diff --git a/lib/deprecated/runtime-core/doc/new-api/instance.rs b/lib/deprecated/runtime-core/doc/new-api/instance.rs
new file mode 100644
index 000000000..770429a8d
--- /dev/null
+++ b/lib/deprecated/runtime-core/doc/new-api/instance.rs
@@ -0,0 +1,18 @@
+struct Instance {
+    module: Arc<ModuleInner>,
+    exports: Exports,
+}
+
+impl Instance {
+    fn load<T: Loader>(&self, loader: T) -> Result<T::Instnace, T::Error>;
+    fn fun<Args, Rets>(&self, name: &str) -> ResolveResult<Args, Rets, Wasm>;
+    fn resolve_func(&self, name: &str) -> ResolveError<usize>;
+    fn dyn_func(&self, name: &str) -> ResolveResult<DynFunc>;
+    fn call(&self, name: &str, params: &[Value]) -> CallResult<Vec<Value>>;
+    fn context(&self) -> &Ctx;
+    fn context_mut(&mut self) -> &mut Ctx;
+    fn exports(&self) -> ExportsIter;
+    fn module(&self) -> Module;
+    fn get_internal(&self, fields: &InternalField) -> u64;
+    fn set_internal(&self, fields: &InternalField, value: u64);
+}
diff --git a/lib/deprecated/runtime-core/doc/new-api/module.rs b/lib/deprecated/runtime-core/doc/new-api/module.rs
new file mode 100644
index 000000000..2963786ec
--- /dev/null
+++ b/lib/deprecated/runtime-core/doc/new-api/module.rs
@@ -0,0 +1,10 @@
+struct Module {}
+
+impl Module {
+    fn instantiate(&self, import_object: &ImportObject) -> Result<Instance>;
+    fn cache(&self) -> Result<Artifact, CacheError>;
+    fn info(&self) -> &ModuleInfo;
+    fn imports(&self) -> Vec<ImportDescriptor>;
+    fn exports(&self) -> Vec<ExportDescriptor>;
+    fn custom_sections(&self, key: impl AsRef<str>) -> Option<&[Vec<u8>]>
+}
diff --git a/lib/deprecated/runtime-core/doc/old-api/instance.rs b/lib/deprecated/runtime-core/doc/old-api/instance.rs
new file mode 100644
index 000000000..09c743e94
--- /dev/null
+++ b/lib/deprecated/runtime-core/doc/old-api/instance.rs
@@ -0,0 +1,12 @@
+struct Instance {
+    exports: Exports,
+}
+
+impl Instance {
+    fn load<T>(&self, _loader: T) -> Result<Self, ()>;
+    fn resolve_func(&self, name: &str) -> Result<usize, ()>;
+    fn call(&self, name: &str, params: &[Value]) -> Result<Vec<Value>, Box<dyn Error>>;
+    fn context(&self) -> Ref<Ctx>;
+    fn context_mut(&mut self) -> RefMut<Ctx>;
+    fn module(&self) -> Module;
+}
diff --git a/lib/deprecated/runtime-core/doc/old-api/module.rs b/lib/deprecated/runtime-core/doc/old-api/module.rs
new file mode 100644
index 000000000..e49c528cb
--- /dev/null
+++ b/lib/deprecated/runtime-core/doc/old-api/module.rs
@@ -0,0 +1,10 @@
+struct Module {}
+
+impl Module {
+    fn instantiate(&self, import_object: &ImportObject) -> Result<Instance, InstantiationError>;
+    fn cache(&self) -> Result<Artifact, Infallible>;
+    fn info(&self) -> &ModuleInfo;
+    fn imports(&self) -> Vec<ImportDescriptor>;
+    fn exports(&self) -> Vec<ExportDescriptor>;
+    fn custom_sections(&self, name: impl Asref<str>) -> Option<Vec<Vec<u8>>>;
+}