wasmer::vm::VMMemory;
-#[cfg(feature = "js")]
-use wasmer::VMMemory;
 
 /// ### `thread_spawn()`
 /// Creates a new thread by spawning that shares the same