diff --git a/discovery-utils/build.rs b/discovery-utils/build.rs
index 6d5f169a3..6ec0bc4e8 100644
--- a/discovery-utils/build.rs
+++ b/discovery-utils/build.rs
@@ -1,6 +1,7 @@
 fn main() {
     tonic_build::configure()
         .out_dir("./src/discovery")
+        .protoc_arg("--experimental_allow_proto3_optional")
         .compile(&["proto/discovery.proto"], &["proto"])
         .expect("failed to compile protos");
 }