diff --git a/Cargo.toml b/Cargo.toml
index 9e8a06ac4..b2b9989eb 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -81,6 +81,7 @@ url = "2.2"
 bytes = "1.0"
 serde = "1.0"
 serde_urlencoded = "0.7.1"
+tower-service = "0.3"
 
 # Optional deps...