diff --git a/macro/Cargo.toml b/macro/Cargo.toml
index 48fb6d48..27f0252a 100644
--- a/macro/Cargo.toml
+++ b/macro/Cargo.toml
@@ -14,11 +14,19 @@ categories = ["development-tools::ffi"]
 [lib]
 proc-macro = true
 
+[features]
+experimental = ["clang-ast", "serde", "serde_json"]
+
 [dependencies]
 proc-macro2 = "1.0"
 quote = "1.0.4"
 syn = { version = "1.0.68", features = ["full"] }
 
+# optional dependencies
+clang-ast = { version = "0.1", optional = true }
+serde = { version = "1.0", optional = true, features = ["derive"] }
+serde_json = { version = "1.0", optional = true }
+
 [dev-dependencies]
 cxx = { version = "1.0", path = ".." }