diff --git a/objc2-proc-macros/src/derive.rs b/objc2-proc-macros/src/derive.rs
new file mode 100644
index 000000000..4ee6aab4e
--- /dev/null
+++ b/objc2-proc-macros/src/derive.rs
@@ -0,0 +1,28 @@
+use proc_macro::TokenStream;
+use quote::quote;
+use syn::DeriveInput;
+
+pub(crate) fn impl_encode(ast: &DeriveInput) -> TokenStream {
+    let name = &ast.ident;
+    let gen = quote! {
+        unsafe impl ::objc2_encode::Encode for #name {
+            const ENCODING: ::objc2_encode::Encoding<'static> = ::objc2_encode::Encoding::Struct(
+                stringify!(#name),
+                &[CGFloat::ENCODING, CGFloat::ENCODING],
+            );
+        }
+    };
+    gen.into()
+}
+
+pub(crate) fn impl_ref_encode(ast: &DeriveInput) -> TokenStream {
+    let name = &ast.ident;
+    let gen = quote! {
+        unsafe impl ::objc2_encode::RefEncode for #name {
+            const ENCODING_REF: ::objc2_encode::Encoding<'static> = ::objc2_encode::Encoding::Pointer(
+                &<Self as ::objc2_encode::Encode>::ENCODING
+            );
+        }
+    };
+    gen.into()
+}
diff --git a/objc2-proc-macros/src/lib.rs b/objc2-proc-macros/src/lib.rs
index 604e6c7a0..9572d3d60 100644
--- a/objc2-proc-macros/src/lib.rs
+++ b/objc2-proc-macros/src/lib.rs
@@ -19,16 +19,18 @@ extern "C" {}
 
 use proc_macro::TokenStream;
 
+mod derive;
+
 /// TODO
 #[proc_macro_derive(Encode)]
 pub fn encode_derive(input: TokenStream) -> TokenStream {
-    dbg!(input);
-    todo!()
+    let ast = syn::parse(input).unwrap();
+    derive::impl_encode(&ast)
 }
 
 /// TODO
 #[proc_macro_derive(RefEncode)]
 pub fn ref_encode_derive(input: TokenStream) -> TokenStream {
-    dbg!(input);
-    todo!()
+    let ast = syn::parse(input).unwrap();
+    derive::impl_ref_encode(&ast)
 }