diff --git a/packages/connect-conformance/package.json b/packages/connect-conformance/package.json
index 3f5169ed6..250d698f8 100644
--- a/packages/connect-conformance/package.json
+++ b/packages/connect-conformance/package.json
@@ -37,6 +37,7 @@
     "@bufbuild/buf": "^1.36.0",
     "@types/node-forge": "^1.3.9",
     "@types/tar-stream": "^3.1.3",
-    "@types/debug": "^4.1.12"
+    "@types/debug": "^4.1.12",
+    "@connectrpc/protoc-gen-connect-es": "1.4.0"
   }
 }